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Assessment of Mercury Releases from the Russian Federation 3 Intentional use of Mercury
3.1 Chlor-alkali ProductionAbout half of the chlorine produced in the Russian Federation is produced by using the mercury electrode method. The other part is produced by the diaphragm method. At present, there are four chlor-alkali (chlorine and caustic soda) production facilities which use mercury in the Russian Federation [2]:
The following outdated production facilities were closed in 1980-s –1990-s:
Besides, in 1990-s small chlor-alkali production facilities operated in paper and pulp factories of Svetlogorsk (Leningrad oblast), Novodvinsk (Arkhangelsk oblast), Koryazhma (Arkhangelsk oblast) and Komsomolsk-on-Amur (Amur oblast) were closed. Mercury in local waste dumps and the environment (soil in particular) around these closed down factories is further described in section 3.1.5. Location of facilities for production of chlorine, caustic soda and vinyl chloride in the Russian Federation is shown on figure 3.1. Figure 3.1 Location of facilities for production of chlorine, caustic soda and vinyl chloride in the Russian Federation (indicated by C) Click here to see the figure.3.1.1 Description of Production Process and Mercury UsageThe schematic process layout indicating the basic mercury flows and release sources is presented in figure 3.2 below. Caustic soda (NaOH), chlorine and hydrogen are produced by electrolysis of a saturated water solution of sodium chloride (brine) [3] in a horizontal bath with a mercury cathode. The bath includes an electrolyser, an amalgam decomposer and a mercury pump. Figure 3.2 Process scheme of chlor-alkali production using mercury electrodes
In the electrolyser, the electrolysis of the sodium chloride solution with formation of chlorine gas and a sodium amalgam (a sodium mercury alloy) takes place. The formed chlorine gas goes from the electrolyser to cooling and drying (dehydration). Small amounts of mercury follow the chlorine gas. The sodium amalgam is an intermediate product in the process and serves for the transfer of the generated NaOH from the electrolyser to the decomposer ensuring formation of a concentrated NaOH solution with minimal impurity of chloride. The amalgam flows from the electrolyser through a mercury seal to the output pool and then to the decomposer. The decomposer is a short-circuited electrical cell in which the sodium amalgam acts as the anode and graphite as the cathode in a sodium hydroxide solution. Softened water is added to the decomposer where it reacts with the sodium amalgam to produce elemental mercury, sodium hydroxide, and by-product hydrogen gas. Mercury is partially released from the decomposer within hydrogen and NaOH, which consequently require mercury removal. The input and output pools are supplied with softened water for the amalgam washing and cooling, as well as mercury evaporation decrease. Flue gases exhausted from the pools containing chlorine and Hg vapours are directed to the treatment facilities. Elemental mercury is recirculated back to the electrolyzer along a pipeline through a cooler, where is it cooled with water. The continuous circulation of mercury in the closed cycle is provided by a mercury pump. When the mercury content of the electrolyser is decreased below established norms the necessary volume of mercury is added to the bath. The hydrogen recovered from the amalgam decomposition is cooled with water in heat exchangers installed on the decomposer's covers. Most part of Hg vapours is condensed and returned to decomposer. After cooling the hydrogen goes to a treatment and compression unit. A part of the recovered hydrogen is used for synthesis of hydrochloric acid or other products; the rest is released to the atmosphere after mercury removal. The caustic soda solution with 45-50% mass share flows from the decomposer's top to collection tank where it is cooled and filtered and then supplied to the consumers. Water after washing and degassing of the electrolysis room's floors is collected to the container from where it is pumped to the mercury removal unit. The quality of the brine fed to the electrolysis should be very high, first of all regarding iron content (not higher than 0.1 mg/dm3) and heavy metals (sum of vanadium, molybdenum and chrome - not more than 0.01 mg/dm3). These requirements are concerned with the fact that by the recovering of the amalgam to elemental mercury mercury, the metals promote formation of so called "amalgam butter" – a viscous mass with ferromagnetic properties (in case of iron) and a foamy mass (in case of vanadium, molybdenum, chrome). Generation of amalgam butter seriously destroys the electrolysers' performance necessitating frequent cleansing connected with unavoidable losses of mercury at the electrolysis stops. The electrolysis solution can be prepared by various methods and the selection of method has some influence on the formation of mercury-containing sludge: (1) Evaporation of underground brine after its preliminary purification. Clean evaporated salt is then used for additional saturation of spent after-electrolysis brine which is returned to the electrolysis after fine filtration (anolyte cycle). Simplicity of brine purification in anolyte cycle due to the use of clean evaporated salt is the main advantage of this method. It allows mercury dissolved in the brine coming out of the electrolysers to return back to electrolysers rather than being removed from the cycle. Additional operation stage - brine evaporation - is the main disadvantage of this method. (2) Additional saturation of spent brine with salt recovered from evaporation of alkaline solution at a diaphragm electrolysis plant. Application of this method is possible at those enterprises where both mercury cell method and diaphragm method are used. It may be combined with the above-mentioned method. The advantages are: (a) minimum amount of mercury is lost with brine sludge; (b) within the production cycle salt evaporation costs are significantly decreased if not eliminated at all. (3) The dilution of halite deposit (or native sodium chloride as it is called in Russia), which is brought up to the site, takes place in solution tanks where calcium, magnesium, iron and heavy metals are removal and the purified brine, after deep filtration, is pumped directly to electrolysers and from electrolysers it is fed back to the solution tanks for additional saturation and further removal of impurities. The advantage of this method is that there is no need for brine evaporation, more over this method provides higher quality of purification and allows to remove more heavy metals, thus improving the efficiency of electrolysis. Unavoidable loss of dissolved mercury, which is taken away from the electrolysis after its sedimentation as insoluble sulphide during the process of heavy metals removal, is a disadvantage because industrial utilisation of such insoluble and Hg lean sulphide is very problematic and thus it is not practised. Due to lack of current assets, high cost of mercury and tough requirements on issue of permits for its purchase, almost all enterprises had very limited stocks of mercury or had no stocks at all during the latest 5 years. While it should be noted that incomplete charging of electrolysers with Hg is very undesirable due to a negative impact on electrolysis indicators resulting in Hg losses increase, i.e. this deficit aggravation. The caustic soda production by mercury method for the latest 5 years is presented in Table 3.1. The main consumers of chlorine produced in sodium chloride electrolysis are plants for production of polyvinyl chloride, epichlorohydrins, trichloroethylene, dichloroethane, and other production plants. After fulfilment of RF Government of the engagements related to the Montreal agreements and closure of ozone depleting coolants and carbon tetrachloride productions, chlorine consumption has considerably decreased resulting in lowering of electrolysis loads and caustic soda production, both by the mercury and by the diaphragm method. Table 3.1 Caustic soda production using mercury in RF, 1998-2002
3.1.2 Pathways of Mercury Loss from Production ProcessesAs follows from the above description of the production process, the main pathways of mercury loss are caustic soda, hydrogen, wastewater, off-gases, chlorine, sludge, ventilation release, and mechanical losses. The magnitude of losses is determined by the applied technological process, how the technological conditions are observed, as well as by the general production culture, and availability and efficacy of operation of mercury treatment units. Magnitudes of losses according to the first five pathways are, as a rule, small and easy to adjust, provided the relevant mercury removal processes are used. Mercury lost with caustic soda, chlorine and hydrogen is distributed, in negligible amounts, among users of such products and is ultimately released to the environment or waste by the use or disposal of the products. Mercury lost with off-gases, a part of hydrogen, unused in production, and with ventilation release is emitted to the atmosphere, while mercury discharged with non-recycled wastewater is discharged to the aquatic environment. Losses of mercury with brine slurry are defined by the brine treatment methods used at production facilities. When salt is brought from outside without evaporation of the primary brine, such losses are big, and when clean evaporated salt is used such losses are small. Brine slurry with a low concentration of mercury is not treated; rather it is compacted and accumulated at specially equipped and controlled landfills at the production sites. Magnitude of loss of mercury with other types of sludge, removed from electrolysers during treatment, or formed during backwash of filters, or after sedimentation of wastewater, or removed from spent graphite in decomposers, activated carbon, ion-exchange resins, etc., can be minimized through thermal regeneration of mercury from them. Losses of mercury as a result of release resultant from intensive ventilation of the electrolysis room cannot be, practically, reduced by any other means, but only through a high organization of production, including sealing of bathtubs and, above all, amalgam decomposers, maximum decrease of stops and cleanups of bathtubs, accidental spilling and leakage of mercury, and through organization of proper collection of spilled mercury. Mercury vapours released through ventilation by aeration lanterns in the electrolysis room are condensed and precipitated on the constructions and into the soil within the area adjacent to the production facility. Under the impact of atmospheric precipitation and natural processes of evaporation and condensation such mercury may get into water bodies and hence beyond the primary discharge area. Mercury can be lost from the electrolysers and decomposers with leaks – occasional or caused by flanges unsealing, as slag and during cleansing with anolyte. Number of these losses significantly depends on electrolysers operating procedures, their constructive features and non-stop functioning periods' duration. Losses of mercury in production, as enumerated above, when it gets into air, water bodies or special storage facilities, are easy to control and, as the global experience shows, should be indicated in the reports of the enterprises. However, in such case they do not take into account mechanical losses resultant from incomplete catch and return of mercury spill during maintenance and repairs of electrolysers. Such losses may constitute a significant part of the total losses of mercury in chlorine-alkali production. In the technical reports of enterprises of the former USSR and of the Russian Federation such losses are indicated as part of general use of mercury, which gives an idea that such losses are extremely high as compared to similar indicators of other countries. Mechanical losses may be calculated only as a difference between the quantity of mercury brought from outside so as to supplement for its losses through other causes during a long period of time (a three-month period or a year). The losses from enterprises in the Russian Federation are in the summary, section 3.1.6, compared with losses reported from other countries (OSPAR 2002). Reduction of mechanical losses can be reached through a maximum decrease of stops of electrolysers for cleanup and repairs, strict observing of maintenance standards and technological discipline, improved quality of repair, organisation of permanent collection and return to electrolysers of spilt mercury treated additionally to the required standard, organisation of sealed floors in electrolysis room, arrangement of trays and pits for collection of wastewater and spilt mercury and through vacuum collection of mercury. At the same time it should be noted that the issue of environmental role played by mercury lost mechanically is ambiguous. Mercury can get into soil through unsealed floors of production buildings (above all, from the electrolysis building) and then accumulated in underground layers. The depth of its penetration and ways of its further migration, including possible getting into water bodies, is defined by geological; features of the area. In view of this, it is necessary to keep in mind that directly under the buildings wherein chlor-alkali production facilities have been in place for several decades, as well as within the area adjacent to such buildings metallic mercury may get accumulated in amounts up to several hundred tonnes. Therefore, issues of containment of mercury migration as well as issues of its possible return are very important. Such issues can be resolved only with participation of geological services. 3.1.3 Methods of Mercury Removal from Products, Discharges, Waste and Off-gasesTo prevent emission of mercury to atmosphere and it's getting into water bodies, enterprises producing caustic soda and chlorine using mercury methods apply methods for cleanup of gaseous, liquid and solid waste, thereby reducing the content of mercury below the set standards. Thus, to prevent emission of harmful gases to air in the electrolysis room, it is provided to clean off-gases from mercury – such gases are sucked from the outlet pockets of electrolysers by fans. Further, such gases are cooled to a temperature not higher than 15 °C so as to condense part of mercury and water vapours. Cooled off-gases pass through a fog separator to remove mercury drops, and then through filters with a double layer of activated carbon so as to remove mercury vapours. After the filter the off-gases with a mass concentration of mercury not more than 0.01 mg/m3 are released to atmosphere. The spent packing is sent for regeneration. Off-gases containing chlorine and mercury, sucked off the inlet boxes, are sent to be cleaned by an alkaline solution of sodium hypochlorite. Condensate of mercury and water vapours from the cooler and the filter is collected to the receiver and pumped to the plant where it is cleaned from mercury. After pre-treatment from the bulk mercury removed from the decomposer in the coolers, installed directly at the decomposers, hydrogen is fed for final cleanup from mercury. Mercury removed with hydrogen is partially condensed in hydraulic valves installed on the hydrogen collector, wherefrom it is collected and returned to the electrolysers. Then, hydrogen is cooled to temperature not more than 15 °C and fed to the filter wherein the bulk drops of mercury are retained. Then, hydrogen is fed to the suction side of the hydrogen collector. After the compressor, hydrogen is cooled to temperature not more than 40 °C and fed for the final stage of mercury vapour clean to the filters packed with activated carbon. The spent packing of the filters is sent for thermal regeneration. Cleaned hydrogen with the mass concentration of mercury not more than 0.01 mg/m3 is sent to users or released to atmosphere. When caustic soda and chlorine are produced using a mercury method, caustic soda solution is filtered from fine-dispersion metallic mercury and graphite dust entrained from the decomposers. Caustic soda after the decomposers is cooled to temperature 55-75 °C and then is fed for filtration. Cleaned solution with NaOH content not less than 46% and the mass share of mercury not more than 0.00007% is fed to users or to storage tanks. Mercury slurry and amalgam oil from the electrolysis room are fed in drums to the regeneration bay for treatment, including a preliminary settlement or separation of the bulk mercury portion followed by thermal regeneration. Liquid mercury separated from slurry is fed to metal cylinders, while slurry is sent to the regeneration bay for mercury regeneration in electrically heated ovens. All solid waste containing mercury, spent packing of the filters for hydrogen and alkaline cleanup, as well as sorbents from wastewater treatment plants are sent there; exception is brine cleanup slurry with small volumes and a low concentration of mercury. For de-mercuration of spent bulky equipment before such equipment is processed as scrap, special tunnel ovens are used. Off-gases are sucked from the tank wherein the slurry is treated by a fan and sent to the sanitation adsorbent filter for cleanup, and then they are released to atmosphere, provided the mercury concentration is not higher than 0.01 mg/ m3. Slurry is loaded to the oven, which is then tightly closed. Regeneration is done at a temperature of 500 C, with rarefaction of 10-20 mm of water column built by the fan. A mixture of gases with mercury vapours is passed from the oven by the tubular condenser cooled by circulating water. The condensed metallic mercury is fed to the collector wherefrom it is fed to electrolysers as required. To prevent oxidation of mercury, a low flow of nitrogen is fed to the oven. Wastewater is cleaned from mercury by sorption method in ion-exchange resins, with pre-oxidation of metallic and monovalent mercury, as well as by transferring mercury compounds to water-insoluble HgCl2_ through chlorination of wastewater by gaseous chlorine or to an insoluble HgS through treatment by sodium hydrosulphide. After the mercury has been transferred to insoluble state, water is fed for filtration through mechanical filters. When chlorination treatment is used, wastewater is fed, after filtration, to the absorber filled with activated carbon – for de-chlorination. This is done to prevent active chlorine getting into treated wastewater. Wastewater cleaned from the bulk mercury is fed by pumps to the absorbers filled with ion-exchange resin. The number of absorbers used is from 2 to 6 absorbers. Resins of different brands can be fed into them sequentially. Treated water, with the mercury concentration not more than 0.005 mg/l, is fed to the tank, wherefrom it is pumped to clarification tanks. After cleanup, wastewater neutralised by alkaline can be sent to tanks for their reuse in production. When cleaned water does not meet the standards, it is fed for a new cleanup. Spent ion-exchange resin with the mercury concentration of 40% is fed, from the first absorber, as well as up to 10% from other absorbers, to the mercury regeneration plant or to the mercury processing enterprise. 3.1.4 Production of Chlor-alkali and Mercury Loss at Operating Enterprises3.1.4.1 Kirovo-Chepetsk Chemical Enterprise OJSC The electrolysis room is equipped with electrolysers P-20M and vertical decomposers. Totally, 92 electrolysers are installed, rated 200 kA, and the output of caustic soda at 207,000 tonnes. In 1997, there were 47 electrolysers in operation, rated 84 kA. In 2002, there were 63 electrolysers, rated 79 kA. Preparation and cleanup of brine for electrolysis is made by additional saturation of anolyte cycle with untreated solid salt, followed by its complete cleanup from admixtures, including sulphide. Raw materials used for production of chlorine and caustic soda include salt transported from the Baskunchak fields. Final saturation of brine, circulating in production, is done directly in salt solutions, while cleanup with soda and alkaline and sulphide method is done in Dorr settling tanks followed by filtration. The process applied provides for a high degree of brine clarification from admixtures that are harmful for the process, but it also includes a loss of all mercury dissolved in the anolyte during electrolysis process and fed for its dechlorination and final saturation. The design and the quality of maintenance of the electrolysers ensures, in addition to a high cleanup of the feeding brine, minimum mechanical losses of mercury with wastewater and entrainment by ventilation air. Regeneration of mercury form slurry in the electrolysis bay, after a preliminary separation from them of the bulk mercury in a reactor with a stirrer, as well as from the spent reagents from the plants for treatment of hydrogen, caustic soda, wastewater, etc., is done by the method of thermal recovery in a blast oven, following which the recovered mercury is returned for electrolysis. There are no any noticeable losses of mercury during this operation. Production waste containing metallic mercury (spent bottoms of the electrolysers, hydrogen and mercury coolers, amalgam decomposers, buffer tanks and other contaminated equipment) is thermally treated before being used as scrap or transferred to the site for disposal of waste classified as 3 or 4 class hazard waste. Metallic mercury is used in production, after the vapours are condensed. Before releasing to atmosphere, contaminated air is cleaned by adsorbent HPR-2 (in Russian – ÕÏÐ-2) Losses of mercury during production process include losses with brine cleaning slurry, wastewater discharged to the wastewater removal system, with ventilation discharge, off-gases and hydrogen emitted to atmosphere, with air released from the waste thermal treatment plant, with waste after thermal regeneration of mercury slurry, with products (chlorine, caustic soda and the part of hydrogen used to produce hydrochloric acid), and with groundwater, including loss resultant from discharge of mercury through the enterprise rainwater discharge system, filtration of non-cleaned wastewater through the floors in the electrolysis room and drainage from the slurry accumulators. Below is given assessment of such losses for 1997 and 2002. Losses of mercury with salt-dissolution slurry Before 1997, mercury-containing slurry from brine cleanup at the Dorr settling basins and after regeneration of sand filters had been filtered at drum vacuum filters and then discharged to a slurry accumulator, i.e. a banked controlled area of 4.5 hectares, whose bottom and banks were made from moisture impermeable clay. Also, spent sulphuric acid from the chlorine drying stage and the wastewater after sulphide settling of mercury were discharged to the same area. Excessive clarified water from the slurry accumulator with mercury concentration up to 0.05 mg/l in the amount of 10-15 m3/h was discharged to the wastewater removal system of the enterprise. Salt-dissolution slurry containing insoluble mercury sulphide was stored in the controlled area designed for storage of waste rated as waste belonging to 3 or 4 hazard class. When sections of the site were filled with slurry, such areas were covered by a layer of fluorine gypsum. In 1998, a unit for deep wastewater treatment was put into operation at the plant. This increased the degree of wastewater treatment and reduced the volume of treated wastewater; brine cleaning slurry from the Dorr settling basins was fed to the salt dissolvers followed by its storage, together with the salt dissolution slurry, in the area designed for disposal of waste classified as 3-4 class hazard waste. This made it possible to stop using the slurry accumulator and completely terminate discharge of wastewater from it. Since 2002, the plant for decomposition of brine-cleaning carbonate slurry by means of hydrochloric acid was put into operation, which allows returning the generated chlorine calcium to the salt dissolution stage. This made it possible to reduce volumes of stored slurry. Losses of mercury with slurry generated during brine dissolution and cleaning were:
Losses of mercury with wastewater Before 1998, wastewater had been treated by the method of mercury precipitation as an insoluble sulphide, followed by its settling in the slurry accumulator and discharge of the clarified water to the wastewater discharge system of the enterprise. In 1998, the deep treatment of wastewater by precipitation of mercury as sulphide was started, including also filtration through KMP-25 filter, storage of sulphide slurry in the area for disposal of waste classified as 3-4 class hazard waste, and followed by a final cleaning of filtered water by an ion-exchange method. Filtration slurry is stored in the site designed for disposal of waste classified as 3-4 class hazard waste. The concentration of mercury in the discharged wastewater makes 0.0008-0.001 mg/dm³, while the norm is 0.001 mg/dm³. Losses of mercury with wastewater were:
Losses of mercury with ventilation discharge The system of ventilation in the electrolysis room is plenum, with outlet through aeration lanterns. The lantern height is 12 mother flow rate of pumped in air is 800-1000 thousand m3/h. Concentration of mercury in discharge is 0.012-0.017 mg/m3. Discharge of mercury through the aeration lanterns of the electrolysis room made:
Losses of mercury with ventilation discharge from the wastewater pumping and cleanup bay made:
The mercury discharge does not exceed the set standard MAD. Losses of mercury with hydrogen Out of the total amount of generated hydrogen, 75% is discharged to atmosphere through a stack 15 m high. Before 1998, two-stage hydrogen cleaning from mercury had been organized through reflux with chloranolyte and alkaline brine. In 1998, deep cleanup method by adsorption in activated carbon was started, which allowed increasing hydrogen cleaning degree by an order of magnitude. Losses of mercury discharged with hydrogen made:
The mercury discharge does not exceed the set standard MAD. In 1997, users inside the enterprise received 2.83 kg of mercury with untreated hydrogen. Losses of mercury with off-gases Cleaning of off-gases from mercury and chlorine is made by saturation of the latter by an alkaline solution of sodium hypochlorite. Discharge of mercury with off-gases made:
The mercury discharge does not exceed the set standard MAD. The spent saturating solution is fed to the anolyte cycle. Losses of mercury with groundwater Losses result from discharge of mercury by the rainwater system of the enterprise with the surface fun-off, filtration of wastewater through the floors in the electrolysis room and drainage from the site for disposal of waste classified as 3-4-class hazard waste They were:
By their origin, they include some part of mercury emitted to atmosphere that is later precipitated on the soil and carried away by rain water, as well as some part of mercury discharged with the residual moisture of mercury-containing slurry and, hence, they must be subtracted from such losses. However, since they also include mercury-containing wastewater a particular part of which lost before its treatment, it is impossible to divide these components in terms of quantity. Losses of mercury with products With synthetic hydrochloric acid (HCl) containing 0.00001% of mercury such losses made:
With caustic soda containing 0.00005% of mercury, such losses made:
Losses of mercury with discharge from the waste chemical treatment plant Losses with discharge of contaminated air after chemical processing (de-mercuration) of waste made:
The mercury discharge did not exceed the set standard MAD. Losses of mercury with slurry after its thermal treatment were:
Mechanical losses of mercury Mechanical losses of mercury include, above all, metallic mercury spilt from the electrolysers, decomposers, pumps and service lines in the process of operation and repair work and mercury lost irrevocably through filtration into the soil through damaged floors. It also includes mercury contained in the part of wastewater filtered through non-tight joints in the floors. As was indicated in section 3.1.2, that such losses can be determined only by the difference between the known amount of mercury filled into the electrolysers from outside during the year and the total fixed losses over the same period of time. In total 15.1 t of mercury was purchased in 2002. In 2002 mechanical losses of mercury calculated in this way made 0.015 kg. The mechanical losses of mercury from the plant is significantly lower than the losses from the other plant due to a high culture of servicing the electrolysers, sealed floors in the electrolysis shop and good organisation of mercury collection. Summary on losses Losses of mercury discharged into the air, water of the settling basins, buried or stored with slurry as well as mechanically lost mercury and lost with merchandise commodities are shown in Table 3.2. Table 3.2 Losses from Kirovo-Chepetsk Chemical Enterprise OJSC
The data shown demonstrate that in 2002 there were a significant reduction of absolute and specific discharge of mercury to the wastewater system and specific losses of mercury with slurry resultant from brine preparation. An insignificant increase of absolute losses of mercury in 2002, as compared to 1997, was related to a growth in the merchandise product output. For Kirovo-Chepetsk plant, relatively small amount of mercury losses from mechanical operations (0.015 kg) resulted from technical upgrading of equipment, high-quality operation of the equipment, controlling equipment repair process, adequate protection of floors, continuous collection and recycling of mercury spills, etc. as described in the present section. Production stocks of mercury There are 92 electrolysers installed in the shop. Of this number, 61 electrolysers are in operations, while the remaining 31 electrolysers are removed from operation. The amount of mercury placed into the electrolyser is 2.71 tethered are 165.3 tonnes of mercury used in the operating electrolysers. The stock of mercury in the electrolysers removed from operation makes 84 tonnes. At present, this stock is already used so as to supplement mercury to the operating electrolysers. The enterprise does not have any other stocks of mercury. Environmental condition By rough estimates, the slurry disposed at the controlled sites ( i.e. in the slurry accumulator and the site for disposal of waste classified as 3-4 class hazard waste) include about 300 to 700 tonnes of mercury, accumulated here over fifty years of the enterprise operation, basically in the form of mercury sulphide. A significant, though hard to quantify amount of mercury sulphide, discharged basically with wastewater during period preceding the transfer to its deep treatment, as well as, possibly, of metallic mercury precipitated from emissions to atmosphere and washed off by atmospheric precipitations, accumulated in benthic sediments of the hydraulic systems within the area adjacent to the area of mercury dissipation, or carried by liquid and gaseous discharge. Also, some quantity of metallic mercury may be present, penetrated into deep soil layers and accumulated in some isolated sections above the Perm clay. According to survey made in 1995 by the State enterprise of environmental and geologic and geographic research, the International Scientific Environmental Centre and the Environmental Fund "Mercury Hazard" (St. Petersburg), Kirovo-Chepetsk Chemical Enterprise ensures maximum possible for this technology degree of mercury safety while environmental situation in the area adjacent the enterprises was estimated as moderately dangerous. It was recognised that a potential source of this hazard was accumulation of mercury and its compounds in benthic slurry, because it can be transferred, by the impact of river biota, into easily soluble and highly toxic organic compounds. The survey did not show any cases of intoxication of people, however, there were cases when the concentration of mercury in liver of wild fish caught within the area of mercury dissipation was above the standard. Concentration of mercury in benthic slurry, as demonstrated by analysis, made from 0.4 to 5.1 mg/kg. However, site for sampling were not indicated. Also, it is possible that mercury may penetrate from the slurry storage sites into groundwater due to absence of safe hydraulic insulation systems; mercury and its compounds may also get into industrial and potable water when water is taken from water wells and shallow wells in individual households located within the indicated dissipation area. It has been forecasted that mercury contamination could further spread downstream during periods of high water or during extraction of sand from the rivers. According to the latest analysis data received by the environmental laboratory of Kirovo-Chepetsk Enterprise, the average concentration of mercury in the surface layer of the soil, within 1 km radius from the enterprise, was 0.2 mg/kg. The average concentration of mercury in water sampled at the control site in the river Prosnitsa (500 m downstream the point of wastewater discharge from the enterprise) amounted to Hg total - 0.0002 mg/dm3, Hg soluble - 0.0001 mg/dm3, which corresponds to the current MAC standard. In the control site of the Vyatka River, downstream of its tributary the Prosnitsa River, the mercury concentration was less than 0.00003 mg/dm3. The average concentration of mercury in benthic sediments at the control site on the Prosnitsa River made ~ 0.2 mg/kg. Options for release reduction 1. The enterprise has a high culture of operation of equipment and a high technological discipline. Over the last 5 years, it has put into operation plants for deep treatment of water and hydrogen and improved the system of discharge and preservation of mercury-containing brine slurry. This has resulted in decreased losses of mercury per unit of production from 0.275 kg/t to 0.250 kg/t. The current norms for maximum allowed discharge of mercury to water and air are observed. 2. Losses of mercury with brine slurry, ventilation discharge from the electrolysis room and groundwater, defined by specific features of the technologies and the conditions of slurry accumulators, make over 99.5% of its total losses. 3. The existing technological scheme does not allow a radical reduction of losses of mercury with brine slurry, without a serious reconstruction of the brine preparation unit. Such reconstruction is extremely difficult because of high capital costs. There are possibilities for further reduction of the total amount of mercury lost in production and a substantial reduction of its losses into water and air. Mercury losses can be reduced through the following measures:
4. At the same time, the main action that could allow cutting down by 99% the amount of mercury lost in production should be the construction of a unit for filtration of anolyte from mercury and reconstruction of the existing plant for thermal treatment of mercury-containing waste. Kaustic OJSC (City of Volgograd) The electrolysis room is equipped with electrolysers R-101 (in Russian P-101) and horizontal amalgam decomposers rated 100 kA. Totally, 104 electrolysers are in operation. Brine for electrolysis is prepared and cleaned by additional saturation of the anolyte cycle by clean evaporated salt followed by filtration in bulk filters. Raw materials used for production of chlorine and caustic soda include evaporated salt from the underground brine and also return salt from alkali evaporation during diaphragm electrolysis. Equipment of saturation units and brine filtration in the anolyte cycle is made from titanium and allows presence of up to 20 mg/l of activated carbon in the cycle. This excludes complete dechlorination of anolyte by treatment of with sulphide, and mercury contained in the brine is preserved in it without loss with brine slurry. Brine from the electrolysers, after vacuum dechlorination, alkalisation and additional saturation, is filtered through bulk filters. After filter regeneration, slurry containing insignificant quantity of mercury chlorides is sent to section N2of the accumulation basin. A more detailed description of the system of controlled sites for waste disposal will be given below, in the chapter "Losses of mercury with wastewater and groundwater". The design of electrolysers should be considered as not completely meeting the modern level of technology development, because, above all, horizontal decomposers and mercury pumps with a cone rotor are used. However, because of regular repair and improvements, quality of their operation remains quite satisfactory while the use of metal-oxide anodes and a high degree of cleanness of the brine makes it possible to have comparatively low mechanical losses and losses with ventilation discharge. In 2001, reconstruction of the floors in the electrolysis building was basically completed, which allowed a substantially simplified process of collection of spilt mercury and prevention of leaks of wastewater and mercury through the floors of the electrolysis room. Recovery of mercury from slurry, collected in the electrolysis building, is made by the thermal recovery method. Recovered mercury is returned back to electrolysis. Also, the enterprise started recovery of mercury from solid waste, accumulated during reconstruction of the floors in the electrolysis building. There is no significant emission of mercury in this operation. Total production losses of mercury in the chlor-alkali facilities include losses with anolyte filtration slurry, wastewater, ventilation discharge, losses with products (caustic soda and hydrogen) and mechanical losses. Below is given assessment of such losses in 1997 and 2002. Losses of mercury with anolyte filtration slurry During filtration of alkalised anolyte following its additional saturation with evaporated salt, micro admixtures of iron and heavy metals, present mainly as hydroxides, are precipitated in the packing of the bulk filters. When the filtering packing becomes clogged, it is, from time to time, regenerated by a back flow of the wash brine. Then, insoluble admixtures are settled and filtered. The wash brine is filtered and returned to the anolyte cycle, while slurry is transported in special motor vehicles, equipped for carrying paste products, to the sites for disposal of waste classified as 2-4 class hazard (section N2 of the accumulation basins). Mercury discharged with such slurry is represented by water-soluble chlorides. Losses of mercury with anolyte filtration slurry made:
Losses of mercury with wastewater The total amount of mercury-containing wastewater generated at the enterprise makes about 100-130 thousand m3/year. In addition to wastewater from the electrolysis building and brine preparation bay, the wastewater includes spent solution containing FeCl3 from the shop where chemical de-mercuration equipment is installed. Wastewater is cleaned by the method of mercury precipitation as sulphide followed by settling and filtration. The filtered slurry containing basically mercury sulphide is stored temporarily into containers on a specially equipped site. In future, it is planned to send such slurry to a specialised mercury processing enterprise. Wastewater containing – after sulphide cleaning – not more than 0.05 mg/l of mercury is sent to the second stage of treatment by absorption with suspension RZh-1 (in Russian ÐÆ-1), after which concentration of mercury in water reduces to 0.005 mg/l. Treated and cleaned water is sent to a "dirty section" of the evaporation basins which makes part of the production waste disposal system (2 accumulation basins (sections 1 and 2) and 5 evaporation basins). The first section (with the area of 6.15 km2) receives wastewater (industrial, rail and sanitarian wastewater) after biological treatment, while the second (with the area of 2.11 km2) receives liquid and solid waste including brine treatment slurry. Evaporation basins (with the total area of 65.5 km2) receive wastewater from the accumulation basins as well as mercury-containing wastewater after sorption cleanup. The basins are located in uninhabited region, at a significant distance (several dozens of kilometres) from enterprises, dwelling houses and water basins, and represent – according to the RF Water Code – individual water bodies. The basin banks and beds are lines with water-resistant clay, 3-5 m thick. Along the basin perimeters there is a network of wells where permanent monitoring of the underground aquifers is organised. The two-stage system for treatment of wastewater used by the enterprise does not allow attaining the required standard of residual mercury concentration, equal to 0.001 mg/l. Total losses of mercury with wastewater to the ponds and with treated wastewater made:
Losses of mercury with ventilation emissions The system of ventilation in the electrolysis building is plenum, with outlets through the aeration lanterns. The lanterns have a height of 14 m. The flow rate of pumped-in air is 600,000 m3/h. The mercury concentration in the electrolysis building is 0.03-0.06 mg/m3. Beside the electrolysis room, also the hydrogen bay, the operator's room, the pump and the oven rooms as well as the slurry regeneration room are ventilated. The total losses of mercury with ventilation emissions from the electrolysis building and other premises made according to the enterprises official reports:
Losses of mercury with hydrogen All generated hydrogen is used within the enterprise, for production of hydrochloric acid and polyvinyl chloride resin. Since 1995, deep treatment of hydrogen fed to users has been done in three stages: sprinkling with chloranolyte, alkaline brine and followed by residual mercury sorption on activated carbon. Concentration of mercury in treated hydrogen fed to the users is 0.01 mg/l. Losses of mercury with hydrogen (actually with the manufactured products) made:
Losses of mercury with caustic soda Caustic soda is filtered from graphite and dispersed mercury. The spent filtration material is stored together with mercury slurry. Losses of mercury with caustic soda made:
Losses of mercury with chlorine Mercury entrained by chlorine gas is transferred to sulphuric acid used for its drying. The acid containing mercury is distributed among internal users of the enterprise. Losses of mercury made:
Losses of mercury with off-gases Treatment of off-gases from mercury and chlorine is made by absorbing the latter with an alkaline solution of sodium hypochlorite. Discharge of mercury with treated off-gases made:
Losses of mercury with wastewater, excluding wastewater from the electrolysis shop Wastewater sent to the biological treatment plant includes rain, industrial and sanitation wastewater of Kaustic OJSC (1900-2500 thousand m3/year), fed through a gravity system, and wastewater from outside (3,500-4,000 thousand m3/year), fed through the pressurised system. The content of mercury in the wastewater, equal, on the average, to 0.002-0.004 mg/l, is determined, above all, by the discharge of mercury settled in the soil, discharge with the surface rainwater as well as mercury dissipated by the wheels of the motor vehicles and footwear of the people over the territory of the enterprise. Also, this may include housing and industrial mercury-containing waste (basically luminescent lamps). Total losses of mercury with such wastewater made:
Mechanical losses of mercury Based on the amount of purchased mercury and the total recorded losses, mechanical losses of mercury calculated in this way made:
Such a significant reduction of mechanical losses in 2002, as compared to 1997, was due to reconstruction of the floors in the electrolysis building after 1997, as well as an improved quality of operation of the basic equipment. Summary on emissions Losses of mercury discharged into the air, water of the settling basins, buried or stored with slurry as well as mechanically lost mercury and lost with merchandise commodities are shown in Table 3.3. Table 3.3.Losses from Kaustic OJSC (City of Volgograd)
A significant reduction of losses of mercury in 2002, as compared to 1997, is also due to a higher level of catching of mercury and mercury-containing wastewater in the electrolysis shop after reconstruction of the floor, trays and pits. As it can be seen from the Table 3.3, mechanical losses of mercury for Kaustic Volgograd cell plant were 4.51 t. Annual mercury emissions to the atmosphere at Kaustic Volgograd cell plant were reduced in 2002 compared to 1997 as a result of the improved equipment servicing and general technical improvement of the facility. However there is no direct correlation between the values provided for 1997 and 2002 and the annual mercury emissions from the electrolysis shops calculated using airborne concentration and the total ventilation air flow rate, because other rooms and shops are also ventilated. Table 3.4 shows the dynamic of the average annual specific use of mercury over 1997 through 2002. Table 3.4. Specific use of mercury over 1997 through 2002
As can be seen from the shown data, reduction of the use of mercury was gradual – when the floors in the electrolysis building were rebuilt and measures were taken to improve technological discipline. Further reduction of losses can be attained, above all, through complete reconstruction of floors, trays and pits, increasing the trouble-free run of the electrolysers and a further improvement of the quality of operation of equipment and of the technological discipline. Reduction of losses of mercury with wastewater and slurry can be attained through organisation and putting into operation of plant for deep treatment of wastewater and mercury recovery from sulphide slurry and brine treatment slurry. Production stocks of mercury The total production stock of mercury is 229 tonnes, kept in the operating electrolysers. Mercury purchased for supplementing the electrolysers is practically used immediately in the production. The enterprise does not have any other stocks of mercury. Environmental condition Environmental monitoring of the condition of the air basin, made permanently at Kaustic OJSC and in the adjacent industrial areas, demonstrates that the average concentration of mercury in the air is close, in terms of absolute values, to the rated values of mercury emission to atmosphere, thus it is not exceeding the existing maximum allowed concentration. Thus, while data of 2002 shoed that the amount of mercury released to atmosphere with ventilation air and off-gases from the chlorine production facilities was 0.389 tonnes, then the total emission of mercury to the air, estimated on the basis of monitoring over its content in the air basin made 0.401 tonnes. Mercury sent with wastewater to the settling basins and evaporation basins does not make any significant input into the total content of the metal in the air basin, mainly because it is present in slurry as insoluble and non-volatile compounds. Infiltration of mercury into underground aquifers under the basins, as demonstrated by the results of the permanent monitoring of samples taken from a network of boreholes located along the basins' perimeters, is not identifiable which can be explained by a high degree of water inpermeability of the so called "chocolate" clays, protecting the basin banks and bottoms. At the same time, given the above mentioned fact that small amounts of mercury and its compounds are present in wastewater as mercury-containing wastewater, as was indicated in par. 4.2.8, and taking into account a significant magnitude of mercury losses in production, it should be acknowledged that mercury and its compounds can get into water basins and underground aquifers in the area adjacent to Kaustic OJSC. By assessment made by specialised geological organisations, there may be up to 500 tonnes of mercury inside the ground under the chlorine shop. It is not possible to make a strict estimate of the mercury amounts discharged to the air and water system from such reserves. Options for release reduction 1. The production enterprise is characterised by a stable condition and by a generally high operational discipline. 2. The technological production process ensures low losses of mercury with slurry from brine treatment and gives opportunities for further reduction of losses of mercury and its emissions to the atmosphere and water basins at the expense of available reserves for improvement. 3. Reduction of losses and discharge/emission of mercury can be attained through implementation of the following actions:
Kaustic CJSC (Sterlitamak) The electrolysis room is equipped with electrolysers 30M2 (manufactured by O. De Nora, Italy) and vertical amalgam decomposers, rated for 400 kA. Totally, 34 electrolysers are installed. Operation of the electrolysers is characterised by insignificant variations of the load for the electrolysis, due to unstable use of chlorine and caustic soda. In 1997, the electrolysers worked under the average load of 232 kA, while in 2002 this load was 273 kA. Preparation and cleaning of the brine for electrolysis is done by additional saturation of the anolyte cycle with evaporated salt, followed by filtration. Raw material used to produce chlorine and caustic soda includes salt from the underground brine and also return salt from the alkali evaporated during diaphragm electrolysis. Equipment of the units designed for final saturation and filtration of brine in the anolyte cycle is made of titanium and fibreglass, which allows 20-25 mg/l of active chlorine in the cycle. This excludes complete dechlorination of the anolyte through treatment by sulphide, and mercury in the brine is preserved without any loss with brine slurry. Brine after the electrolysers – after vacuum dechlorination, alkalisation and final saturation – is filtered through vertical sheet filters with a filtering layer based on pulp. Slurry after filter regeneration, containing insignificant amounts of mercury chlorides, is sent to the dirty brine collector, which also receives anolyte from the electrolysers shut down for repair. Slurry from the collector is loaded out and stored in the temporary storage site. Electrolysis is made in high-capacity electrolysers equipped with metal-oxide anodes. The design, equipment and technical conditions of the electrolysers on the whole meet the modern level of technology. However, performance of repair work on the electrolysers with high individual power increases the discharge of mercury vapours intro the air and of the mercury drops on the floor, which causes high mechanical losses of mercury and entrainment with the ventilated discharge. Therefore, maximum increase of the run period of the electrolysers without opening them is very important for this production enterprise. Over 1997 through 2002, actions were taken to increase the run time between repairs of the electrolysers, which now is 500 days. The technical decisions taken for further improvement of the design of the anode working part, the composition and the amount of active anode coating, and the organisation of an automatic voltage control system allows extending this period 2-3 times, however, their complete use is hindered by restricted funds. Also, the service life of gummed materials of the electrolysers' parts is not sufficient. Another result of insufficient run period between repairs of the electrolysers is a relatively high level of mechanical mercury losses and its entrainment with the ventilated air. Over 1997 through 2002, work was performed to reconstruct and improve the equipment, as well as to increase the technological discipline among personnel. This helped reduce losses of mercury at several production stages. In 1998-2002, trays and pits in the floor of the electrolysis building were reconstructed, which allowed reducing losses of mercury with wastewater and mechanical losses at the expense of collection and return of spilt mercury and slurry in the electrolysis building. Mercury is regenerated from slurry by thermal recovery methods in a special oven. There, a mixture of mercury-containing slurry of brine filtration and wastewater is sent, including also spent activated carbon after hydrogen treatment, off-gases, dechlorination wastewater and caustic soda filtration wastewater, as well as resin from the ion-exchange treatment of wastewater. Before this waste containing various amounts of mercury is sent for recovery, such waste is mixed in such a way that the total concentration of mercury in this waste should be optimum for the thermal recovery process. In 1997, the amount returned for electrolysis was 4.02 tonnes, while in 2002 about 8.2 tonnes of secondary mercury was returned. Production losses of mercury include losses with wastewater, ventilated discharge, slurry after recovery of mercury, losses with products (caustic soda and hydrogen) and mechanical losses. Losses of mercury with wastewater The total amount of mercury-containing wastewater was 48,000 m3 in 1997 and 73,000 m3 in 2002. All mercury-containing wastewater is collected in the interim tank wherefrom it is pumped for preliminary rough filtration and settling. After the settling, water containing 3.5 mg/l of mercury, on the average, is clarified, chlorinated, fine filtered in quartz filters, dechlorinated by activated carbon till the residual content of active chlorine becomes 30-50 mg/l; then, it is sent to ion-exchange treatment at three sequentially-connected absorbers. Spent resin, after flushing with water and hydrochloric acid, is stored on the site for temporary storage of mercury waste, wherefrom it is sent, from time to time, for thermal recovery in a mixture with other slurry. Concentration of mercury in treated wastewater made:
These values exceed the current standard of 0.001 mg/l. Treated wastewater is fed to the general in-house system for wastewater polluted with minerals, and then to the system of settling basins located outside the enterprise. These settling basins also receive conventionally clean wastewater from Kaustic CJSC including rainwater with no separate control of mercury in it. They also receive wastewater from three other enterprises. The share of wastewater from Kaustic CJSC makes about a half of its total amount. Totally, there are two settling basins with the volume of 2.1 million m3 each. They are equipped with stirring devices and a system of hydraulic insulation. Wastewater is filled into and pumped from both settling basins autonomously so as to maintain at the outlet of each of them an optimum level of outputted admixtures. Wastewater is discharged, after settling, into the Belaya River. The total amount of irrevocable losses of mercury with wastewater were:
This significant reduction of losses in 2002 was due to the use of a more effective sorbent (resin AB17-8 instead BP1-AP). Losses of mercury with ventilation emissions The system of ventilation in the electrolysis building is plenum, with outlets through the aeration lanterns. The lanterns have a height of 18 m. The flow rate of pumped-in air is 1.2 million m3/h. The mercury concentration in the electrolysis building was 0.018 mg/m3 in 1997 and 0.017 mg/m3 in 2002. The total losses of mercury with ventilation emissions from the electrolysis building and other premises made according to the enterprises official reports:
Reduction of losses of mercury was due to the use of measures aimed at increasing the run time between repairs of the electrolysers. Losses of mercury with hydrogen All generated hydrogen is used within the enterprise (for HCl synthesis, propylene heating ovens for epichlorohydrins production) or transferred to other users (the synthetic rubber enterprise, oil and chemistry enterprise). Deep treatment of hydrogen fed to the users is made by a sequential sprinkling with chlorine anolyte, alkaline brine and subsequent sorption of residual mercury by activated carbon HPR-3P. Concentration of mercury in treated hydrogen fed to the users is 0.003 mg/ m3. Losses of mercury with hydrogen made:
Reduction of losses of mercury in 2002 was due to improved design of the sorption column. Losses of mercury with caustic soda Caustic soda is filtered from graphite and dispersed mercury through a layer of activated carbon. The spent carbon is sent to the site for temporary storage of mercury-containing waste, and then for thermal recovery. The residual content of mercury in the filtered alkaline is 0.00002% by weight. Losses of mercury with caustic soda made:
A sharp reduction of losses of mercury in 2002 was due to introduction of measures enhancing technological discipline among personnel. Losses of mercury with chlorine No such loss is identified, since mercury compounds practically completely absorbed by water during flush of humid chlorine. Losses of mercury with off-gases Treatment of off-gases is made by sorption on activated carbon HPR-3P. The amount of treated off-gases was about 500 m3/h. Concentration of mercury in treated off-gases was not more than 0.0035 mg/m3. Losses of mercury with off-gases made:
A sharp reduction of losses of mercury in 2002 was due to improved quality of operation of the electrolysers (in particular, normalising the temperature conditions and flushing of boxes) and improved design of absorbers. Losses of mercury with thermal recovery slurry Slurry loaded from the thermal mercury recovery oven contains not more than 0.01% by weight of mercury. Such slurry is sent to the controlled site "Tsvetayevka", which includes a system of buried concrete containers with special protective coating. Losses of mercury with slurry made:
Mechanical losses of mercury They are determined by the difference between the amount of mercury purchased during the year and the amount of mercury losses accounted for the same year. Also take into account is the change in the total load of mercury into the electrolysers in comparison to the previous year. The last factor is important for the electrolysers 30M2, since their design allows using a broad range of mercury in the electrolyser-decomposer-pump system; however, when the load of mercury is below the optimum level it brings down technological indicators of the electrolyser operation. The above values were as follows (see Table 3.5). Table 3.5. Calculation of mechanical losses of mercury in 1997 - 2002 at Kaustik CJSC (Sterlitamak)
It should be noted that mechanical losses of mercury calculated as indicated above include also mercury-containing slurry accumulated in the contaminated brine collector and in settling basins for treated wastewater. Such slurry is accumulated over several years and then is sent for thermal recovery after planned inspections and cleaning of tanks and containers. In view of the fact that this process takes place within a time period when the total losses of mercury have also changed, separate estimation of amounts of mercury brought from the electrolysers and settled in the tanks or lost in the ground through non-tight floors is difficult to make. Losses of mercury emitted to the air, water, buried or stored with slurry as well as mechanically lost are shown in Table 3.6. Table 3.6 Losses of mercury at Kaustic CJSC (Sterlitamak)
A significant reduction of losses of mercury in 2002 as compared to 1997 was due to a targeted implementation of actions aimed at improving technologies for different production stages, increasing technological discipline and control of repair quality. This helped reduce several times losses of mercury with treated wastewater and merchandise products and reduce two times emissions to atmosphere and mechanical losses. At the same time, discharge/emissions for the last two categories remain insignificant, while their reduction will make it possible, in future, to exercise a significant impact on the value of the total mercury losses. This can be attained, above all, as a result of a substantial increase of the run time of the electrolysers without stops and repairs. At Kaustic-Sterlitamak cell plant annual mercury emissions to the atmosphere were reduced in 2002 compared to 1997 as a result of the improved equipment servicing and general technical improvement of the facility. However there is no direct correlation between the values of mercury emissions to the atmosphere provided for 1997 and 2002 and the annual mercury emissions from the electrolysis shops calculated using airborne concentration and the total ventilation air flow rate, because other rooms and shops were also ventilated. Production mercury stocks There is 204 tonnes of mercury in production – in the operated electrolysers. Mercury accumulated for the electrolyser supplementation and secondary mercury after recovery from slurry is practically used immediately to supplement for its loss in the electrolysers. Some amount of mercury, both as metallic mercury and as slowly soluble salts (sulphuric acid and calomel) is deposited in the precipitation accumulated on the bottom of the settling basins and wastewater clarifiers and the tank for collection of contaminated brine. The average time of storage is about 3 years. It is difficult to make a quantitative assessment of such stocks. The enterprise does not have any other mercury stocks. Environmental conditions The environmental department of Kaustic CJSC and the sanitary services of the city permanently control the content of mercury in the air basin at the enterprises and in the city of Sterlitamak as well as in water (at the control site in the Belaya River) where treated effluents are discharged (see table 3.7). Table 3.7 Content of mercury at the control site on the Belaya River, after the city (downstream of the point of discharge form Kaustic CJSC ), over 1999-2002*
* Data provided by the Environmental Department of Kaustik CJS ** Maximum allowed concentrations of mercury are: for potable water: 0.0005 mg/l; for fishery water bodes: 0.00001 mg/l. As can be seen from Table 3.6, the concentration of mercury in the Belaya River, beginning from 1998, has not exceeded the MAC for potable water ands for fishery water bodies. A rough estimate of the magnitude of mechanical losses of mercury over the entire period of operation of this enterprise suggests that the soil under the electrolysis building accumulates about 200-300 tonnes of mercury. Options for release reduction 1. The production enterprise is characterised by a generally high operational discipline with small variations of operational conditions at the electrolyser loads. 2. The technological production process ensures low losses of mercury with slurry from brine treatment, off-gases and products, insufficiently low losses with treated wastewater and comparatively high mechanical losses and losses into atmosphere with ventilation discharge. 3. The enterprise has potential for a further reduction of losses of mercury that can be attained through implementation of the following actions:
Sayanskchimplast OJSC (Sayansk City) The electrolysis building is equipped with electrolysers SDM-200/7.5 (Russian abbreviation) with metal-oxide anodes and vertical decomposers. The total number of electrolysers is 96, rated for 200 kA. In 1997, there were 34 electrolysers working, with the load of 140 kA; in 2002, this number was 60 with the load at 160 kA. Brine for electrolysis is prepared and cleaned by additional saturation of the anolyte cycle with clean evaporated salt, followed by a two-stage filtration on bulk and frame filters. Raw material used for production of chlorine and caustic soda is salt from the underground brine, which is first cleaned and then evaporated. Some tanks of the anolyte cycle are made from steel lines with acid-alkaline lines; some pipelines are from gummed steel. Condition of anti-corrosion protection of the anolyte cycle equipment, including the condition of the electrolysers, is unsatisfactory, and, thus, does not allow ensuring the required amount of feeding brine without a complete chemical dechlorination of the whole anolyte flow using sulphide treatment method. This results in losses of mercury with brine slurry as mercury sulphides as well as in complications in the operation of the electrolysers, bringing about high mechanical losses of mercury and its entrainment with ventilation as vapours. Slurry generated in the electrolysis building as well as other slurry rich in mercury are sent for thermal recovery of mercury. Actions performed during 1998 through 2002 to reduce losses of mercury were of partial nature and did not affect their magnitude. Below is given assessment of losses of mercury in 1997 and 2002. Losses of mercury with anolyte filtration slurry Brine slurry containing mercury sulphide is sent for burial in a specially equipped slurry accumulator together with other mercury-containing waste, including sulphide slurry from wastewater treatment. The useful volume of the slurry accumulator is 223,000 m3, the area being 4.3 ha. The height is 9 metres. The slurry accumulator bottom and banks are lined with polyethylene film, pressed by sand and gravel. Losses of mercury with anolyte filtration slurry made:
Losses of mercury with wastewater The total amount of mercury-containing wastewater was:
The content of mercury in untreated wastewater varied between 15-20 mg/dm³. Wastewater treatment is made by precipitation of mercury using the sulphide method followed by water evaporation. The mother solution evaporated to the NaCl concentration close to its concentration in a depleted anolyte is sent for supplement of the anolyte cycle while the water condensate is sent for additional treatment from residual mercury on the carbon sorbent. Treated wastewater is returned to production and used for flushing of equipment and preparation of working solutions. Excessive treated condensate is discharged to the rainwater sewerage system and then to the Oka River. Sulphide slurry from wastewater treatment is sent for burial together with brine treatment slurry. Concentration of mercury in treated wastewater, discharged to the sewerage system, made 0.016 mg/dm³ in 1997 and 0.0003 mg/dm³ in 2002. Volumes of treated condensate discharged to water bodies were not recorded. Content of mercury in the control site in the Oka River water was 0.00001 mg/dm³. Losses of mercury with treated wastewater cannot be estimated; however on the whole, given specific technological scheme and treatment depth, they are not high. There is no relative information about values of losses with slurry at the stage of sulphide treatment of wastewater, however, most probably, they make part of the losses with sulphide slurry of brine treatment. Losses of mercury with ventilation emissions The system of ventilation in the electrolysis building is plenum, with outlets through the aeration lanterns. The lanterns have a height of 22 m. The flow rate of pumped-in air in 1997 was 2.48 million m3/h, and in 2002 it was 0.68 million m3/h. The average mercury concentration in the electrolysis building air varied between:
The total losses of mercury with ventilation emissions from the electrolysis building and other premises made according to the enterprises official reports:
Losses of mercury with hydrogen The bulk (ca. 99%) of discharged hydrogen is emitted into the atmosphere through a 22 m high pipe. The remaining hydrogen is used for synthesis of chlorine hydrogen. Treatment of hydrogen is made on sorbent from activated carbon brand HPR-3P (Russian abbreviation). Concentration of mercury in treated hydrogen fed was 0.048 mg/m3 in 1997 and 0.0024 mg/ in 2002; the standard rate is 0.01 mg/m3. Total losses of mercury with hydrogen made:
Losses of mercury with chlorine No information is available on such losses of the enterprise. Losses of mercury with off-gases Treatment of off-gases is made by sorption on activated carbon HPR-3P (Russian abbreviation). Concentration of mercury in treated off-gases is within 0.003-0.0049 mg/m3, with the standard rate being 0.01 mg/m3. Losses of mercury with off-gases made:
Losses of mercury with caustic soda No information is available about such losses. However, given that filtration of caustic soda at the OJSC "Syanchimplast" is similar to other enterprises, it can be estimated on the basis of annual output rate. Estimated losses of mercury with caustic soda made:
Mechanical losses of mercury The following amount of mercury was purchased for the electrolysers:
Mechanical losses, calculated by the difference between the amount of purchased mercury and losses recorded for the above-indicated causes, were:
Amounts of mechanically lost mercury accumulated over more than 20 years, according to the information of the enterprise, are contained within a loose cover under the electrolysis shop. Tentatively, this amount is about 800-1000 tonnes. Production mercury stocks Total amount of mercury in the electrolysers is 171 tonnes. The enterprise does not have any other stocks of mercury. Losses of mercury emitted into the air, stored with slurry and mechanically lost into the ground under the electrolysis building, are shown in Table 3.8. Table 3.8 Losses from Sayanskchimplast OJSC, Sayansk City
Options for release reduction The data present show that, despite not quite satisfactory, as compared to other operating production facilities, values of discharge of mercury to air, water and losses with merchandise products, and, most probably, discharge to water, mechanical losses and losses with brine treatment slurry are unacceptably high. The total condition of production is unsatisfactory, and at present the issue is considered to convert the mercury method of production of caustic soda and chlorine into the electrolysis method with an ion-exchange membrane, followed by de-mercuration of the buildings and the ground, as well as extracting mercury from the ground. 3.1.5 Waste Dumps and the Environment around Shut-Down EnterprisesThere are seven shut-down production enterprises in Russia. With exception of two large enterprises (Usolyechimprom OJSC and Krebs at Kaustic OJSC), these are small installation rated from 1.3 to 20 thousands of caustic soda per year; such enterprises operated basically as part of wood pulp and paper enterprises. All such enterprises, except for Krebs, used as raw materials outside solid salt brought to the enterprises. Chemical dechlorination of anolyte was made by means of treatment of sodium sulphide with simultaneous precipitation of mercury sulphide. Mercury slurry from such enterprises containing more than 1% of mercury were sent, as a rule, for recovery to the Nikitovsky Mercury Enterprise; brine slurry was discharged to the slurry sites; graphite anode waste was disposed at the disposal sites; and wastewater after sulphide treatment and settling was discharged to the general sewerage system of the enterprises. Mechanical losses of mercury were recorded at all enterprises: mercury infiltrated into the ground under the electrolysis building. Amounts of mercury accumulated in the ground, on disposal sites and slurry accumulation sites, as well as discharged to water bodies are shown in Table 3.9; these are tentative values calculated using available information about activities of every enterprise, specific data about technological process used at every enterprise, data about total use of mercury and its losses through different causes, as determined during the surveys. The precision of such estimates is ±020%. Table 3.9 Mercury in soils, waste dumps and water bodies by shut down enterprises produced caustic soda and chlorine (closed within 1982-1998)
The assessment made has demonstrated that within areas adjacent to the enterprises that are shut down the environment contains significant amounts of mercury dissipated inside the ground under production buildings (basically as metallic mercury), in slurry accumulators (basically as mercury sulphide), in disposal sites (basically as metallic mercury) and in water bodies (basically as mercury sulphides). The amount of such waste is determined by the production capacity, the period of their operations and the level of mercury losses. The highest mercury pollution is typical of industrial areas in the towns of Usolye-Sibirskoye, Sterlitamak, Koryazhma and Novodvinsk. According to the available information, certain work is under way there to clean up the grounds within the vicinity of former production buildings from mercury. To minimise possible damage from mercury waste accumulated in these areas and prevent further dissipation of such waste, it is expedient to organise broader surveys to detail maps of waste location, levels of soil, air and water pollution with mercury and design actions for containment and preservation of waste. 3.1.6 SummaryTables 3.10 and 3.11 show summary comparative data based on the results of inventory of mercury discharge and emission to air, water, soil and products by the enterprises manufacturing caustic soda and chlorine in the Russian Federation using the mercury methods in 1997-2002. All mercury purchased during a year was used (for filling electrolyzers) during the same year at all the enterprises except Sterlytamak plant where electrolyzers are designed in such a way that average annual fluctuations of mercury amount are possible. Table 3.10 Mercury balance for chlor-alkali plants in the Russian Federation in 1997
* to closed water system (ponds-evaporators). ** the term "mechanical losses" is used here for all unaccounted losses Table 3.11 Mercury balance for chlor-alkali plants in the Russian Federation in 2002
* the term "mechanical losses" is used here for all unaccounted losses The data presented shows that over the analysed 5-year period all these enterprises significantly reduced the amount of mercury emission/loss to air and products although all these enterprises increased their production output. This reduction was possible due to the relevant targeted technological actions and improvement of general technological discipline among personnel. All enterprises, with exception of Sayanchimplast OJSC, substantially reduced discharge of mercury to the ground through mechanical losses and to the controlled sites used for disposal of such waste as part of mercury-containing slurry. At the same time, the mercury losses and emissions of mercury to the air at all enterprises should be further reduced. To do this, the enterprises have concrete technical solutions, but the assessment also indicates that there is a significant potential for reducing the releases by relatively simple improvements of management practices. Expedient implementation of such solutions is hindered only by a lack of required financial investments. Therefore, search of such funds to finance the above operations and to control the use of the funds for specific actions, observation of the agreed terms for their completion and assessment of their efficacy would facilitate a further significant reduction of mercury discharge and emission from the chlorine enterprises and improvement of the environmental conditions in the regions. The overall flow of mercury by production of chlor-alkali in the Russian Federation in 2002 is illustrated in Figure 3.3. Figure 3.3 Mercury balance for chlor-alkali production in the Russian Federation in 2002 and in 1997
In order to compare the data of Russian enterprises with other countries the Russian data are entered into the common OSPAR reporting table (OSPAR 2002) along with the reported data for French enterprises (see Table 3.12). This comparison shows that the specific release of mercury with treated wastewater and off-gases of the Russian enterprises are within the range of the French. This is connected with the use of measures to increase the depth of purification of such release. At the same time, losses with products are 2-3 times higher than at French enterprises. This indicates an insufficient purification of caustic soda from mercury in Russian enterprises. Losses with ventilation release are also high from electrolysis shops. These releases can be reduced only by maximum possible decrease of frequency and duration of stoppage of the electrolysers. Mechanical losses (unaccounted losses) of mercury at enterprises of the Russian Federation are either very low (Kirovo-Chepetsk chemical enterprise) or several times higher than in France (Caustic, Volgograd; Caustic, Sterlitamak), or extremely high (Sayanskchimplast). Losses of mercury as slurry that is not fit for regeneration at enterprises in Volgograd and Sterlitamak are similar to those in France, while in Kirovo-Chepetsk and Sayansk they are very high. This is related to specific features of outdated technological scheme that requires complete dechlorination of anolyte using sulphide treatment (in Kirovo-Chepetsk) or unsatisfactory protection of the equipment of the anolyte cycle against corrosion (Sayanskchimplast). Table 3.12 Losses form chlor-alkali plants in France in 2000, (OSPAR 2002) and the Russian Federation in 2002 3.2 Other uses of Mercury in the Chemical IndustryMercury chloride is used for production of vinyl chloride monomer (VCM) at four enterprises in the Russian Federation. The production is described in section 3.2.1. Metallic mercury has until 1998-99 been used in the production of vitamin B-2 (riboflavin) at two enterprises. Mercury containing wastes stored at the enterprises is described in section 3.2.2. Mercury sulfate (II) was until 2000 used as catalyst for production of cube (1-amino anthrachion) colours. Mercury-containing waste is briefly described in section 3.2.3. In the former Soviet Union mercury catalysts were used for the production of acetaldehyde, but this production facility was situated in Kazakhstan (Termitau town, Karaganda oblast). The environmental situation around this enterprise is discussed in details in the relevant references. 3.2.1 Production of Vinyl Chloride Monomer (VCM)Hydrocarbon used as raw material for synthesis of vinyl chloride, i.e. acetylene, is generated from calcium carbide or by a high temperature pyrolysis of natural gas (or oil; hydrocarbons). The produced purified acetylene dried to the residual moisture content less than 1.5 g/m3 is sent to the mixture where the pre-treated (purified) and dried hydrogen chloride is also fed. The ratio of acetylene to hydrogen chloride usually is 1.0:1.1. This mixture of gases is fed to the upper part of the reactor represented by a shell-and-tube heat exchanger; inside the inter-tubular space there is circulating a heat carrier while the tubes are filled with a catalysis represented by activated carbon with mercuric chloride HgCl2 (10-15%) deposited on it. The reactor is made from carbon steel; the height of the tubes is 3-6 metres, and the diameter is 50-80 mm. Usually 6-12 m3 of catalyst are charged to the reactor. Temperature in the reaction area is kept at 150-180 °C. After the reactor the reaction gases are fed to the packed column sprayed with hydrochloric acid to extract the entrained mercuric chloride. Then, the reaction gas is flushed with water and a solution of alkali in the columns to remove hydrogen chloride, acetaldehyde and carbon dioxide from the gas. After that, gas is "refrigerated" in the condenser cooled with brine so as to remove moisture, compressed in the compressor to 0.071-0.81 MPa and fed for rectification. The rectification system includes two tray columns: the first column serves to extract high-boiling admixtures, basically the mixture of 1.1- and 1.2-dichloroethane while the second column is used to remove high-boiling admixtures. The obtained rectification products passes through the column for drying of the final product, filled with solid caustic soda for final drying and neutralisation of vinyl chloride. The schematic diagram for production of vinyl chloride from acetylene using a mercury catalyst is shown below. Figure 3.4 Production of VCM using a mercury catalyst
Mercury chloride (HgCl2) is used only for preparation of the catalyst. The mercury chloride is either purchased from abroad (earlier from Spain, but now more and more from China) or, in part from the Russian enterprise NPP Kubantsvetmet CJSC. The production at this enterprise is further described in section 5.1. Table 3.13 shows data on the capacity of production of vinyl chloride from acetylene as well as the use of catalyst per year as well as the content of metallic mercury in it. In total about 15.5 tonnes of mercury was used for the production of catalysts in 2002. About half of it was obtained from recycled HCl whereas the other half was purchased. Table 3.13 Production of VCM from acetylene and use of catalyst
By the process the fate of the mercury is as follows: about 30% remains in the spent catalyst; practically all remaining amount goes with hydrochloric acid (about 70%); about 0.1% goes with off-gases and emissions; about 0.1% goes with wastewater. Spent catalyst is accumulated and then sent to Kubantsvetmet OJSC (Krasnodar kray, Russia) for complete treatment and extraction of metallic mercury. Part of it is turned into mercury chloride and sent back to the user. Hydrochloric acid with 0.05-0.1% of mercuric chloride is returned for recycling within the enterprises to make catalyst (about 8 tonne mercury). Partially, it is sent to users and used in metallurgic or oil and gas industries for treatment of wells. It is absolutely prohibited to use such hydrochloric acid in food and medical industries. By the application of the hydrochloric acid in the wells the mercury will end up in the wells. The hydrochloric acid used in well in total contained about 2.8 tonne mercury. Concentration of mercuric chloride in off-gases and wastewater from the VCM production is within the allowed norms. The overall flow of mercury by the production of VCM in the Russian Federation in 2002 is shown in Figure 3.5. Figure 3.5 Use of mercury in production of VCM in 2002 ( t Hg)
Spent catalyst is stored at the enterprises before it is disposed of for recycling. Table 3.14 shows data about the approximate amount of spent mercury catalyst at the enterprises, ready for processing at Kubantsvetmet OJSC. The elevated accumulated amount of spent catalyst is explained by the fact that the license for processing (treatment) of mercury-containing waste at Kubantsvetmet OJSC expired in 2001 and it took time to arrange a new license. In 2003 Kubantsvetmet OJSC was to start to treat the spent catalyst. Table 3.14 Approximate amount of spent mercury catalyst for reprocessing stored at the enterprises by the end of 2002
3.2.2 Former Production of Vitamin B-2Metallic mercury was formerly used in a production of vitamin B-2 (riboflavin) in order to generate the amalgam of sodium (Na), by means of which there is carried out a process of recovering the aldose from aldonolactone. In the Russian Federation synthesis of vitamin B-2 under this technology was carried out at the two enterprises: Belvitamins JSC (Belgorod city) and Sintvita SC (Bolokhov, Tula region). Both enterprises were closed within 1998-1999. Totally at Belvitamins JSC and Sintvita SC there were produced about 150 tonnes of vitamin B-2. Mercury consumption coefficient is 0.036 kg per kg of vitamin B-2. Using this coefficient, the total consumption of mercury for the process can be estimated at about 5.4 tonnes as a maximum. Mercury containing wastes of these enterprises were sludge with mercury content up to 5% of mass, as well as used sorbents from gas purification facilities. Additionally, at Sintvita as a sorbent there was used an activated carbon, modified by chlorinated sodium, and at Belvitamins JSC there was used a pyrolusite. Volumes of warehousing the mercury-containing wastes at these enterprises in 1988 are presented in the table 3.15. Table 3.15 Mercury-containing wastes from production of vitamin B-2 accumulated at the enterprises
In 1999, Kubantsvetmet CJSC received from Belvitamins JSC 22 tonnes of sludge for utilization. 3.2.3 Former Production of PigmentsMercury sulfate (II) was until 2000 used as catalyst for production of production of paints (1-amino anthrachion) by Khimprom JSC (City of Cheboksary, Republic of Chuvashia). The annual use of metallic mercury for this purpose was several tonnes. Waste from the production was processed at Kubantsvetmet CJSC (section 5.1). 3.3 Gold Mining Using the Amalgamation Technology3.3.1 History of Gold Mining in the Russian FederationThe gold mining industry came into being in Russia in the XVIII century. The first gold-copper Voitskoye deposit was discovered in 1737 in Karelia, and the first large ore gold deposit – Berezovskoye was stricken in 1745 in Urals (Benevolsky, 2002). By the beginning of the XIX century more ore gold deposits had been discovered, however the intense commercial gold mining started after striking of placer gold in Urals and Siberia in 1814. In the period 1816 to 1890, the placers have been found all over the south of Siberia and the Far East – between Urals and the Littoral. In the 70-ies of XIX century, the use of hydraulic technology of gold mining by means of hydraulic monitors was pioneered in Siberia. In 1896 the first dredge was constructed. Gold ore mining was recommenced after the improvement of gold ores processing technologies, in particular amalgamation technologies application. In the 40-ies of XIX Russia mined as much gold that allowed it to be the first in the world. Totally, before the revolution Russia had officially extracted 2,754 tonnes of gold (Foss, 1963), including approx. 3 tonnes mined illegally. In Soviet times gold mining was officially started in October 1921 pursuant to the Decree of Sovnarcom On Gold and Platinum Industry, which declared the state ownership for the deposits of these metals. In 1921-1925, 11 state gold mining trusts were established. In 1927 All-Union Joint-Stock Association SoyuzZoloto was set up. Since that time, all information concerning the gold production and sale on the world market and its official reserves had been considered to be the State secrete, and therefore now is available only as the expert assessments (Gold History). In 1991 the gold mining industry of Russia was decentralized and rearranged. 12 large regional associations were abolished and reorganized into several thousands (9,000 by 1996) gold mining enterprises, most of which were not able to survive in difficult economic conditions, and therefore in 2001 there were 639 enterprises of various ownership, with prevalence of small scale prospecting artels. 584 of these mines (or 91%) are small scale enterprises mining less than 500 kg/year with average year staff up to 100 people (totally extracting more than 44 t of gold). More than 1 t of gold was extracted in 2001 by 22 mines (totally - 78.6 t or 5.6% of total mining volume). (Gold - 2002). In 2000, 20 mines annually producing more that 1 t of gold each contributed 55% in Russian gold mining. In 2001 the same enterprises provided 80% growth of gold mining in the country (the State Report 2003). Such organizational set-up is not able to promote the economic efficiency of the gold mining activity. Small scale mines don't have enough financial resources to purchase modern equipment, introduce novel technologies, carry out the exploration works, and comply with the environmental requirements. Development of gold mining in Russia within 1890 - 2000 is presented in Figure 3.6. Click here to see the figure.Figure 3.6 Development of gold mining in Russia within 1890 - 2000 (Benevolsky, 2002) According to various sources, 11-12 th. t have been mined during 280 years since 1719 (the first documented data) (Foss 1963, Benevolsky 2002, Vyazelschikov 1963). The expert assessments related to gold mining for the different time periods (incl. ore, placer and complex gold) are presented in Table 3.6 (Benevolsky, 2002). The Figure 3.7 includes the gold mining data in Russian regions for the latest 10 years. Table 3.16 Gold mining in Russia (Benevolsky 2002)*
Note: the data for 2001 are entered by the author of the present report. Figure 3.7 Dynamics and structure of gold production in Russia in 1991-2001 The official data for 2001 says about 154,455 kg of gold mined in Russia, including 141,449 kg by gold-mining enterprises. However, according to the experts of GFMS (Gold Fields Mineral Services), gold production in 2001 in Russia amounted to 168 tonnes, i.e. ranks fifth in the world gold production. The discrepancy with official data arise from the fact that GFMS experts account a share of illegal gold production in Russia equal to their mind to 10-15% (GFMS 2002). The same amounts of illegal gold are confirmed by Russian experts, including the law-enforcement authorities (Aivazov, 2001). Presently, Russia comes second after Republic of South Africa with forecasted gold resources, and the third after Republic of South Africa and the USA with the balance reserves, and the 13th place is taken by Russia with the state gold reserves by the end of 2001, Russia has 7-8% of the world reserves of gold (the State Report, 2003). Gold deposits are situated on the considerable part of Russia – from the Baltic Gate in the west to the fold structure of the Eastern Chukotka (see Figure 3.8) Click here to see the figure.Figure 3.8 Location of main gold deposits, mining enterprises and gold placer areas of Russian Federation(Benevolsky 2002) 1 primary gold deposits; 2 gold-silver deposits; 3 enterprises located at the primary deposits; 4 enterprises located at the gold containing complex deposits; 5- enterprises located at the gold-silver deposits; 6 gold placer deposits 80% of Russian gold reserves in gold deposits are contained in ore and about 20% in placer deposits. Almost 29% of gold reserves are located in complex deposits, basically in copper pyrite and sulphide copper-nickel, and sometimes in polymetallic deposits. Russia is an only large producer of gold in the world, the greater part of the gold was formerly mined in placer deposits, although they contain a little bit more than 17.5% of the reserves (the State Report 2003, Goncharov 2002.). The recent growth of gold production volumes is conditioned by general change of gold mining structure in Russia: transition from development of placer deposits to the active placing of the ore deposits into operation. Until 1998, the placer deposits provided up to 80 % of gold. During the following years this ratio has been changed fundamentally, in 2001 the share of the ore gold deposits mining reached 40 % in the total gold mining volume, and since 2002 ore prospects are expected to provide more than a half of the gold output in the country (Goncharov, 2002). Today, more than 1,700 placer deposits are developed and more than 1,000 are prepared for development in Russia. 3.3.2 Gold Production from Gold-mining Wastes For the whole history of gold mining in Russia about 80-85 % (approx. 9 th. t) of gold has been mined from the placer deposits (Benevolsky 2002). Due to the intense mining of placer gold, the reserves depletion, as well as decrease of the exploration works scope, the explored reserves of placer gold have 15% reduced during the latest 10 years (Gold, 2003). This was the reason for the large gold-mining enterprises to more actively develop the ore deposits, and the small mining companies – to mine the cheaper "technogenic" gold, i.e. gold contained in dumps, tailings and schliches, large number of which in the old gold-mining areas are the secondary industrial (technogenic) deposits in a number of cases. The prime cost of the metal produced from the technogenic sources varies between 3.5 to 6.0 USD per 1 gram in gold equivalent and trends to cut down to its minimum at the 2nd – the 3rd year of dumps operation (Bauer et al., 2001). The urgent need for the technogenic placers and other gold containing wastes of gold-mining reassessment for the compensation of realizable reserves of placer gold is stressed in the Federal Program on Reproduction of the Gold Reserves in 1994-2000 (Orlov, 1993). However, today there is no state statistical inventory of potential reserves in the technogenic placers. According to different expert assessments, during the intense placer gold mining activity , about 11.9 billion m3 of rock mass has been being washed out. The overall forecasted reserves of gold in dumps constitute 3,300 t (with the given average content equal to 0.2 g/m3: pebble dumps 1.7, gravel tailings 0.2 and peat dumps 1,400 t) (Benevolsky). Table 3.17 presents the available data on gold production from technogenic dumps in several gold-miming regions of the Russian Federation. Table 3.17 Reprocessing of technogenic gold containing dumps in some Russian constituents (Benevolsky 2002)
Note: Chukotka – 1970-1993 period, other RF constituents – one year period. Data provided in this table may seem to look somewhat inconsistent due to the lack of official statistic reporting on gold deposits and gold extraction rates in Russia. Therefore the above table presents only partial data that were available at Benevolsky B.I. 2002. Such inconsistency of information on reprocessing of technogenic gold containing dumps can be explained very simple. In case a technogenic gold containing dump site is located at the territory of a gold mining company then the latter does not need to obtain a licence for gold extraction from this dump site and consequently it would serve as a kind of additional gold extraction reserve and companies prefer not to disclose such things. 3.3.3 Gold Mining with Mercury AmalgamationThe gold amalgamation technique based on selective wetting of the native metal particles with mercury has been an integral part of conventional technological flowsheet of gold ores and sand concentration for a long time. The long and intense use of this technology in the gold-mining areas caused the severe Hg intoxication of employees and environment. In this connection, the order of the Chief Department on precious metals and diamonds of Ministry Cabinet of the USSR, No. 124, December, 29, 1988, officially prohibited the application of mercury in dredges and washing equipment since 1989, and since 1990 in gold-extracting plants (GEP) and schlich-concentrating plants (SCP) (The order of 1988). After this, all works related to amalgamation technology improvement and design of equipment for gold containing products demercurization were stopped. Nevertheless, the need for such equipment and environmentally sound technologies on Hg extraction from gold containing products still exists due to the mercury contained in these products has both technogenic (secondary processing of placer deposits and stale tailings of GEF) and natural genesis (Mullov et al., 2001). Mercury consumption and losses with ores and sands amalgamation to the great extent depended on deposit types, feedstock technological properties, mining and dressing technologies. The Russian gold-mining history includes four phases of Hg-amalgamation technologies application, conditioned by technical and technological re-equipment of mining industry and gold mining plants in particular (Foss 1963, Rukavishnikov 1984, Report 2002):
In the former USSR times, when gold mining was under strict state control and management, the enterprises and regional administrative offices registered Hg consumption for all gold concentration operations. There were norms for Hg consumption and losses established. For instance, the designed Hg losses at sluice gold extraction were equal to 10 % due to amalgams washing away. Mercury consumption and losses at different amalgamation technologies (internal, external, on dredges, washing devices, and gold extraction factories) varied considerably. Analysis of the real Hg losses based on the historical records of some gold mines of the Far East carried out in 60-70-ies showed the range of 0.5-1 t per 1 t of gold mined (Koval at al 1997, Sidorov 1999). As indicated in the Table 3.18, relation of Hg consumption to the amount of gold produced has been changed significantly from year to year from (6-10):1 to 1:4. Before Hg-amalgamation ban, when the effective mercury-free technologies were widely introduced, Hg specific consumption was considerably reduced. According to official information, total irreversible losses of metallic mercury on dredges and washing devices in this period reached 6 t/year, in GEF about 3 t/year (The order 1988). However, to our opinion based on the tables 3.18 and 3.19 the official data is obviously underestimated. For instance, in the end of 80-ies the annual mercury delivery to Zabaikalzoloto Association (the Chita oblast) producing about 8 t of gold constituted approx. 2 tonnes. Hence, almost the same amount of mercury is irreversible released to the environment. The losses amounted to 250 kg of mercury per 1 t of gold, taking into account application of other gold concentration technologies mercury free gravity , flotation and cyanidation (Laperdina 1995). The state economic reforms of the latest 15 years, which lead to loss and inaccessibility of many archival documents in Russia, do not allow to make a correct statistical estimation of total amount of mercury used in the gold-mining regions. Table 3.18 Mercury consumption and losses at gold-bearing rocks amalgamation
Note: Information sources 1 Order of 1988; 2 Myazin et al 1997A, 3 Polkin 1987, 4 Zamyatin et al 1975, 5 Vyazelshchikov et al 1963; 6 Koval et al 1997. Table 3.19 Hg and gold content in the gold mining wastes
3.3.4 The Current SituationMercury contamination of traditional gold mining areas of Russia, as in all gold-mining areas of the world, is very urgent and poorly known problem. Scope of Hg contamination and its effect in different territories are not thoroughly investigated. However, it can be stated with certainty, that all traditional gold mining areas shown in Figure 3.7 have different extent of mercury contamination, which is not localized as a rule. With the introduction of the effective gold mining technologies, the same sites of rich placer deposits were repeatedly washed up again, with subsequent mixing of mercury-containing dredges and hydraulic monitors dumps with the washed-out rocks, which resulted in their distribution all-over the bigger territory. The point sources include abandoned and operating tailing dumps of extracting and concentrating plants, gold-receiving offices. The industrial and residential areas of old gold-mining enterprises are often either transferred from the worked-out territories or gradually destroyed. Restoration and conservation of the contaminated gold-mining sites have not been planned and carried out earlier, therefore the destroyed tailing dumps and exhaust schliches with high Hg content cause the severe environmental pollution. As the location of the old placer gold mining sites can not always be found based on historical records, the assessment of mercury contamination of the traditional gold mining areas requires conduction of the expensive field and desk studies. The local, but isolated from the gold-mining areas, sources of mercury contamination are the refining plants. In present, there are five main sources of mercury release from gold mining activities, quantitative characteristics of which depend on deposit type and gold reserves, duration and intensity of the deposit mining and mercury use in technological operations: 1. Atmospheric emission of Hg from dumps, tailings, contaminated soils, as well as its washing-out and contamination of watercourses, soils, water and terrestrial environment. 2. At present widely applied re-processing of the secondary industrial placers, as well as processing of tailings and schlich concentrates of ore and placer gold. 3. Continued illegal mercury use for gold-bearing concentrates and sands extraction. 4. Mining of the gold deposits with natural increased mercury concentration. 5. Refining of gold-bearing concentrates with the increased natural or industrial mercury content in the refining plants. Let's consider these mercury release sources in detail and try to assess their impact: Dredges and hydraulic dumps, tailings, schliches, contaminated soils. The wastes of placer gold mining constitute the major share in this group of sources. According to the expert assessment (Benevolsky 2002), about 11.9 billion m3 of the rock has been washed out during the period of intense placer gold mining. The available data (see Table 3.19) shows, that Hg content in dumps varies considerably from 0.05 to 2000 mg/kg. Dumps' sites with severe mercury contamination are more localized and less scaled. Therefore, the approximate average Hg content in dumps is significantly lower and can be estimated as 0.2-0.5 g/m3. Given the above indicators, the total mercury amount in placer gold mining wastes ranges between 3,000 - 6,000 t. It is very difficult to assess the release of both industrial and natural mercury contained in dumps and tailings, as it is partly isolated under the layer of the mined-out rock or in the basement of dredge pits. Moreover during the long-term storage technogenic and natural mercury undergo physicochemical and chemical transformations. Therefore, the mineral composition of mercury compounds, composition and properties of gold and other metals amalgams, concentration of liquid mercury in gold mining wastes are unique indicators for each site, and they are extremely important for Hg environmental emission and impact assessment, as well as for development of the environmentally sound technologies of gold- and mercury-containing wastes processing and remediation of the contaminated areas. Such kind of works are carried out in some Russian institutions. For example, IRGIREDMET staff investigates the composition of mercury mineral forms in the re-processed rocks, in order to increase the efficiency of gold and mercury extraction. The following composition was determined for one of the mining sites (in %): calomel (Hg2Cl2) - 51.8; mercury oxide (ÍgO - 1.1; native mercury (Íg) as the amalgamated gold - 25.1; cinnabar (ÍgS) - 6.7; mercuric chloride (ÍgC12) and water-soluble mercury types - 1.4; selenides, tellurides and other "persistent" types of mercury -13.9 at the overall concentration of Hg in the rocks equal from 30 to 100 g/t. (Mullov et al., 2002). The specialists of Chita Polytechnic University have investigated the composition and properties of gold amalgams, in order to develop effective magnetic-gravitational technologies of industrial wastes processing (Myazin et al., 1997A, 1997á). Re-processing of secondary industrial placers The extensive re-processing of secondary industrial placers, as well as processing of tailings and schlich concentrates of ore and placer gold (see Table 3,19) have lead to extraction of Hg buried in dumps, pits, , its conversion into the active migrating state and release to the environment with atmospheric emissions (thermal treatment of concentrates, mercury degassing from dumps etc.) and wastewater discharges. The licensing agreement on mining of such placers doesn't take into consideration a high industrial Hg content in the processed sands, and therefore the dissemination and extension of mercury contamination scope is not controlled. In spite of the currently developed and applied technologies of industrial feedstock processing with extraction of both gold and mercury, small scale enterprises with low revenues will likely to use cheaper technologies with only gold extraction, i.e. use burning of the amalgamated gold without Hg vapours condensation at the final phase. In case the environmental control over licensing and further mining of such gold- and mercury-bearing secondary industrial deposits is not strengthened, a half of mercury presently contained in dumps and wastes (3,000-6,000 t) is supposed to be released gradually to the atmosphere and water bodies. The scarce data presented in the table 3.18 indicates that a share of secondary industrial gold for various regions constitutes 1-5% of the total amount of the gold extracted. In general, a share of technogenic gold in Russia can be approximately estimated as 2-4 %, therefore the amount of secondary industrial gold extracted in 2001 may be equal to about 2,800-5,600 kg. Taking into account the average content of gold in the industrial wastes equal to 350 mg/m3 (see Table 3.18), the volume of re-processed industrial wastes can be estimated as the following: 2,800 kg : 350 mg/m3 = 8 million m3; 5,600 kg : 350 mg/m3 = 16 million m3. Given the amount of the re-processed industrial wastes as 8-16 million m3 and average Hg content as 0.2-0.5 g/m3, the total share of industrial mercury in this volume might make up from 2 to 8 t. About 15-20 % of this amount could have been utilized using modern technologies (see Annex 1), however the basic amount of previously accumulated industrial mercury (approx. from 1.5 to 6.5 t) could be released in 2001 in the gold-mining sites and surrounding environments. It is roughly estimated that 60% of this amount was emitted to the atmosphere, about 20% (0.3-1.3 t) accumulated in waste and the same amount, 0.3-1.3 t, released to water bodies. Mining using the amalgamation method The illegal and therefore uncontrolled mercury use in amalgamation operations of gold-bearing concentrates still persists, in spite of the official ban (Laperdina, 1995, Report 2002). Major users of mercury are small-scale enterprises, which do not have enough finances to purchase the expensive processing equipment and use gold schliches amalgamation to increase gold extraction efficiency. The similar picture is observed in Kazakhstan, where gold amalgamation and mercury burning at the illegal gold mining by individuals are carried out at homes using much more primitive operations (Kirillova, 2002). As an illegal use of mercury is punishable as violation of environmental and labour legislation, the information on such kind of Hg use is of course not available. Very rough estimation of current Hg use in gold amalgamation process can be made using the existing data of Russian gold production structure in 1999 (see Table 3.20). In that year, the gold was produced by 639 enterprises, and in 2001 566. It is assumed that gold structure had been changed a little by 2001 compared to 1999 and the data for this year is used for further estimations. Table 3.20 Distribution of gold miners in 1999 (Kolmogorov 2000, Benevolsky 2002)
In 2001 gold mining enterprises produced 141,500 kg, including ~ 26 (11.2+14.8) % or ~ 37 t mined by small enterprises (<100-300 kg/year). In case the mercury was used in the final refining of this gold, and Hg estimated (Roslyakov et al., 1995) norm consumption are equal to ~10 % per 1 kg of the mined gold, the total consumption of mercury in amalgamation will be equal about 3.7 t/year. Taking into account the range of uncertainty of Hg use during gold production by small enterprises (20-40 t of gold) and loss percentage (10-20 % and more), the total Hg consumption at gold amalgamation may vary between 3-8 t. The mercury extracted during gold- and mercury-containing industrial wastes can most probably be used for these purposes. The value in the middle of the range 6 t of Hg/year was informally presented by a person related to secondary mercury production and by quite clear reasons not wished to provide an official information on mercury supplies to gold mining enterprises. Mining of gold-bearing deposits with the increased content of mercury in ores, sands, bearing stratum. Mercury concentration in the gold ores can reach 300 g/t (the frequently occur level is 1 g/t), and 10-20 g/t in endogenous haloes of deposits (the frequently occur level is 0.1-0.4 g/t) (Roslyakov et al., 1995). Due to mining of these deposits the dumps of bearing strata contain quite high concentrations of mercury, and are non-localized sources of mercury releases. According to the expert assessment (Roslyakov et al., 1995), 1 tonne of gold mined gives about 100 kg of natural mercury contained in dumps and released to the environment. Given the 1:10 ratio of mercury and ore gold mined in 2001, the approximate amount of the extracted mercury can be estimated as the following: (141,449 kg õ 40%): 10 ≈; 5.6 t of Hg. Taking into consideration an uncertainty of the calculated value, it would be more correctly to show a range of releases as 4 – 8 tonnes. It might be assumed that 20% (0.8-1.6 t/year) of this amount is released to the atmosphere, 10% - to aquatic environment, 70% (2.8-5.6 t/year) – to tailings and waste. In the USA, 5-15 t of the accompanying mercury was recovered during complex gold-ore rocks processing at several (below dozen) enterprises in the western part of the country – in California, Nevada and Utah – with the key aim not to obtain mercury, but to prevent mercury releases to the atmospheric air and aquatic environment (Mercury production 2002). Unfortunately in Russia all accompanying mercury is released in the environment with mining, processing and refining wastes. Refining of the gold-containing concentrates with the increased natural or industrial concentration of mercury at refining plants. By the 1st of January 1999 the following Russian enterprises were licensed to refine the precious metals: Prioksky non-ferrous metals plant (Kasimov town, Ryasan oblast Region); Novosibirsk refining plant (Novosibirsk city); Schelkovsky secondary precious metals plant (Schelokovo town, Moscow Region); Krasnoyarsk non-ferrous metals plant (Krasnoyarsk city); Yekaterinburg non-ferrous metals plant (Yekaterinburg city); Kishtim copper-electrolytic plant (Kishtim town, Chelyabinsk oblast Region); Kolimsky affinage plant (Hasin town, Magadan oblast); Uralelectromed' JSC (Verkhnaya Pishan town, Sverdlovsk oblast); Norilsk Mining and Metallurgical Company (Norilsk city, Krasnoyarsk oblast); ONIX Concern (Moscow) (Tereshina, 2000). According to the official data, the Hg content in concentrates incoming at refining plants (up to 1988) was equal to 0.2-4.0 g/t (The order 1988). The severest mercury contamination source was likely the oldest of the above enterprises – Novosibirsky affinage plant, which refined about 60% of the mined gold till the beginning of 90-ies (Tereshina, 2000). Taking into account the refining of gold-containing concentrates and schlich gold with the increased mercury content, the surrounding environment of the plant has an industrial mercury halo in soils (0.03-18.9 mg/kg). Concentration of gaseous mercury in the soil air 100 times exceeds the local background (Roslaykov, 1995). In present, the increased Hg content in the concentrates incoming to refining might be caused both by natural factors – high Hg concentration in the gold ore, which is conserved just as in cyanic sludge, and by its previous direct use (mining technogenic placers and tailings) and current illegal application. At present it is not possible to assess the total Hg release at the refining of gold-containing concentrates, as the proportion of various concentrates to be refined (schliches, bullions, cyanic sludges etc.) and their Hg content is not known. Recently the current amounts of Hg releases due to the gold mining have been assessed (Roslyakov et al., 1995, Yagolnitser et al., 1995). However these estimates were quite rough and were performed based on the former gold-mining structure and technologies (gold placers mining prevailed). For example, the approximate annual mercury releases to the environment of Siberia amounted to 34.4 t. Therefore the shares of atmospheric, water and terrestrial (dumps, tailings, soils) releases were supposed to be equal. Summary Based on historic records, references and official data, a rough estimation of total Hg releases to environment during different time periods, including 2001 can be made (see Table 3.21, Table 3.22). For the whole history of gold mining in Russia, 6,350-6,690 t of Hg might have been released, including 6,125-6,660 t with losses during amalgamation and 230-245 t from accompanying extraction with gold-bearing ores and rocks. In 2001 Hg releases from gold mining in Russia could total from 10-20 t, including 4-6 t of natural mercury, 3-8 t from current amalgamation and 1.5 to 6.5 t from the gold mining technogenic wastes treatment. The presented estimations are very approximate. Unfortunately the authors of the present report have no materials for more correct assessment. Table 3.21 Approximate estimation of Hg releases from the gold mining in Russia
*the estimation is based on average placer gold output formerly equal to 80 % of the total production of gold mines. Table 3.22 Approximate estimation of Hg releases from the gold mining in Russia in 2001
* The estimate is included in the section of mobilisation of mercury by non-ferrous metallurgy in section 4.4. Note, that due to specific climate conditions in the most of gold miming areas of Russia (low average annual temperatures, permafrost, short open water period etc.), it is rather difficult to use Hg release ratios (atmospheric, water and terrestrial environments) determined for the tropical climate. Moreover, unlike these countries, Russia used and still uses more productive dredges (with large digging depth and buckets capacity (up to 600 m3) and hydraulic processing facilities, which together with severer climate allows to bury ("conserve") a considerable part of mercury in anaerobic conditions under a layer of processed sands. Mobilization of mercury from such secondary industrial placers is possibly during the re-mining. Taking into account all above-mentioned, it is quite difficult to estimate ratio of Hg release to various environments. Based on the data obtained for tropical climate (Lacerda 1997, MMSD 2002, Hylander 2001), and given the specific climatic conditions of Russian gold mining areas, it cab be concluded that during industrial use of mercury at gold mining and recycling operations (before the official ban), Hg releases to aquatic, water, air and soil environments were almost equal. In our days, when mercury is mainly used by small enterprises, the amounts of Hg releases may be close to the estimated values for tropical climate: 2/3 to the atmosphere, 1/3 to soils and water bodies, 2-8 % buried with the processed sands. The estimations involved the following ratios of Hg distribution in the environment: 70% - air; 20% - water; 10% - process sands and slimes. It should be noted, that the reliable data can be obtained only through field observations. 3.3.5 Mercury Contamination of Gold-mining Areas of RussiaToday the mercury contamination sources in the gold-mining areas are dumps and tailing dumps, as well as bottom sediments of natural and industrial water bodies. They cause pollution of natural ecosystems and residential areas in the gold mining impact zones. The pollution level is very poorly investigated. Some data on gold mining areas of Siberia, Far East and Urals are presented in (Alakayeva 1999, Laperdina 1999, Report 2002, Kutliahkmetov 2002). According to the investigations results, the most severe mercury contamination is observed near gold extraction plants, where mercury was directly used in technological operations. For example, it was determined, that Hg content in their surrounding environment might 4-100 times exceed maximum permissible concentration (MPC). The following maximum concentrations of mercury have been detected: in soils – 18.9 mg/kg (9 MAC), total concentration in groundwater - 32.8 μg/l (65 MPC for drinking water), in natural watercourses – 40 ng/l (4 MPC for fishing water bodies), in bottom sediments – 54.2 mg/kg. At the sluice amalgamation on dredges and amalgam burning, Hg vapours content in the air might 50 times exceed the mean-shift MPC (250,000 ng/m3). Extremely high concentrations of Hg - 1,000-2,000 mg/kg (50-100 MPC for soils) are registered in concentration tailings and contaminated soils near processing and concentrating plants. In some regions (Krasnoyarsk, Chita, Blagoveschensk, Khabarovsk oblasts ) technologies on such industrial wastes re-processing with gold and Hg extraction are developed and applied. The obtained data shows, that severe climate typical for most Ural, Siberian and Far Eastern gold-mining areas inhibit some chemical, biochemical and biological processes promoting more localized mercury contamination compared to similar pollution points in the countries with tropic climate. Nevertheless the investigation of specifics of Hg behaviour in terrestrial and water ecosystems of seasonal frosts and permafrost zones, and metal methylation - demethylation processes in particular, requires execution of expensive laboratory and field studies. 3.4 Dental Amalgam Fillings3.4.1 Use of Mercury for Dental AmalgamsAmalgams (silver and copper) have been applied in stomatology since 1819. In 1971 the Ministry of Health of the USSR prohibited to produce copper amalgam containing up to 65% of mercury. This prohibition was caused by significant disadvantages of copper amalgam fillings and hygienic hazard of mercury. New types of filling material are constantly discussed in Russian dental scientific publications, but the certain amount of silver amalgam is still used and is expected to be used wider as durable and long-lived material. Today in Russia about 30 million teeth are filled annually, 7-8% of which with amalgam fillings (data of the Department of medical and economic investigations in dental service of SRI of social hygiene, economy and health management named after N.F. Semashko RAS). These estimations are confirmed by the experts of the Central Dental Scientific-Research Institute of the Ministry of Health of RF. Some contradictory information has been obtained as regards the mercury content of the fillings. According to some experts the filling contain 7-8% mercury, but the major mercury amalgam producing facility (mentioned below) states that the mercury content is about 50%. The mercury content of fillings used in Western Europe is 40-50% (Floyd et al. 2002). Thus, the mercury containing amalgam fillings annually used by Russian stomatologists amount to 2.1-2.4 million fillings a year. Consumption of mercury for one filling is equal to 350 mg in average (based on information from Russian manufacturer and Floyd et. al. 2002), i.e. about 700 kg of mercury is annually used for 2 million Fillings, which are finally release to the environment. Mercury used for amalgams is both produced in Russia and imported. The major mercury amalgam production facility is Stomachim CJCS in Saint-Petersburg. This enterprise annually supplies up to 500,000 capsules for amalgam making in "Amadent" capsules. Such amalgam is ready for use in dental clinics without additional components. The rest amalgam is imported. 3.4.2 Mercury Releases from FillingsHeating of the filling material on the open fire (that was plasticized in Russian clinics) always promoted evaporation of mercury, concentration of which was much higher than MAC. Many Russian investigations indicate high concentration of mercury in the indoor air of dental clinics – from 20 to 440 μg/m3 – walls' plasters, floor base materials. Let's take for example the data on mercury vapours concentration in dental rooms' construction materials (see Table 3.23). Table 3.23 Mercury containing samples of construction materials of dental rooms (Kataeva V.A., 2002)
A complex of measures aimed at dental clinics personnel protection from mercury vapours impact is envisioned in the relevant Sanitary Rules of the USSR Ministry of Health, 1984. These Rules /p.5.10/ implicate installation of air treatment facilities for mercury removal to prevent atmospheric air pollution with amalgamator's emissions. Nevertheless, such facilities do not exist, and presently there are no local treatment facilities installed in dental clinics, thus the mercury containing fillings' residuals and the extracted teeth go to the dumpsites with the general flow of mixed wastes. Taking into account that 10 years ago amalgam fillings constituted about 60% of the total amount of fillings, and the average lifetime of a filling is 10 years, the following releases with extracted teeth are possible today: 18 million fillings õ 350 mg = 6.3 t/year. In general the dental clinics are not equipped with filters and the main part of the extracted fillings will end up in the sewer. A part of the amalgams may be disposed of with municipal solid waste e.g. with lost teeth. Besides, the certain amount of mercury is released during cremation. The crematoriums are available only in four Russian cities - Moscow, Saint-Petersburg, Ekaterinburg and Nizhny Tagil, and are being built now in four more cities. Up to 2 million people die in Russia each year, 7% or 140,000 people are cremated. If it is assumed that the release by cremation is similar to the amount released in Western Europe of 350 mg per person cremated (Floyd et. al 2002) up to 50 kg of mercury is released annually. Assessment of distribution of mercury releases with cremation between atmospheric air, terrestrial and water environments can be presented in accordance with estimations of WS Atkins /1998/, except releases with fillings incineration, as there are only several incineration plants in Russia. Very few amounts of mercury are recycled. Therefore, it is supposed that the major quantities of mercury – up to 6 t/year - presently go to the sewer or to landfills/dumpsites, and this amount will decrease from year to year due to reduction of the number of amalgams fillings. As it is mentioned above, the releases of mercury to the atmosphere with cremated people constitute about 50 kg of mercury per year and this amount will 10 kg increase when new crematoria are operated. 3.5 Thermometers3.5.1 Production of Mercury ThermometersMercury thermometers are devices used to measure temperature; their operation is based on alteration of properties of metallic mercury used as thermometer liquid. Several groups of mercury thermometers are known (including medical, laboratory, technical thermometers, petroleum product testing thermometers, thermometers for agriculture, and special and contact-free thermometers) that can be used to measure temperature from –39 to +750 °C. Some types of technical (special) thermometers use a fusion of mercury and thallium as thermometric liquid, which allows decreasing the lower limit of measured temperature to –60 °C. Table 3.24 gives a brief characterisation of the basic groups of glass mercury thermometers manufactured in Russia. Table 3.24 Main groups of mercury thermometers manufactured in Russia (Nomenclature Reference Book ..., 1993; OJSC "Termopribor", Catalogue of Products ...; Report on the Research Work on the Topic "Studying the Nomenclature ...", 2000)
* The Catalogue of Products of Termopribor OJSC includes more than 60 brands of mercury thermometers, many of which are made in different models and/or as a set of items; ** Approximate limits. At present, the OJSC "Termopribor" is the only manufacturer of mercury thermometers in Russia (located in the town of Klin, Moscow Oblast), which is the successor of the Klin Thermometer Plant, which manufactured its first products in 1956*. At its peak years, the Klin enterprise manufactured up to 100 names (types) of mercury thermometers on a mass scale, as well as mercury switches and breakers, using up to 100-130 t/year. In 1990, the use of mercury at the plant was 93.2 tonnes (Report on Research on the Topic "Analysis ...". 1999). In the recent years, the scope of production and, hence, the use of mercury at the OJSC "Termopribor" has bees permanently decreasing, however since late 1990's these figures started to grow. In 1998-2002, up to 97-98% of products manufactured by the OJSC "Termopribor" included medical use thermometers; the remaining part included industrial (technical) thermometers (Table 3.25). Manufacture of mercury barometers, manometers and switches at the enterprise has been terminated completely (due to lack of demand). Now, the enterprise has a special shop for processing rejected products, contaminated broken glass, soft waste; they are subjected to de-mercuration at the modernised plants UDL-2m. While it is possible to agree with the arguments that mercury mechanically lost in technological processes, collected by forepumps (from the mercury traps) and then – after cleaning – returned to production, then the argument stating that "rejected products and soft waste are subjected to de-mercuration and the generated mercury is returned to production" is doubtful. Nevertheless, we will assume in the following calculations and estimates that the de-mercuration plant modernised by the enterprise specialists allows producing secondary mercury that, following its cleaning, is again returned to production. Manufacture of thermometers is mass-scale (conveyor) or batch production. Both types of manufacture are based on technological process of targeted differentiation, separation of mercury-related operations from non-mercury operations and mechanisation of mercury-relation operations. To this end, the Klin enterprise has special mechanised mercury facilities, including a bay for mercury cleaning, its transportation to installations that fill mercury into thermometers, and high-capacity mercury filling installations (MFI).* Mercury thermometers are mainly manufactured in the so-called special mercury building, which includes the bay for mercury cleaning, the shop of medical thermometers and the shop of industrial thermometers (at present, the shop of special thermometers is not operated). Generally, the process of manufacture of mercury thermometers includes three stages. The first stage includes mercury cleaning; the second stage includes manufacture of the glass part of the thermometers and filling of mercury; and the third stage includes graduation of the scale (thermostatic process). Table 3.25 Manufacture of thermometers, use of mercury and generation of waste at the Termopribor OJSC in 1998-2002
Table 3.25 (continued) * Primary actual data are given as provided by the Administration of Termopribor OJSC; ** Since 1999, the enterprise has been operating plants for de-mercuration of mercury waste (decontaminated broken glass is now taken to the municipal dumpsite; before, it was placed at the enterprise waste field, now closed); *** Dissolved mercury forms (other mercury is not identified by analysis); **** Data marked "no confirmed data" (further only calculated data were used); ***** Cotton cloth, wool, etc. (first subjected to de-mercuration, then, probably, taken to the municipal dumpsite); ***** Data marked "metallic mercury is captured by mercury traps and then returned to production"; ****** Data marked "rejected products are subjected to de-mercuration; the generated mercury is returned to production" (judging by the amount of generated broken glass, the share of rejected products is rather high, probably making up to 15-20% of the total manufactured thermometers, which is about 1.2-1.6 million thermometers a year during the reported period; it should be emphasised that Termopribor OJSC tests and checks each manufactured thermometer, unlike for example thermometers supplied to Russian from China where only 1 products per 1000 is tested). At the cleanup bay, metallic mercury is fed to a special tank, wherefrom it is supplied, by a pipeline, to the chemical cleaning bath; then by a pipeline it is supplied fore vacuum distillation and then to filtration (a system of filters is used, which allows a very fine cleaning of metal). After such preparation mercury is fed via a pipeline (suing pumps) to the shop of thermometers (to the so-called reception tanks located in the thermometers filling bay). From the reception tanks, a predefined amount of metal (up to 150 kg) is fed by gravity to the MFI; an insignificant part of it is used for parallel filling of several thousands capillary pipes; the rest of the mercury is returned by the pipeline to the initial tank located at the cleaning bay (for a new cycle described). In the most active period at the enterprise, the amount of returnable mercury used daily in the technological process reached 8 tonnes. During the technological process of manufacture of thermometers, direct manipulations with metallic (otherwise, "open" mercury) include the following operations: filling of thermal ampoules with mercury; removal of excessive mercury; checking of the scale; soldering of capillary and the graduation operations cycle built on the principle of selection of ready scales according to the thermometer scaling. Then all thermometers are tested and checked. Following checking, standard products are transported to the warehouse of finished products while rejected products are sent to the disposal shop. This shop receives contaminated broken glass and other mercury-containing waste. During technical operations with open (exposed) mercury its vapours get to air of the production rooms. In 1964, the Klin enterprise started the shop for cleanup of ventilation emissions of mercury vapours; the main equipment of this shop includes several absorbers (each of them includes up to 36 tonnes of pyrolusite). Before this shop started its operation, only ventilation emissions from the shops where "open" mercury operations were carried, had been cleaned; after this all emissions of this enterprise have been cleaned (Petukhov, Konovalov, 1973). The bulk of emissions from the shop of cleanup of ventilation emissions are emitted through the stack 62 m high. At present efficacy of operation of the absorbers is 83% on the average (pyrolusite filled into the absorbers has never been replaced, but rather loosened from time to time). Residual emission of mercury to atmosphere (after cleaning) in the mid 1980's was 150-190 g/day (55-69 kg/year), while concentrations of mercury vapours in air reached 0.05-0.1 mg/m3 (Methodological Recommendations ..., 1989). In the first half of 1990's, concentration of mercury vapours in the air of the working room at the OJSC "Termopribor" was within 0.02-0.05 mg/m3 (Stepanova, 1994). Now, concentrations of mercury vapours are measured in 25 points of the mercury building once a week (about 1,300 measurements a year); as a rule, in about 10-20% of cases the levels of mercury vapours exceed the maximum single MAC (maximum allowed concentration) within the working area (= 0.01 mg/m3). Some year ago at the enterprise in Golynki, concentrations of mercury vapours at the optimum temperature of the indoor air (16-24 °C) three times higher than MAC were recorded only in 5 technological operations out of 20 – the data provided by the Centre of State Sanitary and Epidemiology Supervision of Smolensk Oblast. A significant part of mercury mechanically lost during technological processes is accumulated in the mercury sewerage system traps, wherefrom it is extracted by the forepumps and then is fed to a special tank (after chemical cleaning, distillation and filtration it is again returned to production). The enterprises manufacturing thermometers use a huge amount of water (up to 1000 m3/day), which is used in the air conditioning and ventilation systems (Enlarged Standards for Water Use ..., 1978). Usually, water contains a significant amount of dust absorbing mercury. A substantial amount of fine-dispersion metallic mercury is also discharged to the sewerage system. Solid waste from the manufacture of mercury thermometers includes primarily broken glass (contaminated glass) as well as textile waste (wool, cotton cloth). 3.5.2 Mercury consumption with thermometersThe estimation of the balance of mercury use at the instrument manufacturing enterprises, made in 1990 (the bulk use of mercury at that time was for manufacture of thermometers), showed that in technological processes about 97.38% of metal is included into the final products, 1.97% represents the so-called secondary mercury (returned to production), and 0.65% make irrecoverable loss {Report on Research Work on "Analysis ...", 1999). Since no cardinal changes have been made in the thermometers manufacturing technologies over the last 10 years, then the data provided were used to calculate the balance of modern use of mercury at the OJSC "Termopribor" (Table 3.26). Table 3.27 shows the rated (calculated) balance of mercury distribution during manufacture of thermometers. The so-called unaccounted losses, which so some reasons were not reflected in the official statistical data of the enterprise (see Table 3.25), include loss of metal discharged to the sewerage system (with suspended matter in the wastewater, as well as fine-dispersion metallic mercury not captured by the mercury sewerage system traps), unorganised emission of mercury vapours (through doors and windows), some part of which is absorbed by construction elements, equipment, cloth and footwear of personnel, etc. Table 3.26 Use of mercury at Termopribor OJSC in 1998-2002
* It was mentioned above that secondary mercury generated at Termopribor OJSC during waste disposal (recycling) is returned to production (i.e. it is included ultimately into the products); ** There are data showing that in the first half of 1990's the Klin thermometers enterprise emitted to the environment up to 100 kg of mercury (Moscow Regions Studies ..., 1996). Data on other facilities using mercury in technological processes (above all these are electrical lamp enterprises) demonstrate that up to 95% of unaccounted losses include loss of metal to the sewerage system (as fine-dispersion mercury and as part of wastewater suspended matter). This allows detailing of the balance of mercury distribution during technological processes of thermometers manufacture (Table 3.28). The fact that a substantial amount of mercury is lost with discharge to the sewerage system is confirmed by the following data. Table 3.27 Balance of mercury distribution at the OJSC "Termopribor" (total losses = 100%)
* Calculated on the basis of data provided by the enterprise (in wastewater only dissolved forms of mercury are accounted by analysis); ** Mainly these are losses of mercury to the sewerage system (absorbed on the mercury suspension, fine-dispersion metallic mercury not captured by the mercury traps), as well as unorganised emissions of mercury vapours to atmosphere, and their absorption by construction elements, equipment, clothes and footwear of personnel, etc. Table 3.28 Total balance of mercury distribution at the OJSC "Termopribor" (total losses = 100%) Discharge from Termopribor OJSC is fed through the sewerage system to the communal treatment plants where it is treated, together with communal wastewater; as a result, wastewater sludge (WWS) is generated that is stored at sludge sites. The average content of mercury in WWS in the town of Klin is very high, and in the mid 1990's it reached 220 mg/kg (Achkasov, 1987). It was established that intensity of sludge generation (dry matter) at the municipal wastewater treatment plants made 80 g/man/day (Yevilevich, Yevilevich, 1988). Population of the town of Klin is about 92,800 people (Geography of Russia ..., 1998). Thus, up to 2,800 tonnes of sludge is generated at the wastewater treatment plants of the town every year; in mid 1980's, this sludge accumulated up to 620 kg of mercury a year, basically mercury coming with wastewater from the enterprise manufacturing thermometers. At that time, the use of mercury at the Klin enterprise of thermometers made 100-130 t/year (4-5 times higher than, for example, in 2001), while losses of mercury with wastewater (if we judge their structure, as given in Table 3.28) were within 580-755 kg/year.* Ultimately, major part of this mercury was fed to the municipal treatment plants while a define amount of mercury was accumulated in the sewerage system whose length was 2 km (from the enterprise to the treatment plants). Naturally, some part of mercury was discharged with effluent to the Sestra River, which, in particular, explains its accumulation in river sediments. Thus, selective surveys show that concentration of mercury in benthic sediments of the Sestra River, downstream of the town of Klin, reach 1.55 mg/kg (Fursov, 1998). This is more than 50 times higher than the typical background level of metal in the riverbed alluvia in uncontaminated rivers (for Moscow Oblast rivers it makes, on the average, 0.03 mg/kg (Yanin, 2002)). Efficacy of treatment of wastewater, especially as regards mercury, hardly can exceed 90%; from this it follows that in mid 1990's at least 68 kg of mercury went to wastewater every year; this wastewater was discharged to the Sestra River from the municipal wastewater treatment plants. Thus, total losses of mercury at the enterprise at that time were at least 900 kg a year. There are data according to which over 1957-1993 the "Termopribor" enterprise emitted/discharged to the environment at least 35 tonnes (Fursov, 1997), i.e. 945 kg a year on the average. Survey of the distribution of mercury in different environmental components within the area of impact of Klin Termopribor enterprise, made mainly in mid 1980's, demonstrated that impacts of emissions to atmosphere were rather local. In particular, highest concentrations of metal in soils were observed directly within the industrial area of the enterprise, reaching 25 mg/kg (MAC for mercury in soils = 2.1 mg/kg) as well as in ground in the enterprise dumpsite – 20 mg/kg and in soils near the road to the dumpsite – 0.9 mg/kg. Beyond the area of the enterprise and the dumpsite area there were no concentrations of mercury in soils exceeding MAC. Maximum mercury concentrations in dust precipitated with snow also were found only nearby the enterprise (0.63 mg/kg). Vapours of mercury in atmospheric air exceeded MAC (for populated centres MAC was 0.3 μg/m3) only within the enterprise area; they were lower in the vicinity close to the enterprise area, 0.25 mg/kg, and reached background concentrations (0.025-0.010 g/m3) at a distance of 750-1000 m from the enterprise (Sokolov, 2000). B.A. Raevich found that children of employees from the Klin thermometers manufacturing enterprise had higher (usually 1.5 times higher) concentrations of mercury in urine as compared to children whose parents were employed at other enterprises. This testified to the fact that mercury was brought by parents to their living house (on clothes and footwear). Table 3.29 shows the emissions of mercury to the habitat during manufacture of thermometers at Klin Termopribor OJSC; the overwhelming majority is connected with losses of mercury to the sewerage system (mainly as fine-dispersion metallic mercury as well as wastewater suspended particles). Table 3.29 Structure of mercury emissions/discharge at OJSC "Termopribor" (total irrecoverable losses = 100%) *
* In USA, losses of mercury during production of thermometers in 1995 were 9 kg per tonne of used mercury (Locating and Estimating Air ..., 1997) 3.5.3 Use, Export and Import of Mercury ThermometersIn 2001, Klin's Termopribor OJSC manufactured more than 13.1 million medical thermometers and over 280.300 industrial (technical) thermometers. Of this number, about 20% of products were exported to foreign countries other than CIS and about the same number to CIS countries (mainly to Ukraine and Kazakhstan). The rest of the thermometers (about 7.9 million medical thermometers and 168,200 industrial thermometers, cintained not less than 17 t of mercury) were supplied to the Russian domestic market. In the recent years, mercury thermometers have been imported to Russia (from China) (mainly including methodical thermometers, TVY-120 and TAYS-006); they are manufactured by the Asmus Enterprises Ltd. (USA) which has its subsidiaries in China. By estimates of S.G. Itkin (Termopribor OJSC), import of such thermometers makes about 1 million units a year. A small number of mercury thermometers are imported also from some other countries. The total amount of Russian import of mercury thermometers in 2001 can be estimated at 1.3 million pieces (the average content of mercury per thermometer being 1 g, so up to 1.3 tonnes of mercury was imported to our country). Thus, the total number of products coming to the Russian domestic market reaches 9,368,000 thermometers, of which the overwhelming majority (over 98%) includes medical thermometers. By all evidence, practically all of them are sold to population during one year. 3.5.4 Emission of Mercury When Using ThermometersIn Russia, faulty thermometers that are not used practically always are transported to dumpsites – this is the best case. Only in the recent years efforts have been seen in some towns to organise account, collection, storage and disposal of used thermometers. First of all, special stations and tanks are organised for spent (broken) thermometers in large hospitals as well as mass-scale actions aimed at collecting thermometers from schools, children's preschool institutions, etc. It should be noted that by a special order of the Ministry of Education of Russia (of 16 June 1994) it was prohibited to use mercury and mercury-containing products in educational schools. To calculate the number of mercury thermometers used in the country every year, we will give some limited estimates that are available. By estimates of V.V. Bogatov (presentation at the conference "Mercury. Comprehensive Security System, 21-23 may 1996) in mid 1990's, in St. Petersburg, up to 500,000 mercury thermometers were put out of use (faulty, broken, etc.) (i.e. about one thermometer per 10 citizens). By the data provided by the agency "Rtutservice" and NPP "Ecotrom", at the end of 1990's in Moscow, 0.05-0.8 million mercury thermometers were put out of use every year, i.e. about 650,000 (1 thermometer per 13 citizens), of which not more than 1% was collected and disposed. In the republic of Mordovia (920,000 population), in 2000-2002, up to 40,000 mercury thermometers were supplied to the trade system every year (1 thermometer per 23 persons); by all evidence, about the same number of thermometers were put out of use. Thus, depending on the region, every year one thermometer per 10-23 citizens of the country is put out of use. It is obvious that the data for Mordovia, where the share of urban population does not exceed 60%, do not adequately reflect the real situation of the country (the share of urban population in Russia exceeds 73%). For calculation, it is probably necessary to use the average specific indicator: 1 thermometer per 165 persons. For the whole country it will make just over 9 million thermometers, which is a little smaller than the number of thermometers supplied to the domestic market in 2001 (which is however quite natural). These 9 million thermometers contain at least 18.1 tonnes of mercury; almost the entire amount (up to 90-85%) is brought – at best – to the sewerage discharge, garbage or dumpsites. 3.6 Barometers, Manometers and Other Measuring Equipment3.6.1 Production of Mercury-containing Measuring EquipmentMercury has been used for a long time for manufacture of mercury switches, mercury valves, pressure gauges, barometers, mercury pumps and other devices. At present, mass-scale manufacture of most of such devices has been terminated for various reasons. Nevertheless, some devices manufacture din the previous years are still used in different spheres, both housing and industrial. There are data that mercury is present in mobile phones as well as in computers (up to 0.0022% of the total weight): it is used in electronic keys and flat monitors (http://www.physfac.bspu.secta.ru/mirror/izone/izon...). By estimates of Promotkhody MGUP (Industrial waste), only in Moscow more than 6,000 tonnes of radio-electronic, electrical engineering and medical products (devices) are used, containing mercury and mercury compounds (Demina, 19999). Enterprises of the city of Omsk have more than 16,000 different devices containing over 250 kg of mercury (http://www.rmx.ru/news/&news=295). By estimates, mercury-containing devices (pressure gauges, ignitrons, etc.) used by the enterprises and organizations in Krasnodar Krai include about 20 tonnes of metallic mercury (Sheveleva, 2000). If we take the entire country, the amount of mercury in different devices that are used by enterprises and organisations nowadays can reach several thousand tonnes. Manometer devices (pressure gauges) are used to measure pressure of liquids and gases. Barometers are used to measure atmospheric pressure, vacuum meters are used to measure pressure near zero, and sphygmomanometers are used to measure arterial pressure (Riva Rocci devices). In the former USSR, the main manufacturers of mercury barometers and pressure gauges were: Klin Thermometer Plant (Termopribor OJSC), Teplocontrol enterprise (city of Kazan), Aktryubrentgen enterprise (Kazakhstan), Telshai Plant of Computing Machines (Lithuania), and Lubenskiy Plant of Computing Machines (Ukraine). Currently, Russian has stopped manufacture of mercury pressure gauges (barometers, vacuum meters, sphygmomanometers); it was terminated some years ago. 3.6.2 Mercury Consumption with Measuring EquipmentDepending on the form of communicating vessels, mercury barometers can be plate-type, siphon or siphon-plate barometers. Action of mercury barometers is based on equalising atmospheric pressure by the mercury column pressure in the barometric (made from thermometer glass) tube (Table 3.30). Table 3.30 Content of mercury in barometers (Report on Scientific Research devoted to the Topic "Study ..., 2000).
Mercury barometers are highly precise devices; they are used practically in all meteorological stations and services of aerodromes; they are also used to check operation of other types of barometers. They are used in scientific and production laboratories. When handled carefully, mercury barometers can operate several dozens years (to be filled from time to time with mercury). Only in the recent years, meteorological stations have started using mercury-free network barometer ÁÐÑ-1M that can be interfaced with PC. The total number of mercury barometers used nowadays cannot be counted precisely, however it can be assumed that their number can be several thousands (more than 600 meteorological stations operate in Russia; about 400 civil aerodromes, etc.). With the average content of mercury per barometer being up to 1 kg, the total weight in such devices can make several tonnes (5-6 tonnes). Every year some amount of mercury is used to supplement barometers. Sphygmomanometers contain up to 10% of mercury on the average (of the total weight). They are still used in medical practices since they are reliable and highly precise. A definite number of sphygmomanometers were imported, some years ago, to USSR and Russia through the so-called humanitarian aid. In 2001, there were 10,600 hospital institutions in Russia, while the number of medical and outpatient polyclinics was 21,300 (Industry of Russia..., 2002). If we assume that every such institution has at least one mercury sphygmomanometer, then their total number will be more than 30,000 pieces (with at least 300 kg of mercury). In mercury pressure gauges ÌÁÏ (mercury pressure gauges, checking bureau) and Ì×Ð-3 (mercury, plate-type pressure gauge) the content of mercury is 211 and 1,683 g, respectively (Report on Scientific Research devoted to the Topic "Study ..., 2000). In the past, mercury float-type differential pressure gauges were very widely spread (types ÄÏ-710Ðá ÄÒ-5á ÄÒ-50), however their industrial manufacture was terminated several years ago. Nevertheless, some of these devices are still used in boiler houses, gas distribution stations, laboratories, etc. It should be noted that one can find ads in Internet about sale of differential mercury pressure gauges ÄÒT-50 (probably, from store stocks), which indicates to some demand for these items on the Russian market, although it is not the device itself can be offered for sale, but rather mercury in it. 3.6.3 Mercury in Waste Products and Releases of to Air, Soil and WaterBy the data of the Exotrom NPP (Moscow), different enterprises and organizations of the city have supplied to this organization, in the recent years, several; dozens of differential mercury pressure gauges containing mercury a year (for example, 50 items in 2002). If take the entire Russia, the number of mercury pressure gauges to be disposed (based on the data from section 3.6.1) may, probably, constitute several hundreds (up to a thousand) a year (containing 300-500 kg of mercury). 3.7 Electrochemical Cells3.7.1 Production of Mercury-containing Electrochemical CellsElectrochemical cells are separate cells of current sources that generate electricity as a result of direct transformation of chemical energy of redox reactions; they are used for a single electrical discharge (also called primary galvanic cells). Groups of identical electrochemical cells can be connected electrically and structurally into an electric battery so as to receive such electrical current (quantity of electricity) that cannot be generated by a single cell. Basic components of an electrochemical cell are two electrodes of different nature and electrolyte. Usually, electrodes are metal plates of meshes coated with reagents (active substance): a reducing agent (zinc, lithium, etc.) is deposited on the negative electrode, while oxidizing agent (oxides of manganese, mercury or other metals) is deposited on the positive electrode. Electrochemical cells and batteries are used mainly for electrical supply to portable equipment and, therefore, are manufactured mostly with thickened or solid electrolyte. In the former USSR, in 1980's, up to 100-130 tonnes of mercury were used every year for manufacture of electrochemical cells and batteries (mercury-zinc, alkali and salt – manganese-zinc and silver-zinc). The main manufacturers of these products were Yelets Cell Plant (now OJSC "Energia", town of Yelets, Lipetsk Oblast), NPO "Kvant" (Moscow City), "Elastik" enterprise (town of Lesnoy, Shilovskiy District, Ryazan Oblast), "Signal" enterprise (town of Chelyabinsk), "Sirius" enterprise (town of Klaipeda, Lithuania), "Uralelement" enterprise (town of Verkhny Ufaley, Chelyabinsk Oblast), "Kuzbaselement" enterprise (town of Novokuznetsk), "Vostsibelement" plant (town of Cheremkhovo, Irkutsk Oblast), "Programmator" enterprise (town of Vyazma, Smolensk Oblast), and the Condenser Plant (town of Novosibirsk). Also, normal primary cells (mercury-cadmium and mercury-zinc) were manufactured in small numbers for industrial and scientific use. The total manufacture of electrochemical cells in the USSR at the end of 1980's was up to 1 billion cells a year. For example, in 1990 alone 683 million electrochemical cells were manufactured for home electrical equipment; of them, over 333 million cells were manufactured at the Yelets Cell Plant. Since early 1990's, there has been a sharp reduction of their manufacture in Russia (Table 3.31). Many enterprises discontinued their output all together; others halved their output; today, some enterprise manufacture electrochemical cells and batteries only by orders from enterprises and organizations. All this resulted in a substantial decrease of the use of mercury (Table 3.32): in 2001 about 0.8 tonnes of mercury was used for this purpose. The main manufacturers of electrochemical cells for home electrical appliances have been FGUP "Uralelement", town of Verkhny Ufaley (manganese-zinc alkali cells and batteries) and OJSC "Energia", town of Yelets (mercury-zinc and alkali manganese-zinc cells and batteries). Table 3.31 Manufacture of all types of electrochemical cells for home electrical appliances in the USSR and in Russia, in million pieces (Russian Statistical Yearbook ..., 2002; Lipetsk Oblast in Figures for 2001 ..., 2002; Main Economic and Social Indicators of the Lipetsk Oblast ..., 2002; with amendments from the author)
* Uralelement enterprise manufactured 2.8 million pieces; ** In 1998, Energia OJSC developed a programme for transition to manufacture of cells for air-zinc and lithium systems replacing mercury-zinc systems. Mercury in Produced Batteries In mercury-zinc cells (according to the domestic nomenclature, these are cells of the type ÐÖ: 10ÐÖ53, 5ÐÖ83, 10ÐÖ85, etc.), manufactured as sealed low-capacity devices with a disk (button or tablet) or cylindrical structure, the active mass of the positive electrode includes mercury oxide HgO (also called red or yellow mercury oxide) with a fine-refined graphite added (5-15%); the negative electrode includes powder zinc with a small amount of mercury (amalgamated zinc). Table 3.32 Use of mercury at Energia OJSC, town of Yelets (Report on Research ..., 1999; Lipetsk Oblast in Figures for 2001 ..., 2002; Main Economic and Social Indicators of the Lipetsk Oblast ..., 2002)
* Estimates. The active mass of the positive electrode is pressed into the cell body while the negative mass is pressed into its cover. Before the electrochemical cell is assembled, a gasket from porous paper is placed between the body and the cover; this gasket is impregnated with electrolyte composed of a KOH (potassium hydroxide) solution with zinc oxide. An insulating rubber gasket is placed between the body and the cover, which plays the role of the seal. Cells of the ÐÖ type contain on the average up to 1% of metallic mercury and up to 37% of mercury oxide of their total weight (Report on Research of Topic "Study of Nomenclature ..., 2000). The weight of these elements varies from a few grams (button structure) to 45-370 g (cylindrical structure); the weight of the battery "Priboy-2C" is 450 g. Self-discharge of the cells of a mercury-zinc system during their storage is negligible: it is decreased by not more than 10% during a period from 12 months and till the end of their service life; alongside with high impact resistance, vibration stability and resistance to significant vacuum and high pressure this property defined their use in military equipment, field devices, radiosondes, medical devices, watches and clocks, etc. In alkali manganese-zinc elements of cylindrical structure (types RL-316, RL-332, RL-343), the positive electrode is manganese oxide with graphite, acetylene ash and electrolyte (the latter includes potassium hydroxide, zinc oxide, potassium biochromate, and carbonates). The negative electrode is made from a homogeneous paste mixture: powder zinc – 1000 g, mercury oxide – 15 g, potato starch – 45 g, and electrolyte – 340 ml (Report on Research of Topic "Study of Nomenclature ..., 2000). Thus, the negative electrode includes up to 1.1% of mercury oxide (or 1.5% of the zinc weight). In particular, an RL-332 cell (its weight is 35 g) contains 66 mg of mercury oxide; an RL-343 cell (its weight is 70 g) contains 154 mg of mercury oxide; and button-structure cells contain not more than 20-25 mg of mercury. Korund battery contains 0.5% (of its eight) of mercury oxide; some batteries of the series "Baken" (their weight is up to 2.5 kg) contain 18-25 g of mercury oxide. Mercury in Waste Products and Releases of to Air, Soil and Water In the common case, the technological scheme for manufacture of electrochemical cells includes three main groups of operations: preparation of the anode mass; making of the cathode; and assembly of cells. Preparation of the anode mass includes treatment (filtration) of mercury, weighing of mercury, filling of mercury into the mixer, mixing of component materials, loading out of the anode mass, packing of feeders, and cleaning of the mixer parts. When the cathode is made, HgO, MnO2 and graphite are fed from the hopper to the mixer and the resultant mixture is fed for additional treatment where it is compacted. Then the ready cathode and anode are fed to the shop for assembly of electrochemical cells. Cells are assembled on automatic (semi-automatic) lines, which perform dose dispensing of the anode mass, fill the cell body with the anode mass, seal the cell, etc. When electrochemical cells are produced, mercury is emitted to the air (as vapours or mercury oxide dust), during preparation of the anode mass and making of the cathode, assembly of cells, and during maintenance and repair of equipment; mechanical losses of metallic mercury occur during its filtration, weighing and preparation of amalgam. Usually, all working rooms have general exchange plenum and exhaust ventilation system as well as dust entraining systems; mercury filtration and weighing is made inside exhaust cabinets; the other technological operations, including those performed on automatic assembly lines, as a rule, are made using equipment that has no local exhaust equipment. Production wastewater is fed to the enterprise local wastewater treatment plants (for example, at Energia OJSC a reagent treatment method is used); then wastewater is fed, through the sewerage system, to communal treatment facilities and, after them, it is discharged to water bodies. Data related to the period of active operation of the Yelets enterprise indicate to a high emission of mercury vapours to air of the working rooms at all stages of preparation of electrochemical cells (Pyatnitsky, 1994). For example, concentration of mercury vapours and of mercury oxide in the mercury-zinc cells shop 25 times exceeded the maximum allowed concentration (MAC); high concentrations of mercury were also found in wastewater after washing of hands and special clothes, walls and floors. Concentration of mercury vapours in the air of the manganese-zinc cells assembly shop was much smaller, however, on the average it was 2 times higher than MAC. The highest concentrations of mercury vapours in the air were observed during filling of metal to the mixer (Table 3.33); very often they exceeded MACmax (maximum allowed single MAC in the air of the working area) (Karelin et al., 1992). Technological operations performed during filling of electrochemical cells with anode mass and during their assembly emit less mercury vapours to the air. As a rule, the most dangerous operation is maintenance and repair of assembly lines (Table 3.34). High concentration of mercury vapours were practically recorded in all production rooms at the Yelets Cell Plant (Pyatnitsky, 1994). Cases of chronic mercury intoxication were recorded among the enterprise workers; these cases were dominant as compared to other occupational diseases. High concentration of mercury vapours are also found in the soil in the enterprise area and in its surrounding, as well as in other areas of Yelets (Environmental Condition of the Lipetsk Oblast in 1998..., 1999). Table 3.33 Mercury in the air of the room wherein anode mass is prepared (Karelin et al., 1992).
Table 3.34 Mercury in the air of the cell assembly shop (Karelin et al., 1992)
A sharp decrease of output of electrochemical cells at Russian enterprises and, hence, respective decrease of mercury use at these enterprises has resulted in a sharp decrease of mercury emission to atmosphere. Thus, while in 1992 in Yelets 107 kg of mercury was emitted to atmosphere, then in 1998 it made 9 kg (Environmental Condition of the Lipetsk Oblast in 1998..., 1999). Balance of mercury distribution during manufacture of electrochemical cells Assessment of the balance of mercury distribution during manufacture of electrochemical cells, made for industrial enterprises of the USSR in 1990-, showed that 72.4% of the total weight of used metal was included into the final products while 27.6% was lost (with rejected products and other solid waste, discharged with wastewater or emitted to atmosphere) (Report on Research ..., 1999). Data (for early 1990's) for different enterprises in cities of Novosibirsk and Novokuznetsk, which at that time manufactured electrochemical cells and battaries, show that these enterprises, taken together, released to the environment 770 kg of mercury a year; of this amount, 40 kg were emitted to atmosphere and 60 kg were discharged to water bodies, and the remaining amount – 670 kg – was concentrated in solid waste (Mercury in Environment of Siberia: Estimates of the Input from Natural and Anthropogenic Sources ..., 1995). Thus, the structure of mercury losses during manufacture of electrochemical cells is as follows: 5.2% is emissions of metal to atmosphere, 7.8% is lost to the sewerage system, and 87% is lost with solid waste. Since in the recent decade no radical changes have been seen in the technologies applied for manufacture of electrochemical cells at Russian enterprises, then these indicators can be quite safely used to calculate the balance of mercury distribution and mercury emission to the environment (Table 3.35). Table 3.35 Balance of mercury distribution during manufacture of electrochemical cells in Russia, 2001
* About 60% include mercury from the OJSC "Energia", Yelets. ** Including mercury oxide as metallic mercury; *** High losses of mercury were explained, in many respects, by a large-scale manufacture of cells at the enterprises; it cannot be ruled out that today technological losses might be smaller (however, this can hardly change the total picture significantly); **** Some mercury is emitted to atmosphere with dust as HgO; ***** Most probably, a greater part includes fine-dispersion metallic mercury; ****** Technological rejection rate has always been very high at many Russian enterprises (up to 10% or more of the total output of electrochemical cells); rejected cells made the bulk of solid waste generated at these enterprises; by estimates of M.N. Borzykh (personal communication) Russian enterprises which manufactured manganese-zinc cells have accumulated 3-7,000 tonnes of solid waste each, containing up to 3-7 tonnes of mercury; in particular, in the vicinity of the "Elastik" enterprise (in Ryazan Oblast) more than 7,000 tonnes of rejected manganese-zinc cells are stored in the open site, with the content of mercury in one cell up to 1.0% (Matsevich et al., 1994). 3.7.2 Export and Import of Electrochemical CellsIn the recent years, the Russian domestic market of electrochemical cells and batteries has been totally formed by import; the volumes of import has been permanently increasing and now make at least 11,000 tonnes (this unit is used by the customs statistics to account trade in electrochemical cells (Customs Statistics ..., 2000; Customs Statistics ..., 2001)). The main importers of electrochemical cells to Russia are Poland, China and Korea (up to 65% of the total import), as well as Japan, Belgium, Taiwan, Germany and some other countries. Russian export of electrochemical cells is small, making, for example, 24 tonnes in 19999 ands 65 tonnes in 2000 (mainly to Ukraine and Kazakhstan). It is known that at present the greatest amount of electrochemical cells in the world includes primary zinc-carbon and especially alkali manganese-zinc cells and batteries. For example, more than 10 billion alkali cells are sold every year, while their share in the markets of USA and Canada is 80%, and in Japan it is 65% (The World Market of Electrical ..., 2001). According to instruction of then European Union, since 1 January 2000 it is prohibited to manufacture and use all cells and batteries containing more than 0.0005% (weight percent) of mercury as well as alkali manganese cells with the content of mercury over 0.025% (by weight) (Batterien mit zu ..., 2001). Similar restrictions on the content of mercury in primary electrochemical cells exist in USA, Japan and other countries. A selective analysis of electrochemical cells offered in the shops of Moscow, Saransk, Smolensk and Penza and in some small towns of Moscow and Penza Oblasts and in the Republic of Mordovia demonstrates that only a few of such products on sale have an indication that they include mercury (for example, cylindrical batteries of the company Konnoc Battery Industrial Co., Ltd., containing 0.009% of mercury); many of such cells have indication that that they do not include mercury. The battery team site has a catalogue of electrochemical cells and batteries offered for sale, which includes a list of 438 types of products (manufactured by the leading foreign firms), of which 35% include alkali cells, about 209% are lithium cells, 24% are silver oxide cells, 18% are zinc-carbon and only 4 types are named as mercury cells (Energizer firm). It is indicative that the volumes of cells offered for sale, for example volumes of alkali cells of cylindrical structure vary from 1,000 to 100,000 cells, while volumes of mercury cells include only up to 10 cells, which, undoubtedly, testifies to the fact that their import to Russia is very small. To estimate the weight of mercury imported to Russia with electrochemical cells and batteries, we will assume (with a definite degree of convention) that out of 11,000 tonnes of imported products about 30% include alkali cells and batteries with the content of mercury in them not more than 0.025% (by weight), calculated on the ground of general requirements. Simple calculations show that such amount of cells imported to the country include about 0.8 tonnes of mercury, while if we take into account (possible) supply of mercury and other mercury-containing cells, this amount may be about 1 tonne of metal. 3.7.3 Use and Disposal of Electrochemical CellsIn the former USSR and now in Russia, primary electrochemical cells and batteries have never been specially collected on a mass scale and, hence, never disposed; at best, they are taken to waste dumpsites (Matsevich et al., 1994; Yanin, 1998). By data of Ecotrom NPP, in Moscow, at the end of 1990's, different enterprises and organizations used up to 1 million electrochemical cells and batteries every year (the total weight about 100 tonnes); over 15 million electrochemical cells and batteries (about 1,500 tonnes) were used by population. Of this amount, not more than 1% were collected (at enterprises) and then sent to processing (at Kubantsvetmet CJSC). In the recent 2-3 years, in Moscow, only one organization has sent used mercury batteries to Ecotrom SPE for disposal (about 15,000 batteries a year). There are data showing that "Green Peace" of Russia has organised, in IKEA shops, points for collection of electrochemical cells and batteries from population (http://eyge.narod.ru/Russian/List/08-10-200246.ht...), although nothing is mentioned about their work. It is known that the most widely spread alkali cells usually have 1-year service life; after that 60% of them are discarded. Only 20% can be used for 2 years; and only 10% can be used for 3 years (Matsui Yasuhiro, 1994). We can state that now the overwhelming majority of electrochemical cells and batteries manufactured in Russia and imported to this country are discarded during one year. Also, very frequently we can find on sale batteries of substandard quality (probably, fakes), which significantly expedites the rates of their rejection with waste. The total amount of mercury which is finally sent to dumpsites (both organized and unorganised) with used electrochemical cells and batteries, with due account of the above information, makes about 1.6 tonnes (Fihure 3.9). Figure 3.9 Distribution of mercury during manufacture and use of electrochemical cells and batteries in Russia in 2001
Still now, a very serious problem is solid waste (mainly as rejected cells), stored near the Russian manufacturers of electrochemical cells and batteries. It should be noted that in the former USSR, technological processes and required equipment were developed for thermal treatment of mercury-containing manganese-zinc cells (Borzykh, 1989; Borzykh et al, 1988; Levitskaya et al., 1987; Levitskaya et al., 1988; Matsevich et al, 1994). The plant that was designed and tested can also be used to recycle other small products (for example, ammunitions containing detonating mercury). The federal programme "Waste" approved by resolution No. 1098 of the RF Government on 13 September 1996 planned to create in the Ryazan Oblast (at Elastik enterprise), using the indicated plant, respective facilities (with the output of 500 tonnes of waster a year) for treatment (recycling) of mercury-containing electrochemical cells. Unfortunately, this decision has never been fulfilled. 3.8 Light SourcesMercury is a component of gas-discharge lamps in which glow is crated from electrical discharge in metal vapours or in a mixture of gas and vapour. There are three types of mercury lamps:
Tubes of mercury lamps can be coated with a layer of luminophor or without such coating. 3.8.1 Production of Mercury-containing Light SourcesIn 2000-2002, Russian enterprises manufactured the following groups of mercury lamps (Table 3.36). Mass-production low-pressure lamps included tubular luminescent lamps; high-pressure and ultrahigh pressure lamps included lamps ÄÐË, ÄÍàÒ and ÄíàÇ (Russian designation letters). The annual production output of low-pressure lamps made 69-71 million lamps, and the annual output of high-pressure and ultrahigh pressure lamps made 6.5-7 million lamps. Compact luminescent lamps (up to 500-600,000 lamps/year) were manufactured by Lisma-VNIIIS OJSC (150,000 lamps/year) and Moscow Electrical Lamp Plant (MELZ OJSC). (Problems of modern ..., 2002). Table 3.36 Basic groups of mercury lamps manufactured in Russia (Database ...., 2001; Sources of Light..., 2003; Reference Book on ..., 1995)).
* In frequent switching conditions, the service life of the lamp notably reduces. In 2001, the main manufacturers of mercury lamps and, hence, the main users of mercury were: Lisma OJSC (Saransk) and Svet OJSC (Smolensk). Smolensk Electrical Lamp Plant (Svet OJSC) specialises in manufacture of low-pressure luminescent lamps – the annual output is up to 50% of domestic lamps of similar kinds (over 35.6 million lamps in 2001). Saransk Lisma OJSC has a very diverse nomenclature of products (over 700 names of various-purpose light sources, lighting fixtures, luminaires, etc.). Luminescent low-pressure lamps are basically manufactured by Saransk Electrical Lamp Plant "Lisma-SELZ" (35 million lamps in 2001). High-pressure and ultrahigh pressure lamps (about 5.8 million pieces in 2001) were manufactured at the Saransk Plant of Special Light Sources and Electro-Vacuum Glass (Lisma-SIS-EVS). Other domestic manufacturers (5-6 enterprises) of mercury lamps (basically high-pressure and special lamps), indicated in the Database "Participants of the Light Equipment Market", prepared by the Moscow House of Light (Database ... 2001), had, in 2001, insignificant production capacities (up to 100-150,000 lamps a year). Some of them manufactured high-pressure mercury lamps using ready discharge tubes supplied from abroad. On the whole, their operation had a very small impact on the Russian mercury lamps market and, hence, on the use of mercury by electrical lamp manufacturers (Table 3.37). Table 3.37 Use of mercury by Russian electrical lamp manufacturers in 2001
* Up to 90% of mercury is used by the Saransk Electrical Lamp Plant (Lisma-SELZ); ** Up to 87% of mercury is used for production of low-pressure luminescent lamps In the recent years, manufacture of neon tubes for light advertising has been developed in Russia (in English-speaking countries it is called "bending" by the name of the main operation, which is bending of glass tubes). For example, in Moscow alone there were over 20 neon lamp manufactures in 2001. As a rule, these are small enterprises whose entire equipment is located within 20 square metres, with 4-6 personnel members, and the use of metallic mercury not more than 8-10 kg/year. 3.8.1.1 Technological Processes Domestic electrical lamp plants are mainly equipped with outdated semi-automated lines for assembly of luminescent lamps, manufactured in Hungary long time ago (by the Tungsram company), with some domestic machines (the rated output of one line is 1,200 lamps/hour). The basis of some assembly lines is made by English machines manufactured by Badalex. In 2001, ten lines were in operation at the Smolensk Electrical Lamp Plant, and 12 assembly lines at the Saransk Electrical Lamp Plant. The process of lamp assembly begins with washing and drying of glass tubes (lamp tubes), deposition and drying of the luminophor layer (Figure 3.10). The glass lamps manufactured by the glass-making facility, are transported by a conveyor to the lamp assembly shop wherein they are fed to special machines with nozzles for tube washing and drying as well as with tanks with luminophor suspension. In the recent years, luminophor suspension has been made by using a water-soluble polymer (based on methyl acrylate) that assures fixing of the luminophor layer to the walls of the tubes in the process of deposition. Then, this binder is removed (burned out). Glass tubes are fed to the tank and are placed on it, following which the luminophor suspension is sucked into them by the vacuum built in the tubes. Photo elements installed at the top end of the tube send a signal to switch off vacuum when suspension reaches up to the point where they are placed. Afterwards, the residual suspension flows back into the tank, and the tubes are moved to the position for drying of the luminophor layer. Warm air (at 50-60 C) for drying of washes tubes is fed from the binder burnout stoves and for drying of the luminophor from air heaters. The, the tubes with the deposited and dried luminophor are fed to the binder burnout machines made of four parts: a conveyor for loading and marking of tubes; a burnout stove; a conveyor for feeding of tubes to the soldering machine with a matted screen at the end of the conveyor (where binder burnout quality is checked); and mechanisms for cleaning of the luminophor layer at the ends of the tubes. The following operation includes welding of the tubes, preceded by installation of legs and oxidation. To this end, glass pans, exhaust tubes and metal three-link legs are fed to a special machine. The legs and exhaust tubes are pressed as a single unit with the pan, thereby forming the so-called glass leg which is moved to the kiln wherein it gradually cools down. The exhaust tube is a glass capillary 5 mm in diameter, which is used to connect the internal space of the lamp with the suction system; it is also used to introduce mercury and inert gas into the lamp. The exhaust tube has a hole only on the leg for one end of the lamp (the leg with a purged exhaust tube); the second leg does not have it (the leg with the exhaust tube that was not purged). The automated installation and oxidation machine is used to fix three-spiral cathodes into the hooks of the nickel sections of the legs and to deposit a layer of oxide suspension that is then dried while the legs are fed automatically to the tube welding machines (using gas burners). Figure 3.10 Technological process: assembly of luminescent lamps
The main operation in the process of manufacture of luminescent lamps is their pumping at the semi-automated pumping machines: air is pumped from the lamp, the tubes are heated to remove contamination from the glass and the luminophor layer; heat treatment of the electrodes is made by current (binder degradation products as well as oxide coating carbonates are pumped off); mercury and inert gas is introduced into the lamp; electrodes are activated; lamps are unsoldered and placed onto the conveyor leading to the basing machine. Air is pumped from the lamps by means of vacuum pumps. Metallic mercury used in the technological process is cleaned (distilled); then it is fed to the dispensing heads of the automated dispensing machines used to feed metal to the lamp (as a drop with the defined weight). Lamps with pumped air are fed by the conveyor to the basing machine. The exhaust tube that has not been purged is broken off automatically on the conveyor; the workers (making basing operations), located in the middle of the conveyor, put (manually) bases with the mastic onto the lamps. After thermal treatment the basing mastic strongly binds the base with the glass tube. Then lamps are fed by the conveyor to the training and testing machines, after which the products that meet technical specifications are packed and fed to the warehouse for interim storage, while rejected products are sent for disposal. The luminescent lamps assembly shop is equipped with general exchange ventilation, while the workplaces at the pumping semi-automatic machines are equipped with plenum and exhaust ventilation. The shop includes a team for de-mercuration operations, who make periodical treatment (usually twice a shift) of the equipment and the floor, and collect broken exhaust tubes, glass tubes and lamps. At the Smolensk Electrical Lamp Plant de-mercuration of the shop is made using 3% solution of sodium hypochlorite; at the Saransk Electrical Lamp Plant a water solution of potassium permanganate oxidised with hydrochloric acid is used. After treatment, the de-mercuration solution is washed off by a jet of water towards the chutes of the so-called mercury sewerage system equipped with traps for collecting metallic mercury (most of this mercury is the result of mechanical loss of metal during lamp assembly). Mercury is removed from the traps by fore-vacuum pumps; then, it is sent for cleaning or recycling (reprocessing). The technological process for production of mercury lamps, considered above, includes a great share of manual operations and is characterised by significant losses of mercury, especially on the assembly lines, and by different unfavourable production factors (high concentrations of mercury vapours and some organic compounds, high air temperature, noise, infrared and electromagnetic radiation). The basis of the majority lamp assembly lines, operated at the domestic enterprises, is made by equipment with practically 100% wear, which results in high rejection rates, above all, because of braking of tubes and cracking of glass at the soldering joints (Bolokhontseva et al., 2002; Stepanov, 1997). In particular, while the share of the so-called breakage of lamp tubes, as stipulated by the design, must not exceed 8%, then in reality it reaches 20-25%. The number of rejected lamps (that did not pass technical inspection) is rather high (up to 7-9% of the total output). Manufacture of high-pressure mercury lamps is organised on the assembly lines that are, in many aspects, similar to those considered above, however, they are, as a rule, characterised by better quality of equipment (or, at least, less worn out equipment). Specific Content of Mercury in Lamps Domestic reference books and catalogues on lighting equipment include data showing that amounts of mercury in every low-pressure luminescent lamp manufactured by Russian enterprises makes from 20 to 50 mg (see, for example (Light Sources. Catalogue of Lighting Equipment, 2003; Petrov, 19999; Rokhlin, 1991). However it is known that the technologies used by Russian enterprises to manufacture luminescent lamps was based, initially, on introducing into each product from 80 to 120 mg of metallic mercury (without account of possible losses). This was the amount of metal put into the ampoule part of the dispenser head of the automatic dispensing machine; ultimately, at least 50-80 mg of mercury was put into each product. In the recent years, Svet OJSC (Smolensk) has organised technical actions for improving the dispensing heads, which allowed reducing the average dose of mercury put into each luminescent lamp (without account of mercury losses): in 1998-2000 to 72.8-74.3 mg, in 2001 to 67.7 mg, in 2002 to 63.4 mg, and in 2003 to 52.6 mg. Of ten luminescent lamp assembly lines in operation at the Smolensk Plant, two assembly lines have a smaller specific use of mercury put into the lamp (50 mg); two lines use titanium mercuride (getter-mercury dose dispensers), however they are not effective lines, having low output capacity. In 2001, at the Saransk Electrical Lamp Plant, at least 100 mg of mercury were put into the ampoule part of the automatic dispensing machines – of this amount, 60-70% were put into the lamp (66 mg on the average). Attempts to use in the production getter-mercury dispensing machines in two production lines were not successful. Table 3.38 shows data characterising the levels of concentration of mercury in the main types of lamps, manufactured by Russian enterprises. Table 3.38 Concentration of mercury in main types of domestically produced discharge lamps, 2001
* According to (Risk to health and the ..., 2002), one neon tube contains 10 mg of mercury; there are data showing that at Russian workshop enterprises mercury is put into neon tubes manually, which a priori assumes a significantly higher amount. Sources of Mercury Emission and its Content in the Work Area Air Main losses of metallic mercury and intensive emission of its vapours into the air of the working rooms takes place at the pumping semi-automatic machine where metal is put into the lamp. The device used to put mercury into the glass tube (the dispensing head) must provide simultaneously for the vacuum compaction and the correct dosing of metal. Ideally, a drop of mercury, under its weight, must get into the lamp through the capillary of the exhaust tube, strictly vertically. In practice this does not happen always, and the mercury, colliding on the walls of the capillary, remains partially in the exhaust tube and is partially lost. After the soldering the heated exhaust tube with residual mercury as well as mechanically lost mercury are fed to the de-mercuration solution, spilt on the floor of the pumping room. From the time of soldering and until the time the exhaust tube is put into the solution, this tube represents a source of intensive emission of mercury vapours into the air. Mercury vapours are emitted to the production area during air pumping from the lamp, especially when the lamp, for some reason, is fed for a new cycle of pumping of air and filling of mercury, as well as during soldering of lamps when the vacuum pumps are switched off. Glass tubes are often cracked or broken on the assembly lines, which results in the loss of mercury and emission of its vapours into the air. Mechanical losses of metal and emission of its vapours into the air also take place in the process of cleaning (distillation) of mercury, during filling of automatic dispensing machines and maintenance of dispensing heads, during collection of soldered or broken exhaust tubes and broken lamps, as well as during maintenance of vacuum pumps and disposal of rejected lamps. High air temperature in the working rooms reaching in the warm seasons of the year 40 °C (18°C is the standard temperature) during lamp assembly facilitates intensive degassing of mercury (Bolokhontseva et al., 2002). As a rule, the amount of mercury lost at Russian enterprises during assembly of luminescent lamps (especially during pumping of air) makes from 30 to 40% of the total weight of the metal used. The air in the lamp assembly shop includes high concentrations of mercury vapours. For example, of 856 measurements made during 2001 on the lamp assembly lines of the Smolensk Electrical Lamp Plant, in 85% of cases the average concentration of mercury vapours exceeded 8 times the maximum single allowed concentration (MACmax) (this value varied from 4 to 15 MACmax) (Bolokhontseva et al., 2002). The highest concentrations of mercury vapours were recorded near the automatic pumping machines. During the subsequent operations (basing, training, testing and packing of lamps), where there is no contact with metallic mercury, the concentration of its vapours in the air was smaller, however it was within 2 to 5 MACmax. As a rule, other rooms of the electrical lamp plants also have, stably, high concentration of mercury vapours (Table 3.39 and Table 3.40, Figure 3.11). The luminescent lamp assembly shop is characterised by presence of secondary sources for mercury emission into the air (construction structures and technological equipment that deposit metal with time, to different extent); such sources in high-temperature conditions, characteristic of such enterprises, constantly emit mercury to the environment. Table 3.39 Concentration of the mercury vapours in the room air at Smolensk Electrical Lamp Plant *
* Hereinafter, the primary actual data for the Smolensk Plant, used as a base for calculations and assessments, were provided by the Centres of State Sanitary and Epidemiological Surveillance of the Smolensk Oblast and the City of Smolensk. Table 3.40 Dynamic of changes of the mercury vapour concentrations in the air at the semi-automatic pumping machine, Smolensk Electrical Lamp Plant *
* In the area of breathing of workers (1-2 m high above the floor). Intensity of pollution of the enterprise rooms with mercury is illustrated by data on the frequency of occupational diseases of the workers (chronic mercury intoxication) (Figure 3.12). Thus, at the Saransk Electrical Lamp Plant the diagnosis "occupational mercury intoxication" was made for 287 workers (86 workers in 1996-2001); among them 90% are women. Basic professions are mostly susceptible to mercury intoxication: pumping workers (31%), soldering workers (15%), basing workers (14%). At the Smolensk Electrical Lamp Plant, 67 cases of chronic mercury intoxication were recorded during 1970-2001 (5 cases were recorded in 1997-2001) (Bolokhontseva et al., 2002). Annually, up to 30-90 cases of mercury affect are recorded, i.e. workers with a high concentration of mercury in urine, 1-2 orders above the background (normal) level. Figure 3.11 Distribution of average annual concentration of the mercury vapours in the air of the pumping room of the luminescent lamp assembly shop at the Saransk Electrical Lamp Plant. (In 1988-1989, de-mercuration actions were organised here and many secondary sources of mercury were eliminated; routine de-mercuration of rooms became regular). (Stepanov, 1997; with amendments)
Figure 3.12 Dynamic of development of chronic mercury intoxication among workers, at the Saransk Electrical Lamp Plant (Stepanov, 1997, with amendments)
Distribution of Mercury by Manufacture of Luminescent Lamps Table 3.41 shows data characterising manufacture of luminescent lamps, use of mercury and generation of waste at Smolensk Electrical Lamp Plant (Svet OJSC, Smolensk City) in 1998-2002 and for the first three months of 2003. They were used as the basis for calculations of the balance of distribution and loss of mercury during manufacture of such lamps (Table 3.42). The process of manufacture of luminescent lamps at Smolensk Electrical Lamp Plant is characterised by high absolute and specific losses of mercury, which made, during the examined period, 30-35% of the weight of used metal or 17-28 mg of mercury per conditioned lamp. Major losses take place on the luminescent lamps assembly lines, including mostly mechanical loss of mercury that is accumulated in the sewerage system traps wherefrom it is collected by the vacuum pumps and sent for secondary recycling (cleaning), as well as mercury contained in the de-mercuration slurry. Losses of mercury with broken glass and wastewater are not high. It should be noted that fine-dispersion metallic mercury fed to the mercury sewerage system (up to 3.6% of the weight of used metal) is not recorded by the plant analytical laboratory. At the same time, drops of metallic mercury can be seen visually in wastewater discharged to the city sewerage system; this mercury is lost irrecoverably, which may be due to the fact that the mercury traps are not efficient. At least 3-4% of the used amount of mercury is emitted to atmosphere basically as vapours. Table 3.41 Manufacture of luminescent lamps, use of mercury and generation of waste at the Smolensk Electrical Lamp Plant in 1998-2003
Table 3.41 (continued)
* The shop for manufacture of luminescent lamps was commissioned in 1970; in 1970-1975 the amount of mercury used here reached 6 t/year; ** Filters of the general exchange ventilation of the lamp assembly shop (activated carbon modified with iodine potassium; the filters have never been replaced; today their efficacy is 20-25%); *** The plant for de-mercuration (disposal) of rejected lamps, exhaust tubes, broken lamps, etc. (today, the product of their processing, i.e. mercury slurry with the concentration of mercury 60-75%, is transported in polyethylene bags to the enterprise's waste field where it is placed into temporary storage bins); **** After the filters of exchange ventilation; ***** After de-mercuration at the de-mercuration plant UDL-750 (broken glass is carried to the dumpsite where it is stored into temporary bins; ****** Only water-dissolved mercury (fine-dispersion metallic mercury fed finally to the sewerage system is not analysed); wastewater is discharged to the town sewerage system. In 2001, the Smolensk Electrical Lamp Plant used 2,596.09 kg of mercury; of which 1,765.34 kg were included into the conditioned products, and 830.75 kg were technological losses (68% and 32% of the total amount used, respectively). "Unaccounted losses" of mercury (33.7 kg) must, actually, be distributed pro rata among other kinds of metal loss. However, with account of data obtained from the Saransk Electrical Lamp Plant (see below), the distribution of the above losses can be presented as follows: 1 kg of mercury is emitted to the atmosphere as part of industrial dust; 3 kg of metal remains in the dust trapped by the treatment plants; 13.2 kg is accumulated in the mercury sewerage traps; 3.3 kg is lost in the sewerage system as fine-dispersion mercury; 0.006 kg is discharged with the wastewater (dissolved and suspended forms of metal); and 13.2 kg is degassed into the air of the room and (through door and window fenestrations, especially in warm seasons) emitted to the atmosphere, sorbed by construction elements, clothes and footwear of the workers, etc. Table 3.42 Balance of mercury distribution at Smolensk Electrical Lamp Plant (total use of mercury = 100%)
Table 3.42 (continued)
Table 3.42 (continued)
* Dissolved forms of mercury; ** Fine-dispersion metallic mercury fed to the sewerage system (calculations were made using data provided in (Stepanov, 1997)); *** Overwhelming majority (up to 95%, as shown below b)y the data for the Saransk Electrical Lamp Plant) is made by metallic mercury captured by the mercury sewerage traps (the so-called mechanical mercury losses). The rated balance of distribution of mercury losses at the Smolensk Electrical Lamp Plant for 2001 is given in Table 3.43. Major part of losses includes mechanical losses captured by the mercury sewerage traps; a significant part of mercury is removed from rejected products; over 102 kg of mercury (3.9% of its total use) is emitted to the atmosphere; almost 97 kg (3.7%) is fed to the sewerage system; more than 226 kg (8.7%) is carried to the plant's waste field (for temporary storage). Thus, eventually more than 425 kg of mercury is emitted/discharged to the environment, i.e. almost 16.4% of the amount used in the technological process; more than 199 kg of mercury (about 7.7% of the total use) is dissipated in the habitat and lost forever. Certain efforts on improvement of technology, first of all improvement of automatic dispensing machines, have been made in the recent years at Svet OJSC, which facilitates a significant reduction of specific mercury losses (Table 3.44). Saransk Electrical Lamp Plant (Lisma-SELZ), due to its technological processes, is characterised by a high use of mercury, higher absolute and specific losses of mercury and, hence, by more complicated satiation and hygienic conditions [4]. At this enterprise, they manufactured 35,000,000 conditioned luminescent lamps in 2001, using 3,903 kg of mercury. Planned use of metallic mercury for manufacture of one lamp, according to calculations based on the maximum allowed emissions/discharge (Draft Standards ..., 2000), makes 101.14 mg; of this amount 30-40% of mercury (35% on the average) were lost during technological processes (mainly due to substandard operation of automatic dispensing machines). Thus, 65.74 mg of mercury is used for one luminescent lamp, while losses of mercury metal during manufacture of lamps reach 1,366 kg. Additionally, 236 kg of metal are present in 3,590,000 rejected lamps processed in 2001 at the installation de-mercuration plant UDL-750 (State Report on the Environmental Condition ... Republic of Mordovia..., 2002), i.e. total technological losses of mercury at Saransk Electrical Lamp Plant make about 1,602 kg. Table 3.43 Balance of technological losses of mercury at the Smolensk Electrical Lamp Plant, 2001
Table 3.44 Specific losses of mercury at Smolensk Electrical Lamp Plant
* Amount of mercury emitted to atmosphere is determined by the efficiency of the cleaning installations. Data for Smolensk Electrical Lamp Plant show that during technological processes about 4.5% of the total used amount of mercury is emitted to air, which makes for Saransk enterprise 176 kg of metal. Of this amount 22 kg of mercury is emitted to the atmosphere in the town directly (Summary Report on Protection of Atmospheric Air for 2001...), and 154 kg are captured by the carbon absorbers installed in the system of ventilation of the lamp assembly shop (over the last 10-15 years, the absorbers have been several times updated and even replaced; for example, in 2001 a new absorber was put into operations). By the available data (The State Report on the Environmental Conditions of the Republic of Mordovia..., 2002), 1000 kg of spent mercury were collected and sent for recycling at Saransk Electrical Lamp Plant (basically, it was mercury lost mechanically during production processes and then extracted from the mercury sewerage traps). According to N.A. Stepanov (1997), on the average 3.6% of mercury used in production at Saransk Electrical Lamp Plant is fed to the sewerage system, bypassing the mercury traps, i.e. mainly as fine-dispersion metallic mercury. In 2001, such losses of mercury made 141 kg. Wastewater from the luminescent lamps assembly shop of Saransk Electrical Lamp Plant is discharged to the plant treatment installations and then (through the municipal sewerage system) to the treatment plants of the town of Saransk; after that, this wastewater id discharged to the Insar River. Annually, about 300 kg of sludge is generated at the local treatment plants of Saransk Electrical Lamp Plant; the average concentration of mercury in the sludge reaches 300 mg/kg (Yanin, 1998; Yanin, 2000a), i.e. it accumulated up to 90 kg of mercury. The levels of mercury in the sediments of wastewater generated at the municipal treatment plants (about 25,000 tonnes of dry substances a year) are 4 mg/kg on the average, i.e. it accumulated every year up to 100 kg of mercury, the significant part of which, surely, is brought with wastewater from Electrical Lamp Plant (Yanin, 1996, 2000a). About 15 kg of mercury is discharged annually from the municipal treatment plants to the Insar River The data presented allow getting the following balance of mercury distribution at Saransk Electrical Lamp Plant (Table 3.45). Table 3.45 The balance of mercury distribution at Saransk Electrical Lamp Plant in 2001 (the total use of mercury = 100%) *
Table 3.45 (continued)
* Such distribution of mercury is, mostly, typical of the enterprise operation in 1999-2002; ** In 1980's – early 1990's , the total use of mercury at the plant reached 5-5.5 t/year (Burenkov et al., 1993); *** Cleaning equipment of the lamp assembly shop (W-shaped absorbers are used containing 1 t of activated carbon that is sprinkled with hydrochloric acid from time to time); **** Mostly as fine-dispersion metallic mercury that is not captured by the mercury traps; ***** Mercury accumulated in the mercury sewerage traps; ****** De-mercuration slurry. As has been noted before, unaccounted mercury losses represent balance discrepancies in the calculations, which must be distributed pro rata among basic metal losses. Nevertheless, unaccounted losses of mercury can be related, to a significant degree, to unorganised emission of mercury vapours, sorption of vapours by the equipment and construction elements, clothes and footwear of the workers, dust generated during technological processes, as well as to broken glass. Thus, Saransk Electrical Lamp Plant emits to atmosphere about 68-70 tonnes of solid substances (industrial dust) a year, and about 240 tonnes of dust are captured by the cleaning equipment. The average concentration of mercury in the industrial dust generated by the enterprise makes 12 mg/kg (Yanin, 2003), i.e. it brings to the habitat up to 1 kg of mercury while about 3 kg of metal is present in dust captured by the cleaning plants; 24 kg of fine-dispersion mercury is lost to the sewerage system, 0.3 kg of dissolved mercury is discharged with wastewater, 0.2 kg is concentrated in broken glass, and 20.5 kg is degassed to the air of the rooms and (through door and window fenestrations) is emitted to the adjacent rooms and outside environment, sorbed by construction elements, clothes of workers, etc. Carrying of mercury on clothes and footwear of the workers is of certain hygienic importance. It has been established that children whose parents worked at Saransk Electrical Lamp Plant had much higher (3-5 times) levels of mercury in their hair as compared to children of parents employed at other enterprises of the town (Yanin, 2000b, 2000b). The calculated balance of mercury at Saransk Electrical Lamp Plant for 2001 in given in Table 3.46. As can be seen from the table, 43.5 kg of mercury (1.11% of the total weight of used metal) was emitted to atmosphere; over 165 kg (4.24%) was discharged to the sewerage system; 239 kg of mercury (over 10%) was included into the de-mercuration slurry, dust and broken glass and transported to the dumpsite; and 1,000 kg of unconditioned mercury was sent for recycling. Direct irrecoverable loss of metal (to atmosphere and the sewerage system) made 208.8 kg (5.4% of the total amount of used mercury). A substantial part of mercury emitted to atmosphere is precipitated directly within the enterprise area, where over the 40-year period of the plant operation up to 1 tonne of mercury has accumulated in the top level of the soil (Yanin, 1998). Specific losses of mercury and Saransk Electrical Lamp Plant are naturally much higher than at Smolensk Plant (Table 3.47). Table 3.46 Balance of technological losses of mercury at the Saransk Electrical Lamp Plant in 2001
Table 3.47 Specific losses of mercury during manufacture of luminescent lamps
Saransk and Smolensk Electrical Lamp Plants together used, in 2001, form manufacture of mercury lamps 6.5 tonnes of mercury, i.e. about 87% of the total amount of metal used by the Russian electrical lamps enterprises. The remaining part of mercury was used for manufacture of mercury lamps at Saransk Plant of Special Sources of Light and Electro-vacuum Glass ("SIS-EVS") and the enterprise Lisma-VNIIIS (totally about 500 kg) and at some other enterprises (also about 500 kg of mercury). For assessment of the balance of mercury at these enterprises the data on mercury distribution in the course of technological processes for Smolensk Plant were used (Table.3.48). Table 3.49 shows data characterising the total balance of mercury used in 2001 by Russian electrical lamp enterprises. As can be seen here, technological losses of metal are high, making 2,753 kg (36.7% of the total amount); of the, more than 1,007 kg of mercury were lost irrecoverably (emission to atmosphere, discharge to the sewerage system, disposal of solid waste at dumpsites) (Table 3.50). While solid waste carried to the dumpsites is placed, as a rule, in special bins that, to some extent, prevent migration of metal to the outside environment, then mercury emitted to atmosphere of discharged to the sewerage systems (totally about 0.5 tonnes) ultimately is dissipated in the habitat. Table 3.48 Balance of distribution of mercury at other Russian electrical lamps enterprises in 2001, kg
* Located nearby in the northern industrial area of the town of Saransk, up to 90% of mercury is used at SIS-EVS; ** Calculated for cleaning efficacy of 90%. Table 3.49 Balance of distribution of mercury among Russian electrical lamps enterprises in 2001, kg
* By available data, it is sent for recycling (cleaning); ** Today, basically placed to temporary storage bins at dumpsites; *** At some enterprises sorbents capturing dust sometime are replaced; the spent ones are sent for recycling; **** Captured dust is sent to dumpsites ***** Carried to the dumpsite where it is placed into temporary storage bins; ****** Mercury that is not captured by the mercury sewerage traps; ******* To the air of the working area and to outside environment Table 3.50 Emission/discharge of mercury to the environment from the electrical lamp enterprises, 2001
* 98.5% is vapour and gas fraction; ** 99.8% is fine-dispersion metallic mercury; *** 98.6% as part of the de-mercuration slurry. 3.8.2 Russian Market of Mercury LampsThe main users of lighting equipment in Russia are estimated as follows: industry – 50-55%; agriculture – 7-8%; administrative, trade and other public buildings – 10-11%; housing sector (including living houses) – 22-23%; outdoor lighting – about 1%; other – about 2% (Golembiovsky, Shemelin, 1997). Mercury lamps provide up to 60-65% of all artificial light generated in Russia. If we stem from the data of the FSU (Aizenberg, Prytkov), then today about 140 million lighting fixtures with low-pressure luminescent lamps are used in Russia as well as up to 13 million high-pressure discharge lamp lighting fixtures. In 2001, the share of domestic lamps made 40% in the retail trade, and the remaining part was imported (Problems of Contemporary Lighting, 2002). If we analyse the nomenclature of products offered by large Russian trade companies working with imported electrical lamp products, then a substantial share will be made by luminescent, arc, metal-halide, high-pressure sodium as well as compact luminescent lamps. Some foreign firms supply to Russia gas-discharge lamps for printing houses, television, etc. Electrical lamps are imported to Russia from 62 countries, including countries that do not have their own production facilities (like Australia, New Zeeland, Liechtenstein). Only in Moscow and in Moscow Region there are about 1900 commercial companies many of which practically sell only imported products and cover up to 50% of the local market (Aezenberg, Prytkov). In 2001, the Russian market selling foreign lighting sources was essentially determined by such firms as: Osram, Tungsram, General Electric, Silvania (Barinova et al., 2002; Russia: Market of Electrical Lamps ...; Problems of Contemporary Lighting ..., 2002) as well as Narva, OMS, BLV Licht, Vakuumtechnik, Aura, etc. It should be noted that efficacy of operation of mercury lamps manufactured by leading foreign firms is much higher than those manufactured by local enterprises; in addition, imported lamps have much smaller content of mercury. Precise data about Russian import and export of electrical lamps are not available. The annual reference books "Customs Statistics of Foreign Trade of the Russian Federation" do not subdivide export and import of electrical lamps by their types and is assessed in monetary equivalent, which does not make it possible to determine the real number of products. It can be only noted that the main importers to Russia of mercury lamps have been, in the recent years, Ukraine, Germany, Hungary, Poland, Taiwan and Finland (Customs Statistics ...,. 2001). Major part of Russian export of mercury lamps covers Finland, Lithuania and Kazakhstan, which, probably, is equal to several million items a year (conventionally it is 10 million items in 2001, containing about 500 kg of mercury). By the data of the association "Russian Light" which unites major part of Russian manufacturers of lighting equipment, supplies of foreign firms had exceeded, before August 1998, the scope of production of the four middle-size Russian electrical lamps enterprises (Russia, Market of Electrical Lamps ...). At that time Russia had 6 electrical lamp manufacturers – only two of them, in Saransk and Ufa (incandescent lamps), can be classified as large enterprises while the remaining four, Smolensk, Kalashnikov, Vladikavkaz and Tomsk, produced, together, about 170 million pieces of all types of lamps a year. If we take the estimates of the association "Russian Light", then the volume of import of electrical lamps to Russia was equal to this number. However, by the data of the same association, 42 million lamps were imported to Russian in 1998, and only 13 million pieces in 1999 (Russia: Market of Electrical Lamps ...). It should be noted that at the end of 1990's, in Russia, up to 45-55% of the market of imported electrical lighting equipment included the so-called "black market", whose substantial part was obvious smuggling (Golembiovsky, Shemelin). Moreover, the "black" import even now plays a great role on the Russian market of electrical lighting equipment (Aizenberg, Prytkovb). All stated above (with due account of the Russian demands) allows thinking that in 2001 several dozens of millions of mercury lamps of various types (up to 20-30 million items) were imported to Russia. With the average content of mercury per lamp at 20 mg (calculated by (Risk to Health and..., 2002)), this gives about 400-600 kg of mercury (500 kg on the average). Disposal of Used Mercury Lamps In 2001, less than 50 subjects of the Russian Federation had about 60 operating enterprises (de-mercuration stations or centres) which organised disposal of spent mercury lamps (first of all, luminescent lamps). Some regions of the country had organisations specialising in collection and transportation of spent mercury lamps to the place of their recycling (usually to neighbouring regions). About 30 Oblasts of Russia have regional and local regulatory acts determining the procedure for account, collection, storage, transportation and disposal of spent or faulty mercury lamps. Nevertheless, many regions of the country did not have any system of collection and disposal of used mercury lamps (the Northern Caucasus, some regions of the Central Russia, Republics of Karelia and Komi, Vologda, Kamchatka and Sakhalin oblasts, etc.). Analysis of the today's Russian system of disposal of mercury lamps suggests the following (Kosorukova, Yanin, 2002). Firstly, many Russian de-mercuration enterprises operate using not on a correct idea about the fact that all mercury in the spent luminescent lamps is in its elementary form. In particular, it was found out that that up to 95% of mercury in a used lamp is connected with luminophor and about 3-5% of metal of the total amount is connected with glass (Makarchenko et al., 2000; Doughty et al., 1995). In this case, luminophor acts as a sort of barrier, concentrating mercury in various forms, some of which are tightly connected with its matrix. Such behaviour of mercury can be explained by electro-chemical effects and presence in the working lamp tube of plasma "mercury/rarefied gas". Secondly, effectiveness of operation of de-mercuration stations is usually assessed in terms of prevention of possible mercury pollution of the habitat (simply speaking, the number of processed products). At the same time, enterprises disposing (recycling) mercury lamps represent environmentally hazardous facilities and, therefore, are obliged to carry their operation in conformity with the current requirements (Mercury. Standard ..., 1999, 2001). This demands regular analytical control (raw materials, production and environment control) to identify mercury and other ingredients; filling of certificates for the final products and waste; statistical account, including on the balance of raw materials, other materials, mercury and other pollutants. However, as a rule, all above conditions and requirements are not fulfilled in practice. Thirdly, none of the domestic de-mercuration stations is not ready technologically to obtain secondary (recycled) mercury from mercury lamps, which is substantially due to a high cost of the respective installation. The main final product obtained by recycling of mercury lamps is de-mercuration slurry (containing up to 60-75% of mercury), which is very rarely sent for recycling so as to extract metal. In the majority of cases, by all judgement, it is carried to waste fields and kept in the so-called temporary bins. In 2001, many domestic enterprises recycling mercury lamps used installations based on the thermal or thermo-vacuum method of processing (de-mercuration) of lamps – some of them used a hydrometallurgical method and only one used "dry and cold" pneumatic vibration technology. The hydrometallurgical method provides washing of mechanically ground luminescent lamps by a water solution and is based on redox reactions that theoretically explain transfer of elementary mercury into hard-to-dissolve compounds or compounds that are easily recycled. In practice, they use a chlorine iron solution for this. From the chemical point of view, it should result in hard-to-dissolve calomel. However, the chlorine iron solution is effective only in relation to elementary mercury, while the spent luminescent lamps contain mercury in various compounds that are fixed mostly by means of luminophor and. partly, by glass. This defines the fact that the methods based on washing with water (which should be performed in strict tight conditions, which is never done in practice) include some reaction rates and a low degree of cleaning of luminophor and glass from mercury. In view of this, it is recommended that multiple washing of lamps should be done by solutions, which, however, does not preclude probability of redistribution of mercury between its three oxidation states (Hg0, Hg22+, Hg2+). Moreover, when tight conditions for the process are not guaranteed, especially during multiple washing, mercury can oxidise to bivalent form (Hg2+), transfer in significant amounts to the solution and form stable complexes, including bivalent mercuric chloride. All this demands creation of special systems for cleaning of washing water so as to obtain slurry with concentrated mercury extracted from water. This slurry (together with hard-to-dissolve precipitation) must be sent for further recycling. However in practice, as a rule, no expensive cleaning systems are used and the washing water with mercury is discharged into the municipal sewerage system. Residues of glass, luminophor and metal parts that were not properly washed from mercury are carried to dumpsites. This practically ends the process, which in fact only imitates de-mercuration of mercury lamps. The thermal method of recycling of mercury lamps is based on sublimation of mercury from a mixture of glass and metal scrap followed by capture and condensation of its vapours. It makes the basis of the domestic installations UDL-100, UDL-15- and UDL-750 (designed by the former VNIIVMR, now NICPURO) and UDM-3000, UDMP-630 (NKP "Merkuriy"). The thermo-vacuum method is used in the installation of the type URL-2m (firm "FID-DUBNA"), which operated using the principle of vacuum distillation of mercury and its vapours are frozen on the surface of a cryogenic trap. Despite define advantages of both methods broadly promoted in Russia and the environmental cleanness of the technological process and de-mercuration installations as a whole declared by their authors (Mercury. Catalogue of Products ..., 1999), the latter, nevertheless, are complicated for operation. They require a lot of energy, high temperature, safe system for sorption of mercury from emitted gases, do not exclude probable emission of gases to atmosphere in case of loss of tightness in the joints of technological lines, etc. They have one more disadvantage, i.e. not only de-mercury process slurry is formed, but also some other final products, which results in partial dissipation of mercury extracted from lamps and its entering the habitat (Kosorukova, Yanin, 2002). At present, many countries of the world make practical use of methods of disposal of mercury lamps based on the following principles: 1) non-use of high-temperature and "wet" technologies, i.e. during lamp recycling no emission or discharge is made to the environment, which substantially reduces probability of secondary pollution of the habitat with mercury and other pollutants; 2) getting as little as possible amount of final reprocessing products, which sharply reduced probability of "dissipation" of mercury by different materials; 30 taking into account the fact that mercury in spent lamps is mostly bound with luminophor, which makes it necessary to separate it and transfer into a sort of raw material for obtaining secondary mercury. In our country, such "cold and dry" pneumatic vibration technology designed for recycling of luminescent lamps was developed and put into practice in the early 1990's at the "Ecotrom-2" plant, whose principle of operation is based on separation of lamps into principal components: broken glass, aluminium bases and luminophor containing mercury. Separation of luminophor – the main depositor of mercury – from glass is effected by blowing and suction of luminophor inside counter-moving systems "broken glass-air" in conditions of vibration. Glass is fed to a special bin wherefrom it is removed by means of pneumatic transport to a special accumulating container. Air is cleaned, step-by-step, from luminophor (cyclone, sleeve filter, cassette filter, enterprise absorber, shop absorber, sanitary absorber). Luminophor is blown off the sleeve filters by compressed air. Mercury-containing luminophor as well as spent activated carbon from the cleaning systems, cleaning rugs, etc., are mixed with cement and water solutions (generated during the process of de-mercuration of the working areas for sanitary and hygiene purposes and accumulated in a special container) and treated with a special substance that converts most of the mercury into its stable form, i.e. mercury sulphide. Balance calculations demonstrate that this technology allows extracting up to 95-96% of mercury from the lamps and bind it reliably. By the data provided by the users of such plant, the resultant cement and luminophor mixture, packed into polyethylene bags, is sent for recycling to obtain secondary mercury; ground glass is sent to enterprises making construction blocks; and aluminium bases are used as secondary raw materials. In 1999-2002, about 7 million mercury lamps (mainly luminescent lamps) were recycled in Moscow City and Moscow Oblast. Besides, this region has several thousands of small enterprises and organisations that generate, annually, at least 2.5 million spent luminescent lamps that are not recycled due to the complex process of their assembly, but rather stored indoors or carried to dumpsites (Kornitskaya, Rostokinskaya, 1999). Thus, at least 9.5 million mercury lamps are used during a year in the City of Moscow and Moscow Oblast (i.e. about 0.7 lamp per urban dweller). If we calculate, using the same indicator, the annual number of mercury lamps out of use in Chuvashia, where, like in Moscow, the system of their collection and disposal is well organised, then we get 673,000 lamps. It is indicative that, by the data available (Kartuzov, Shemanayev, 2000), here (in Cheboksary) up 700,000 lamps are recycled every year (including a small number of lamps from the neighbouring regions). In Bashkiria, 1.5 million lamps were disposed over the first 9 months of 2001 (Sheveleva), which gives, with such rates, about 1.9 million lamps a year (about 0.7 lamp per urban dweller of the republic). The obtained specific indictor (about 0.7 lamp per urban dweller) can, probably, be used to calculate the number of spent lamps for other regions of the country and for Russia in general. Calculations show that in Russia, in the recent years, about 72 million mercury lamps are used up (of them, about 3 million are high-pressure lamps). These lamps (basically domestically produced) contain at least 4 tonnes of mercury. Comparison of data on the number of used mercury lamps, obtained buy calculations, with the real numbers of accounted, stored and disposed products (in about 30 Russian regions), shows that in 2001 about 40% of spent mercury lamps (mainly luminescent lamps) were recycled at de-mercuration station, 20% were placed into special stores at enterprises and in organisations, and the remaining 40% were finally brought to landfills. It is assumed that the lamps break when they are disposed of to landfills and about 5% of the mercury (mercury in the gas phase) is immediately released to the atmosphere. The remaining mercury may sooner or later be release to the environment from the landfills, but no data has been available on mercury releases from landfills. Location of major Russian plants producing mercury lamps, galvanic elements and thermometers is shown on Figure 3.13. Click here to see the figure.Figure 3.13 Location of facilities for production of lamps, batteries and thermometers Summary Therefore, in 2001 consumption of mercury for light sources production in Russia amounted to 7.5 t, of which more than 36% was lost during production. The summarized balance of mercury distribution during production and use of mercury lamps is presented on Figure 3.13. Figure 3.14 shows the scheme representing the balance of distribution of mercury during production and use of mercury lamps in Russia in 2001. Figure 3.14 Balance of distribution of mercury during production and use of mercury lamps in Russia in 2001
3.9 Switches and Other Electrical EquipmentMercury switches The electrical switch represents a device designed for switching of electrical circuits in carious installations, remote and automatic control systems, etc. In the USSR, mercury switches were broadly used, i.e. glass cylinders with soldered-in contacts containing a definite amount of metallic mercury. In the USSR (Russia), the main manufacturer of mercury switches was Klin Thermometer Enterprise; today it is called OJSC "Termopribor" (Table 3.51). In the second half of 1990's, mass-scale manufacture of mercury switches was terminated in Russia. Table 3.51 Content of mercury in basic types of switches manufactured in Russia (Nomenclature Reference Book ..., 1993; Report on Scientific Research devoted to the Topic "Study ..., 2000).
At present, mercury switches are still used, differently, in different long-term operated devices, including home electrical rings. By data provided by Ecotrom NPP, in the recent years, large enterprises and organisations (mainly from Moscow) have supplied up to 2000 mercury switches (sensors, pickups) a year for disposal. The number of such devices, used (and discarded) every year by the private sector and small organisations, cannot be counted. It can be assumed, with a great degree of convention, that the number of spent (not longer used) mercury switches in the country as a whole can reach several dozens thousands (containing at least 0.5 tonnes of mercury). Of this amount, not more than 10-15%, i.e. about 400 kg of mercury are finally sent to waste dumpsites. By the data available (Substances Flow Analysis of Mercury in Products, 2001), in 2001 in USA, practically every manufactured motor vehicle had mercury switches (located under the bonnet and under the trunk cover); their number being 14 million pieces. The average amount of mercury in one motor vehicle switch is about 0.8 g. In 2002, import of cars to Russia was 127,000 (BIKI, 2003, No. 20). The share of motor vehicles delivered every year form USA does not exceed 5%. However, it cannot be excluded that motor vehicles imported from other countries may also have mercury sensors (including the alarm. Hence, it follows that at least several dozens kilos of mercury can be brought to Russia with such products. Mercury valves The mercury valve is a generalised name for ion devices producing arc discharge, sending current one way only, having one cathode filled with liquid mercury, with one (single-anode valve) or several (multi-anode valve) working anodes and one or several auxiliary electrodes used for igniting the arc. According to the method of control of arc discharge ignition mercury valves are divided into ignitrons (with an auxiliary electrode controlling the ignition of the main arc discharge) and excitrons (with a single excitation of the cathode spot). Ignitrons are used in ion electrical drives, pulsed modulators, electrical welding equipment, as well as in various switching devices. Excitrons are used for conversion of industrial and elevated frequency current as well as switching devices in inductive accumulators of energy in linear modulators. A multi-anode mercury valve or a set of anode mercury valves, made as a single structural unit designed for conversion of alternating current to direct current is called a mercury rectifier. Before the 1980's mercury rectifiers had been widely use d in industrial installations (rectifying units) of various power and various purpose, on transport traction substations (servicing tram and trolleybus lines, metro and railways), on long-distance alternating current electrical locomotives, for switching and regulation of current in welding machines, for electrolysis in nonferrous metallurgy and chemical industry, etc. The content of mercury in ignitrons varies from 10-250 g to 2-5 kg. For example, in ignitrons of types È-70, È-140, È-200 and È-350 the amount of mercury varies from 0.25 to 1 kg. In the former USSR, mercury valves and mercury rectifiers were manufactured, at different times, at Togliatti Electrical Engineering Plant (the town of Togliatti), Tallinn Plant of Mercury Rectifiers (town of Tallinn), Taganrog Metallurgy Plant (town of Taganrog), Electrosila plant (St. Petersburg), Electrovypryamitel (town of Saransk), Dynamo enterprise (Moscow), Uralelectrotyazhmash (town of Yekaterinburg), etc. At the end of 1970's, mass-scale (industrial) manufacture of mercury valves and rectifiers was terminated. In many respects, it was due to the fact that in 1960-1970's, in the USSR, mercury rectifiers were replaced by solid semiconductor rectifiers in transport traction substations and in various industrial plants. Nevertheless, some enterprise still continue to use installations with mercury valves (especially ignitrons). Moreover, according to data of the customs statistics (Customs Statistics ..., 2000), as early as in 1990 Russia imported some amounts of ignitrons and mercury rectifiers. Internet contains some ads, stating for example that a joint Belarusian-Lithuanian venture "Bel-Oka" offers for sale in Russia mercury rectifiers with a liquid-metal cathode and mercury rectifiers with directly heated cathodes. There are also data stating that some Russian enterprises manufacture mercury valves (ignitrons) by special orders in small amounts. However, judging by information available, the total output does not exceed several dozens devices a year, using up to 150-200 kg of metallic mercury. It should be noted that many enterprises store unused mercury valves in warehouses and from time to time submit them for disposal. For example, in 1999-2002, every year up to 300 ignitrons were received by Exotrom NPP (Moscow) from different Moscow organizations and enterprises, which gave up to 130-140 kg of spent mercury. For the country as a whole this may make about 4,000 mercury valves a year, containing up to 3 tonnes of mercury, which is normally sent for treatment (purification) and then returned to production. Vacuum pumps In the past, mercury was widely used as a working liquid in vacuum mercury-vapour pumps, i.e. devices used for creation, increase and maintenance of vacuum. Vacuum mercury-vapour pumps were used in pump and storage battery facilities of different enterprises, but mainly for pumping of mercury systems (for example, mercury rectifiers, as well as in research laboratories. Amount of mercury contained in one vacuum mercury-vapour pump was up to 13-15 kg. Mercury if filled into pumps during their operation and use, manually through a funnel. During operational use of vacuum mercury-vapour pumps incidents are often, which is accompanied by emission of metallic mercury to the environment; these facts were often reported in the press (especially, in late 1980's). Usually, the content of mercury vapours in the air of the room where vacuum mercury-vapour pumps are used exceeds MAC. At present, vacuum mercury-vapour pumps are still used at some Russian enterprises. Summary The table 3.52 summarises the available data on mercury use by switches and other electrical equipment. Table 3.52 Hg consumption and release with production and use of other appliances, t
* A certain amount of Hg is used annually for filling of meteorological barometers and manometers (dozens of kilos?). 3.10 Production of Chemicals and Laboratory Use of Mercury in the Russian Federation3.10.1 Production of Mercury ChemicalsThere is no official statistical data on production and sale of mercury chemicals In Russia. The analysis of the existing Business-Books and advertisements indicates that the major mercury compound producers, who supply them to the domestic market, include Altaykhimprom OJSC (Slavgorod town), Kubantsvetmet CJSC (Krasnodar kray) and Merkom Ltd. (Moscow oblast) Mercury compunds are usually produced upon the direct requests from various enterprises and organizations. The Institute of Problems of Microelectronic Technologies and of Special Purity Substances (IPMT RAS), together with Rtut CJSC, have developed technologies for production of pure mercury compounds, such as Hg2(NO3)2 • 2H2O, Hg(NO3)2 &bull H2O, HgSO4, Hg2Cl2, HgO, etc. (http://extech.msk.su/expo/exibit/innov_98/org.texm...) At present, the existing capacities allow synthesizing up to 50 kg of the above compounds a month. Bashkir innovation centre Sodeystviye (Assistance) (city of Ufa) offers services for production of various mercury compounds within 1-2 days, including those that have already been marketed, like mercury nitrate Hg(II), mercury rodanite Hg(II), mercury sulphate Hg(II), acetic mercury Hg (II). Khimproyekt NPO (city of Ufa) offers for sale acetic mercury (II). Mercury oxide (II) and mercury chloride (I) are used mainly in industrial production (vynilchloride and galvanic elements respectively); other Hg-containing chemicals are likely used in laboratories. Production of mercury compounds at Kubantsvetmet CJSC Table 3.53 shows data about amounts of production of different mercury compounds at Kubantsvetmet CJSC, in 2001-2002. The bulk of these compounds is constituted by mercury chloride delivered to enterprises producing vinyl chloride (city of Volgograd). In 2003, about 500 kg of red mercury oxide and 120 kg of mercury chloride were produced upon the request of Energia OJSC (Yelets town). Table 3.53 Production of mercury compounds at Kubantsvetmet CJSC in 2001 and 2002, kg*
* Besides compounds included into the table, the produced might also be amidochloride mercury (II), fluoric mercury (I), fluoric mercury (II), pyroalkaliantimonide mercury (II), mercury sulphide (II). Transportation of mercury to the areas of production of mercury compounds is made using special cylinders (by trucks). Mercury compounds are produced basically using hydrochemical methods. Rooms at the facilities producing mercury compounds are equipped with carbon adsorbers, ARV and local mercury discharge system (with mercury traps). Spent sorbent and collected metallic mercury are delivered for recycling. Soft waste is generated during production of mercury compounds. In particular, production of 1 t of the compound consumes 1 kg of kapron or lavsan belting. Every year, about 20 kg of such waste is generated containing up to 2% of mercury (by weight). This waste is kept in acid-resistant and tight containers and is incinerated in the oven TVP-1. Production of mercury compounds at Merkom Ltd. Table 3.54 shows data about production of mercury compounds at Merkom Ltd. in 2001-2002. Table 3.54 Production of mercury compounds at the Merkom Ltd., kg
Production of mercury compounds is made basically through direct orders of organisations and enterprises. In particular, a greater part of mercury oxide was delivered to Energia OJSC (Yelets); other mercury compounds were produced mainly when ordered by organisations selling chemical reagents (including Moskhimreactiv). A small amount of artificial cinnabar was synthesised for the association of artists (St. Petersburg). 3.10.2 Application of Mercury Chemicals for Laboratory UseIn Soviet times, all chemicals, including mercury-containing ones, were purchased through Soyuzreachim system, which included organizations dealing with production and sale of these products. After the activity of this system had been stopped in 90-ies the domestic market was occupied by several dozens of companies reselling the chemicals. Production of mercury-containing chemicals in Russia in 2002 that are used in laboratories, amounted to at least some 1.8 tonnes (Table 3.55). Besides, some chemicals may be imported, but it has not been possible to obtain relyable information on imported chemicals. Total mercury content of mercury-containing laboratory chemicals produced in Russia in 2002 is about 1.2 tonnes. Mercury chemicals used as preservatives in vaccines are included in section 3.11. Table 3.55 Production of mercury chemicals in Russia in 2002 to be used for laboratory application
In 2001 there was several dozens of companies dealing with chemicals resale. The largest companies were: Reachim JSC (Moscow), Chimmed JSC (Moscow), NevaReactive (Saint Petersburg), and some other. Mercury and its compounds are classic analytic and catalytic reagents and have been used for a large variety of purposes. It should be noted, that mercury is used in laboratories not only as a chemical for analytical purposes, but also in diffusion vacuum pumps, mercury valves, thermometers, barometers, manometers, rheometers. These applications are included in the sections dealing with the use of mercury in measuring equipment. Below Table 3.56 presents a brief description of some of the uses of mercury chemicals in the laboratories and in analytical chemistry. Table 3.56 Uses of mercury chemicals in the laboratories and in analytical chemistry *
*Mercury and its compounds are also used for in chemistry of cyclopropane, laboratory electrochemistry and research practices for creation of electrochemical conduits, detection of unsaturation of organic compounds etc., some mercury compounds are used for analysis (amperometric titration) of thiocholine (sulphuric analogue of choline), quantitative determination of glutamine; ** the main producer in Russia is Ural Plant of Chemical Reagents (town of Verkhnyaya Pyshma, Sverdlovsk Oblast); An exact data on mercury-containing chemicals amount currently purchased by various companies for laboratory purposes in the particular year are not available, as in Russia there are no strict reporting requirements for chemical and research laboratories regarding annual use of mercury-containing chemicals and their fate. The total use of mercury (including mercury contained in chemicals) in laboratory practices in 2001 can be roughly estimated at 2-5 t/year with a best estimate of 3.5 t/year. Disposal of spent chemicals According to the Instruction on safety measures in chemical laboratories, laboratories should neutralize the mercury-containing wastes. After getting the wastes of the 4th danger class from hazardous wastes of the 1st danger class, the non sorted wastes are placed into containers (as a rule containers with names "organic" and "non-organic" waste) and then transported to the landfills. As a rule, big analytical centers follow the above described way. The small laboratories after neutralization discharge the reagent wastes (in strongly diluted solution) to the sewerage system. Based on the above mentioned information it could be roughly estimated that 2-5 t mercury per year is disposed of to landfills (less) and to the sewerage system. 3.11 Mercury-Containing PesticidesOrganomercuric compounds have been used as fungicides and seeds disinfectants, e.g. Granozan and its mixtures with hexachlorobenzene (mercurbenzene) and hexachlorocyclohexane (mercurhexane). Fourteen types of mercury-containing pesticides were used in Russia (Table 3.57). Table 3.57 Mercury seed disinfectants which were used in the USSR and Russia
3.11.1 Production.Production of the organomercuric pesticides in the USSR was initiated at Sintez Chemical Plant in Dzerzhinsk Nizhegorodskaya oblast – beginning with 5 tonnes in 1955 and reaching 200 t/year by 1960. In 20 years the production started coming down and in 1989 decreased to 50 tonnes of mercury-containing pesticides. Production of Granosan at this plant was shut down in 1989. 3.11.2 Current Regulations and Legal ActsThe cases of population poisoning with mercury containing pesticides had been reported till the 70-ies. Within 1958-1964, 422 persons have been reported to be poisoned with Granosan in Perm oblast (Sivkov I.G., 1965), Novosibirsk oblast (Bychkova N.A., 1973) and Chelyabinsk oblast (Gisj Yu. F., Pozner Z.A., 1970). In 2001 the fire at chemical pesticides warehouse in Orenbourg oblast caused mercury poisoning of 26 people. Mercury concentration in the atmospheric air 300 – 400 m far from the fire point made up 54 – 90 μg/m3 (MAC is 0.3 μg/m3), i.e. the norms were 300 times exceeded (official information of RF Ministry of Health, 10.12. 2001). The urgent need for Granosan prohibition was proclaimed at scientific conferences in Kiev by Mr. L.I. Medvedev as far back as 1957. The necessity for prohibition of Granosan being a substance with embryotoxic, gonadotoxic and cytogenetic effects was further grounded in dissertation of Mr. V.I. Vashakidze. Application of mercury containing pesticides was finally prohibited in 1991. In compliance with the Law of the Russian Federation on Safe Handling of Pesticides and Agricultural Chemicals No. 109-FL dated July 19, 1997. "the turnover of agricultural chemicals not included into the State Register of pesticides and agricultural chemicals permitted for application in the Russian Federation is prohibited. "The State Register of pesticides and agricultural chemicals..." published annually doesn't contain mercury containing pesticides. The Article 12 of the Law implicates procedures of the state registration of pesticides to be carried out by the State Chemical Commission – the interagency body under the Ministry of Agriculture. Destruction and neutralization of pesticides and pesticides containers is carried out in compliance with the Temporary Instructions on preparatory measures for burial of prohibited and nonapplicable in agriculture pesticides and pesticides containers". Pesticides allowable concentrations in the environment are presented in the Hygienic Norms of Pesticides Concentration in the Environment GN 1.1.546-96 issued by RF Ministry of Health. The document regulates the following Granosan's concentrations:
In 2002, RF Ministry of Health put in force new SanPiN 1.2.1077-01 "Hygienic requirements for storage, application and transportation of pesticides and incecticides". RF Ministry of Health has included Granosan into the List of occupational hazards adopted by the Resolution No. 1010 dated 10.02.2003 on Adoption of the List of occupational hazards under the affect of which the employees are recommended to take milk and equivalent foodstuffs as the preventive measure. The specialized institute on technology and economy of storage, transportation and mechanization of fertilizers application of RF Ministry of Agriculture (VNIPIagrochim, Ryazan city) issued the Recommendations on preparation of prohibited and nonapplicable pesticides for neutralization and burial, 1997. This document refers the mercury containing pesticides to the extremely hazardous class 1 (according to the ranking applied in Russia) and requires their burial in metallic containers. 3.11.3 Application of Mercury-containing pesticidesAccording to the data presented by the Yearbook of Rosgidromet Institute of Experimental Metheorology (Pesticides Monitoring..., 1999), the Granosan's application in several Russian regions constituted (tonnes of ethyl mercury chloride):in 1995 – 6.1 7 tonnes, in 1996 – 5.5 tonnes. This data is not comprehensive and doesn't reflect the actual scope of mercury containing pesticides application. In 2001 the Federal Center of the State Sanitary-Epidemiological Service of RF Ministry of Health through its regional branches collected the data on quantities of pesticides turnover, had singled out the mercury containing pesticides as separate item. In 2000 the mercury containing pesticides were still used in 15 regions (see Table 3.58), about 50 tonnes of Granosan were applied meaning that about 1 tonne of mercury (at average Hg concentration in Granosan equal to 2%) was released. In 2001, about 17 tonnes of Hg-containing pesticides were used in 4 areas of the country. There is no doubt, that the data for 2000 on Penza and Chita oblasts applied up to 12 tonnes of Granosan should be clarified. Besides, the data for 2001 on the regions where Granosan was applied in 2000 should be obtained. Table 3.58 Amounts of mercury containing pesticides applied in 2000 – 2001 (based on the data from the Questionnaire of FCGSEN of RF Ministry of Health "Status of the state sanitary-epidemiological control over pesticides and agrochemicals turnover")
N/A data not available The clear picture confirming a considerable decrease of mercury containing pesticides application is presented based on the data for Voronezh oblast (The Letter of Mr. M.I. Chubriko the Head Doctor of the State Sanitary-Epidemiological Service of Voronezh oblast dated May 15, 2003) where 17.4 tonnes of Granosan was used in 1998, 26.89 tonnes - in 1999, 3.78 tonnes - in 2000, and there have been no use since 2001. In spite of the Granosan use prohibition and absence of the mercury containing pesticides in the Register, there are some advertisements regarding Granosan sale e.g. in the Internet Site of the Russian biotechnological market and the Site of Business Advertisements - "Offer for sale - Granosan, 15 tonnes, in barrels 25 kg each) (medbiolink 2003). Analysis of the data on amounts of used pesticides provided in Table 3.58 indicates a clear discrepancy between 2001 and 2000 data. This is caused by lack of data for 8 out of 15 territories of Russia included into the table. In 2001 mercury containing pesticides were net used only in 3 territories, which had applied relatively small amounts of pesticides (up to 4 t/year). Therefore, it is assumed that 20-40 of Hg containing pesticides are still used annually in the country. 3.11.4 Storage Conditions for Mercury-Containing PesticidesUntil 1990 the greater part of pesticides was stored in the warehouses of Selkhozchemia Association. The data of the Scientific-Research Center for Resource and Wastes Management (NITsPURO) under RF Ministry of Economic Development and RF Ministry of Natural Resources indicate, that about 750 tonnes of mercury containing pesticides (about 10 tonnes of Hg) can possibly be stored within RF territory in present. Compared to other official data regarding amounts of mercury containing pesticides used, this figure may be understated. For instance, the Environmental Report of Rostov oblast for 1998 states that there are up to 550 tonnes of these substances in the oblast's territory. Table 3.58 presents the data from the Questionnaire of FCGSEN of RF Ministry of Health "Status of the state sanitary surveillance over pesticides and agrochemicals turnover" and from other organizations concerning amounts of the mercury containing pesticides stored in Russia. The data shows that a number of mercury containing pesticides exceeds 1,500 tonnes, a part of which is stored on the specialized landfills. This data is probably also incomplete. For example, after the comprehensive inventory in Tver oblast amount of the stored mercury containing pesticides increased from 34.7 registered in 1999 up to 43.8 tonnes in 2003. The amount of mercury containing pesticides stored in warehouses (except landfills) and requiring destruction or storage at the special landfills is supposed to exceed 1,000 tonnes, which contain about 20 tonnes of mercury. Table 3.59 Amount of mercury containing pesticides disposed in storage facilities and landfills in several regions of Russia
Under conditions of the market economy many agricultural chemistry enterprises ceased their activities, and the pesticides storage conditions therefore turned out to be out of the state control. The agricultural enterprises were not able to store pesticides properly and to ensure safety of the storage facilities. Various publications (Andreeva 2000, Garkusha and Laubgan 2000, Ivanov 1999, Sinoda, Michailova 2000, et. al) inform, that the greatest volumes (i.e. more than 10 tonnes) of the outdated mercury containing pesticides are stored in Altai kray, Krasnodar kray, Belgorodskaya, Voronezhskaya, Kurskaya, Kurganskaya, Novosibirskaya, Omskaya, Pskovskaya, Rostovskaya, Ryazanskaya, Saratovskaya, Sverdlovskaya, Smolenskaya, Tverskaya, Tulskaya, Yroslavskaya oblasts and republics of Mordovia, Bashkortostan and Tatarstan. At the same time, some north-west (Murmanskaya and Novgorodskaya oblasts, republics of Kerilia and Komi), north (Yakutia) and southern (Kalmikia, Ingushetia, Osetia) territories of Russia in the Far East (Sahalinskaya and Kamchatskaya oblasts) officially do not have mercury containing pesticides. A significant problem is the condition of pesticides storehouses and the clarification of exact number of stored mercury containing pesticides, as it is very difficult to take an inventory in small companies, most of which have become bankrupts and do not properly register the poisonous substances. The more precise number of the outdated pesticides, including mercury containing ones, is specified during inventories. For instance, in 2001 the UNEP Chemical Project of the State Chemical Commission of the Ministry of Agriculture and the Center of International Projects was implemented in 5 regions (Krasnodarsky kray, Ryazanskaya, Tverskaya, Bryanskaya, Voronezhskaya oblasts). In 2002 the inventory was carried out within ACAP in cooperation with the State Chemical Commission of the Ministry of Agriculture in 10 northern regions (Arhangelskaya, Murmanskaya, Magadanskaya, Tumenskaya, Omskaya, Kamchatskaya oblasts, Altai Kray, Krasnoyarsk Kray, republics of Comi, Yakutia-Saha). I.e. 15 regions have been inventoried within 2 years. For the two of the above oblasts – Tverskaya and Voronezhskaya - an additional information on mercury containing pesticides was obtained in May 2003. In order to specify the conditions of mercury containing pesticides storage the centre of the oblast – Tver City and several oblast's regions – was visited by the experts in May 2003. Description of mercury containing pesticides and their storage conditions in Tverskaya oblast are presented in the Annex 2. Tverskaya and Voronezhskaya oblasts represent the cases of inventory of the outdated pesticides and their storage conditions can be considered as relatively good. Effective activity on the outdated pesticides inventory in Krasnodar Kray (one of the main agricultural centers of Russia) was pointed out at the Seminar on the outdated pesticides, which was held for NIS countries in May 2003 by the Center of International Projects in the frameworks of UNEP Chemical Project. However, the mercury containing pesticides storage conditions in most other regions are much worse. Examples According to the State Sanitary-Epidemiological Service, Granosan was applied in several regions of Altai kray, 56% of 429 storehouses do not comply with sanitary requirements, 318 agricultural enterprises have no pesticides storehouses. More than one third of agricultural enterprises in Tulskaya oblast carried out the seed treatment. 400 tonnes of pesticides are accumulated in the oblast. 80% of the storehouses do not comply with sanitary requirements. In 2001 the State Sanitary-Epidemiological Service issued only 18% of sanitary certificates, i.e. 7% of the storehouses were certified. For the last years about 20 storehouses had been destroyed resulted in chemicals, incl. Granosan, releases to terrestrial environment or being stolen. New storehouses are not built, therefore the problem of the outdated pesticides utilization is not solved (the Sanitary Epidemiological Report of Tulskaya oblast, 2001). Kamchatskaya oblast, Kozelsky Granosan burial site situated 35 km to the north-east from Petropavlovsk is in a very poor condition. The mercury is detected in the mushrooms growing nearby. Kuryinsky Landfill situated 20 km from Kurya village in Altay Kray is in unsatisfactory condition. One of the pesticides storehouses in Volgograd oblast store as much as 59 tonnes of Granosan, and this site is easily accessible; the metallic containers have been rusted through. In 1976 the landfill for non-applicable pesticides was constructed near Bataisk city of Rostov oblast. In 1977 – 1978 this landfill legally accepted for the burial more than 1,500 tonnes of pests-killers collected from agricultural and other enterprises of the Northern Caucasus, including more than 500 tonnes of mercury containing Granosan (about 8 tonnes of Hg). Today, the landfill is closed. Moreover, since 90-ies the groundwater level in the landfill area had been considerably increased resulted in the landfill's basement flooding. This can cause migration of mercury containing and other toxic components in the groundwater. In total 114.5 tonnes of chemicals are subjected to utilization in Chelyabinsk oblast. According to the State Sanitary Epidemiological Service, the problem of pesticides utilization is increasingly aggravating from year to year. This is caused by decentralization of the storehouses, lack of proper control activities and repair funds, as well as absence of posssibility to deliver the pesticides for destruction outside oblast. The greater part of protectants is stored at three storehouses in due condition for 5–6 months. Then, during the preplant period granosan in waterproof packing has been being sold to the relevant agricultural enterprises for futher application. Many storehouses store the unknown pesticides packed in non-labeled containers. E.g., according to the State Sanitary-Epidemiological Service, amounts of such pesticides subjected to destruction constitute 250 tonnes in Orlovskaya oblast, 365 tonnes in Kurskaya oblast, 244 tonnes in Pskovskaya oblast and 211 tonnes in Tatarstan. Such pesticides may also include Granosan. Free access to Granosan in a number of RF regions has lead to the negative effects. The existing pesticides landfill is completely filled up. According to the Republican Veterinarian Department, 12 sheep were poisoned with Granosan 9 km from Kizil City – a capital of Tiva Republic. The adjacent Tos-Bulak mineral spring is endangered to mercury contamination (Novosti Russian News Agency –Siberia, January 31, 2003). 3.11.5 Mercury containing pesticides burial sitesIn Russia an authorized disposal of mercury containing pesticides takes place on the territories of manufacturing enterprise in Dzerzhinsk City ( Nizhegorodskaya oblast), Krasny Bor Specialized Landfill in Leningrad oblast, some other specialized landfills. Inspection of storage conditions of mercury containing wastes generated at Granosan production at Sintez Plant in 2002 (Ref.: the Statement on Environmental Compliance Monitoring in Sintez JSC conducted in 16.04.2002 by the State Control Department of MNR, Privolzhsky Federal District) showed, that Granosan production building and local treatment facilities are destroyed. The production buildings and treatment facilities are contaminated with mercury. The urgent need for degassing of the equipment installed in Granosan production facilities and buildings had been stressed. The asphalted platform, near the Granosan production building, stores 22 containers (1 m3 each) with mercury containing wastes (activated carbon with 5% mercury content). By the date of inspection, the containers hold 0.02 th. tonnes of mercury containing wastes, i.e. up to 1 tone of mercury. Wastes storage conditions do not correspond with the environmental requirements related to the containers protection from leakage. The wastes are being utilized. The project on transportation of the containers for utilization at NPP Kubantsvetmet CJSC has been elaborated. SPES Environmental NGO believes, that amounts of mercury containing wastes, as well as metallic mercury (which had been buried in metallic containers at the enterprises's territory since 1985 till 1989, and most probably during the following years), stored at Sintez JSC (Dzerzhinsk City, Nizhegorodskaya oblast) are significantly underestimated (Letter No.15 dated 11.03.2003). The mercury containing pesticides have been disposed at Krasny Bor Specialized Landfill since 1970. According to the landfill's representatives it is done by the following way. Firstly, a company should duly apply to Karsny Bor for the wastes disposal, indicating the wastes type and class of hazard. Having singed the agreement on wastes disposal, a company at own expenses should pack the wastes into the standard containers in compliance with the established rules. A standard container for wastes has not less than 10 mm thick walls 1.7 m x 1.0 m x 1.0 m. Inside the steel container there is a metallic grid covered with concrete layer over 5 am thick. Pesticides are placed on the container's bottom, and the space between package and the walls in filled with concrete. The external surface of the container should be resinificated. The container should be marked with indelible paint specifying name of the company, agreement No., waste type, net weight and gross weight, container hand over date. The weight of container with wastes should not exceed 3 tonnes. On the landfill the containers are placed in two tires in 70 m thick Cambrian clay layer. Wastes weight is pointed out in the wastes acceptance certificate. Control over soil and groundwater quality is carried out by means of three inspection wells located at the landfill and three wells outside (around the periphery) the landfill. The soil and water samples are taken from the wells regularly and analyzed for presence of pollutants, including mercury. During the whole history of the landfill functioning there were no cases of MAC exceeding for mercury or heavy metals concentration in soil, groundwater and air. 3.11.6 SummaryThe present information on mercury-containing pesticides and be summarised as follows: 1. In spite of the official prohibition, trade with mercury containing pesticides still exists in the Russian Federation. Approximately 20-40 tonnes are used annually in agriculture.2. It is difficult to estimate the exact volume of used pesticides. In 2000 approximately up to 50 tonnes of agrochemicals were used with a total mercury content of about 1 tonne which was finally released to the environment. 3. The exact number of mercury containing pesticides located in the storehouses is not known, but may reach about 100-1,000 tonnes, containing up to 20 tonnes of mercury. 4. Most of the storehouses located in rural areas are in emergency condition, the wastes are stored improperly. 5. The environment is seriously endangered at mercury containing pesticides storage sites, mercury distribution in the areas adjacent to storehouses and mercury containing wastes landfills is almost not controlled. 3.12 Other applicationsIn the following section other applications of mercury are briefly described. For these applications less detailed information have been obtained, either because the applications are marginally or because the information was difficult to obtain. For some of the applications information is partly closed because the products are used for both civilian and military purposes. The section covers:
3.12.1 Production of Lithium IsotopesTechnologies designed for production of pure substances (metals), based on the amalgam method, are known since rather long ago (Baymakov, Zhurin, 1977; Belyayev et al, 1969; Kozin, 1970, 1973). They were used for the industrial production of zinc and cadmium of high purity, for split of stable isotopes, as well as for production of extra-pure metals in pilot production facilities, scientific research and laboratories. The amalgam method requiring significant amounts of mercury was most widely used in industry for split of stable lithium isotopes (Andreyev et el., 1982). Isotope splitting, i.e. separation of one or several isotopes of a given element from their mixture, is performed in special installations – counter-flow columns. To obtain a degree of splitting that is higher than in a single operation, in such installations a part of the flow (stream) going out from the last stage and enriched with the target isotope is returned to the column, i.e. the so-called flow circulation is performed (Chemical Encyclopaedia ..., 1990). To circulate the flows, thermal or electro-chemical decomposition is used or reactions with auxiliary substances. Accumulation of the target isotope begins at the end of the column, where the contacting fractions or streams are brought out of the equilibrium state due to stream circulation. As a result, the enriched fraction of this stage contacts with a fraction that has somewhat higher content of the target isotope as compared to the depleted fraction carried away from this stage. The last redistribution of isotopes results in an increased concentration of the isotope as compared to the initial concentration in both fractions leaving this stage. As the process goes on, the enrichment at the end of the column becomes higher, and stages that are more remote from the stream circulation place are taken out of the equilibrium state, while the extent of the enriched part of the column grows. When the required split degree is reached at the end of the column, the final products is taken up. As a rule, due to low initial concentrations of the target isotope, the period of accumulation of the isotope (the so-called start-up period of the installation) makes hundreds and thousands of hours. In practice, split of stable isotope in the liquid-liquid system is used by the chemical exchange method (amalgam exchange method) (Andreyev et al., 1982). In this case, one of the liquids is a water or organic solution of any element salt, while the second liquid is an amalgam of the same element. Such systems allow easy counter-flow due to a large difference in density, possibility to perform physical separation of two liquids and a relatively simple handling of streams, since amalgams are easily obtained by electrochemical methods and even more easily degraded or exchange one metal for another metal available in the solution. It is precisely this amalgam exchange method has found its industrial use for separation of stable lithium isotopes (see Figure 3.15).
1 – Isotope exchange column; 2 – column for separation of lithium from amalgam; 3 - electrolyser; 4 – device for dissolution of NaBr; 5 – amalgam decomposer; 6 - evaporation; 7 – rectification column (Inscriptions in the diagram: Âîçäóõ = Air; Îðãàíè÷åñêèé ðàñòâîðèòåëü = Organic solvent) Figure 3.15. In this case, streams in the top end of the cascade are circulated by electrolysis of water solutions of lithium salts on the current mercury cathode. The obtained amalgam is fed to the isotope exchange column 1, while the water solution of the organic solvent is fed to the rectification column 7, which allows using this solvent several times. Circulation of the streams at the lower end of the column can be effected in different ways. The simplest method used for transfer of the lithium from the amalgam to the organic solvent is its decomposition by water oxidized by an acid, evaporation of the water solution of the salt, incineration and dissolution in the solvent. Another (continuous) method of stream circulation includes replacement of the lithium amalgam by the sodium, strontium or cadmium through the reaction: Li(Hg) + MeX1(2) ↔ Me(Hg) + LiX, where Me is the metal of the 1st or 2nd group of the periodic system. The reaction is performed in a separate column 2, after which follow devices 5 for decomposition of Me(Hg), evaporation and dissolution of Me1(2) in the organic solvent fed from the upper stream circulation system. Mercury obtained during decomposition of Me(Hg) is returned to the electrolyser. To decompose the amalgam at the end of the cascade right in 6Li, usually decomposing agents are used filled with graphite, pig iron or alloys, as well as electrochemical decomposition by applying a positive potential to the amalgam (Andreyev et al., 1982). Production of lithium isotopes by the amalgam exchange method requires significant amounts of mercury. Thus, analysis of the technological cycle at one of such enterprises, located in the city of Novosibirsk (the chemical concentrates plant)( demonstrated (Mercury in the Environment ..., 1995; Yagolnitser et al., 1995) that here, from mid 1990's, the total accounted mercury loss during production of lithium isotopes by the amalgam-exchange method, had made about 35 t/year, while the unaccounted loss has reached 5 t (Fig. 3.16). Of all accounted mercury loss about 1.6 tonnes were released to atmosphere, about 2 kg to the water environment and 33.5 t were in solid waste to be buried. The data indicates that large amounts of mercury may be present in waste dumps around the enterprise. Figure 3.16 Approximate structure of mercury loss in production of lithium isotopes by the amalgam-exchange method (Yagolnitser et al., 1995)
Data shown in Figure 3.16 allows calculations of relative mercury loss in the course of the above technological process (with the total loss about 40.2 t/year): with solid and pasty waste about 58.2%, with spent activated carbon about 23.8%, with emissions to atmosphere about 4.6%, with wastewater about 0.004%; the share of unaccounted loss (drained to soil) about 12.5%. Data on mercury consumption at the Novosibirsk enterprise of chemical concentrates in 2000-2002, as well as data on its emission to the habitat environment are not available in the accessible information sources. However, it is know that the Institute of Chemistry of Solid State and Mechanical Chemistry of the Siberian Department of the RAS (city of Novosibirsk) has developed (and by all evidence has put into practical use) a principally new method for separation of stable lithium isotopes that allowed reducing the production cycle, a substantial decrease of electricity use and several-fold reduction of the volume of the used mercury ("Delovoy Novosibirsk ..."). This, undoubtedly, made it possible to reduce irrecoverable loss of mercury, principally connected, most probably, with solid waste (spent activated carbon, resins, pasty waste), generated during the above production processes and subject to secondary processing (or safe burial). As reported (Shatalov, 2000), the Novosibirsk enterprise of chemical concentrates has recently made an agreement for processing of lithium waste from amalgam-exchange production in USA and now intends to produce hydroxide, carbonate and waterless lithium chloride and pure metal. 3.12.2 Production of Semiconductors Mercury is used for manufacture of semiconductor materials and using them to make a new generation of electronic and electronic-optical devices. The use of mercury in the technologies designed for manufacture of semiconductor materials and as an acceptor admixture for germanium alloying (applied in infrared devices) to attribute to it a hole-type conductance was started as early as in 1950's. Today, semiconductor materials based on compounds of the A2Â6 type that contain mercury are used to manufacture photo resistors, photodiodes, Hall sensors, high-sensitivity receivers of optical light (photo receivers, photo receiving devise and sets), and semiconductor lasers. Use of mercury for production of semiconductor materials Until recently, mercury-containing semiconductor materials mostly were represented by HgS, SeHg and TeHg (Melikhov, Lazarev, 1987; Nashelskiy, 1987; Pasynkov, Sorokin, 1986, Tairov, Tsvetkov). Then, it was established that compounds of the type A2B6 form, among themselves, a continuous series of solid solutions, the typical representatives of which were CdXHg1-XTe, CdXHg1-XSe, CdTeXSe1-X, Hg1-XMnXTe, Hg3In2Te6, possessing unique electro-physical characteristics (Bovina et al, 1999; Varavin et al, 2002; Kurbatov, 1999; Ponomarenko, Filachev, 2001; Sidorov et al, 2001). Of special interest among these compounds are solid solutions of cadmium and mercury telluride (Cd-Hg-Te), abbreviated in Russia as CMT, that are used now widely for manufacture of semiconductor materials (Bovina, Stafeyev, 1999; Kurbatov, 1999). CMT semiconductors are widely applied world-wide for a number of application among others thermal imaging, CO2 laser detection, FTIR spectroscopy, missile guidance and night vision. A mixture Cd-Hg-Te (CMT) forms, in certain conditions, crystals with a sphalerite structure, where one sub-lattice is totally occupied by tellurium atoms, while the second houses atoms of cadmium and mercury (Svitashev, Chikichev, 1996). Depending on the proportion in which atoms of cadmium and mercury are mixed in the metal sub-lattice, we can obtain crystals of CMT with any given wide of forbidden area in the interval 0-1.6 eV (at 4.2 K). The most important among CMT, from the practical point of view, are solid solutions CdXHg1-XTe. In the USSR, the semiconductor solid solution of CMT was for the first time (practically, in parallel with the scientists of Great Britain) synthesized and investigated by SA.D. Shnaider (Lvov University) (XVI International Conference...). In the USSR, methods for growth of CMT and making of photodiodes and photoresistors on its base were developed mainly in the NIIPF (today it is GNC "NPO Orion", Moscow) (Stafeyev, 2001). Already in 1970, CMT was used to manufacture single-element photoresistors that were supplied to many organizations of the USSR. Some time later they started to develop photoresistors at the enterprise "Sapfir", where they organized batch production of the USSR first photoreceiver based on CMT (Stafeyev, 2001). Rather quickly the methods designed to grow CMT using the developments of the FTI of the USSR AS, NPO "Orion", NPO "GIPO" (city of Kazan), Institute of Semiconductors of the AS of Ukraine were developed and used in the mass-scale production in the NPO "Giredmet" (Moscow) and also at the Plant of Pure Metals (town of Svetlovodsk, Ukraine) and the Experimental Chemical-Metallurgical Plant (city of Podolsk) Kurbatov, 1999; Ponomarenko, Filachev, 2001). The Plant of Pure Metals in Ukraine, by mid 1980's, started to manufacture large-size monocrystals of CMT of the required condition and in the required numbers. Today, this plant supplies its products basically to China and some other countries. The plant in the city of Podolsk produces materials for bi-dimensional photoreceiver structures of the photodiode type and for photomatrixes (Kurbatov, 1999). In 1970's, the GOI of S.I. Vavilov (city of St. Petersburg) manufactured photoreceivers and photoreceiving devices with sensitive elements from germanium alloyed with mercury (Kurbatov, 1999). At present, CMT are used to make matrixes of photosensitive elements that are components of photoreceivers (PR), single, linear and matrix photoreceiving devices (PRD), sensitive within the wave range of 1-20 μm (Bovina et al., 1999; Kurbatov, 1999; Ponomarenko, Filachev, 2001; Filachev et al., 2003). Photodiodes from CdXHg1-XTe are now the basic photosensitive element in the modern IR-technologies, devices for receiving pulses from the CO2 laser, etc. semiconductor lasers and photoreceivers, based on CMT, are essential components of the elemental base for fibre-optical communication lines. CdXHg1-XTe is used to manufacture uncooled photoresistors, range-finder IR imagers, heat direction- and range-finders, etc. When Hall sensors are manufactured, the best results are attained when using solid solutions of HgSe è HgTe – as plates or thin films. Mercury emission during production of semiconductor materials Due to known circumstances, information about the scales of mercury use for manufacture of CMT and other semiconductor materials in Russia and in other countries of the worlds is not published; at least, such information is not present in the available literature. The same reasons explain why there are no data on environmental aspects of production of mercury-containing semiconductor materials. According to data, obtained from the workers of the mercury enterprises in the former USSR, one plant of pure metals for semiconductors (city of Svetlovodsk, Ukraine) in 1980's ordered every month up to 300 kg of metallic mercury (i.e. up to 3.5 t/year). It should be noted that this period was a period of rather active industrial production of volume CMT crystals and, evidently, of pilot work on improvement of technologies and introduction of new methods for CMT production. Processes of production of such materials are highly technological, performed within a closed volume, and, as emphasized by authors of many publications, do not release harmful substances. Besides, such production facilities have a high level of disposal and reuse of spent materials (which is due, to a significant degree, to their high cost), used in the technological process. At the same time, some publications, for example, underline that "CMT epitaxy requires high use and disposal of toxic group" (Chikichev, 1996), although scales of such use of metal are not reported. It is known, that CMT technologies depend very much not only on the growth of mercury-containing compounds, but also on post-growth thermal treatment of the produced materials in the mercury vapours. Therefore, it cannot be ruled out that in the course of synthesis of semiconductor materials not only chambers are contaminated with the used mercury, but that it is fed to the production environment, for example, due to un-tight equipment, to which indicate available indirect data. In particular, The Institute of Physics of Semiconductors and the Design Technological Institute of Applied Microelectronics of the SB of the RSAS (Novosibirsk) have recently developed and patented a method for collection of mercury in the technological chamber at the molecular beam epitaxy installation and also designed the respective plant (http://prometeus.nsc.ru/patent/1997/210.ssi). The above method and the plant, as stated in the patent, increase efficiency of the technology designed for production of multi-layer fine-film coating, increase productivity of the process and secure environmentally clean production. In any case, out of the entire volume of mercury used for production of semiconductor materials an insignificant amount of mercury in included into the final products, a small amount is emitted to the production environment, and the bulk is trapped, disposed, refined and reused in production. It cannot be precluded that main loss of mercury happens not so much during production of semiconductor materials, but rather at the stage of its disposal and refining. No data are at present available for quantification of the use of mercury for production of semiconductors or the releases from the production. 3.12.3 Power Semiconductor DevicesSeveral Russian enterprises of the semiconductor industry manufacture (by individual orders) power semiconductor devices that are not mass-produced anymore, but still used at domestic enterprises. The use of such devices is due to the fact that electricity supply schemes of some enterprises do not allow, for different reasons (including technical ones), installation of modern devices. Every device of the older generation, used to supply direct current to the electricity network, use up to 8 kg of metallic mercury (in the insulation jacket). For example, one of the Russian enterprises manufacturing semiconductor devices used about 420 kg of metallic mercury (according to the material balance of raw materials) for manufacture of the indicated power semiconductor devices in 2001-2002. There are grounds to presume that similar products are also produced by some other domestic enterprises of the semiconductor industry. Hence, one can conclude that the total use of metallic mercury in the country for such purposes may be about 0.5-2.5 t/year. Mercury loss during production process (in fact, individual and manual) of such products, evidently, bears occasional nature and can hardly exceed 1-3% of the total used mercury (i.e. about 45-50 kg a year for the entire country). The majority of lost metal, by all judgment, finally ends in the sewerage systems or dumpsites. The level of content of mercury vapours in the working area during production of the above devices may reach the level of MAC. 3.12.4 Mercury Containing BiocidesMercury compounds have traditionally been used as desinfectants and preservatives for preparation of a number of medicines and vaccines and latex productsdisinfectants. The concerned medicines included antiseptics (mercury amidochloride, diiodide, dichloride monochloride, oxide), oxicianide, salicylate amidochloride, mercurial yellow ointment, mercurial grey ointment, mercurial - bismuthic ointment, mercury plaster and Sofradex nasal drops. In persuance the Order of Russian Ministry of Health (No. 82 of 23.03.98 ã.) preparations and pharmaceutical substances containing mercury and its compounds have been excluded from "the State Register of Medical Drugs allowed for medical use and industrial manufacture" (http://www.medin.ru/price/m1998_4.shtml). Nevertheless, Internet sites include ads for sale of "medicines and preparations" including mercury amido-chloride (white precipitation mercury), mercury dichloride, mercury monochloride (calomel), mercury oxy-cyanate, yellow mercury oxide (yellow precipitated mercury), mercury iodide (II) (pharm), which in the past were used as medicinal drugs and antiseptics. Beginning from about early 1990's, they started to use in practice the so-called "vituride", i.e. preparation including mercury (dichloride), allegedly as a universal preparation for treating a broad range of diseases. In particular, as stated by the inventors, it could be used for treating sugar diabetes, tumours, systemic lupus, psoriasis, bronchial asthma, rheumatoid arthritis; it possesses antiviral activity against AIDS, hydrophobia, herpes and cytomegalovirus infections, etc. {Vituride ..., 1985). Despite the fact that the RF Ministry of Health, in its special information letter of 31 March 1998, No. 2510/2871-98-32 "On the Vituride Preparation", not allowed for medical use, once again confirmed that this preparation was prohibited for health uses (http://www.medin.ru/price/m1998_4.shtml (03.05.2003)), it is still advertised and, by all evidence, used for medical purposes (Vituride: Unique Domestic Medicinal Preparation sodium 2-(ethylmercuriothio)benzoate Ethylmercury thiosalicylate – marketed as "Merthiolat", "Temirosal" or "Thiomersal" - is added to the vaccines as a preservative. The problems of use of this substance for production of diphtheria, tetanus toxoids, and pertussis vaccine (ÀÊÄÑ), diphtheria and tetanus toxoids, vaccine (ÀÄÑ) and ÀÄÑ-Ì or its analogue Imovax, as well as  hepatite and tetanus vaccines was widely discussed in Russian scientific publications. For ÀÊÄÑ vaccine production 1 ml of whooping-cough suspension should be added with 100 μg of this compound. A Merthiolat (0.005%) was used for production of Russian  hepatite vaccine by Combioteh company. Before use for vaccines production, the concentration of free Hg in Merthiolat should be controlled. Most of the vaccines used in Russia contain mertiolat in 1: 10 000 proportion, in  hepatite vaccine – 1: 2.0 000. Thus, one inoculative dose contains small amount of mertiolat. The total amount of mercury for preservation of vaccines has not been quantified, but is considered to be insignificant compared to other uses of ercury. Information on mercury supplies from plants producing the vaccines is not available. By 6.08.2003 no information on current use of mercury containing biocides in Russia has been found in related journals, statistical reference books and Internet. "Biocides for water-deluting paintwork materials review" prepared by specialists of SRI of Chemistry of Nizhny Novgorod University named after Lobachevsky points out, that present production of such materials in Russia doesn't employ mercury and they are produced basically using imported materials (www.snab.ru:8/01/lkm/02/06.html) 3.12.5 Other UsesThe following section includes scattered information on other uses of mercury, which have not been assessed in detail, but different information indicates that mercury is or has recently been used for the applications. Explosives Mercury fulminate Hg (ONC)2 obtained by interaction between ethanol and solution of Hg(NO3)2 in HNO3, is used as the initiator explosive substance for blasting caps (which include individual substance) and igniting caps (which include a mixture of initiator substances containing up to 16-28% of mercury fulminate). Television and radio engineering Small amounts of mercury are used in television and radio engineering. For example, in mid 1990's, the enterprise "Ekran" (city of Novosibirsk) emitted to the air system from the shop where colour tubes were exposed (through the general exchange ventilation) up to 70 kg of mercury a year (Yagolnitser et al., 1995). There are date showing that computers – electronic keys and flat monitors – include mercury (up to 0.0022% of their total weight) (http://www.physfac.bspu.secta.ru/mirror/izone/izon...). The electronic key, i.e. the switch element, with a high electrical resistance in the closed state and a small electrical resistance in the open state, is widely used in automatic devices, telemechanics, radio engineering, and computer equipment. It was recently reported that since 1 January 2006 it will be totally prohibited to use mercury in Europe in production of electronic equipment (http://www.rambler.ru/db/news/msg.html?mid=1773229&s=12). Paints Now, Russia has more than a dozen large paint producers which produced, in 2001, about 351,135 tonnes of different paints, lacquers and varnishes. Concrete data on the use of mercury for paint production are not published. Moreover, it is considered that at present mercury and its compounds are not used for production of paints and colours. Nevertheless, there are indirect data showing that mercury and its compounds, most probably, are used, in different amounts, for production of paints, lacquers and varnishes. E.g. there is information taht (Boratyrev et al., 1999) the largest Russian enterprise producing paints, lacquers and varnishes, annually discharges up to 60 kg of mercury salts together with wastewater to the Volga River. A case is known when in Tver Oblast about 1,200 litres of mercury-containing waste was discharged to a quarry; this waste included secondary paint product used for production of adhesive labels at Kamenka OJSC (Kouvshinovo town) (News. Battery. Ru – "Accumulator of News", 25.01.2001...). Also it was reported (http://uuu.narod.ru/money.htm), that mercury-containing paintsrare used to print Russian paper banknotes; these paintsinclude the so-called active amalgams so as to protect counterfeiting. It is thought that such protection is the best practical. Mirrors In recent years, data has been published in press about the use of mercury for production of mirrors, at least there can be seen ads on sale of domestic mirrors manufactured using the amalgam method. Hosehold application A specific form of mercury use is its household application. Indeed, the available materials show that population has at homes a significant amount of metallic mercury and its compounds. For example in 1999, in the city of Perm an environmental organization bought the metallic mercury from the citizens – within 6 months they bought from population about 0.3 tonnes of this metal (Environmental Condition and People's Health in Perm ...). Given such situation as typical for most of 89 Russian regions, the weight of mercury being at households' disposal, may constitute, at least, several tonnes. This mercury, by all evidence, not only kept by them, but also actively used for different purposes. Thus, for example, mass media regularly report about attempts of illegal sale of metallic mercury on the "black" market in different regions of the country; the amount of seized metal varies from 10-60 kg to 1.5 tonnes. Internet sites explain in details how to use metallic mercury to cover snoot hooks (different methods are offered to fishermen) or how to make mercury chloride. Internet as well as some known magazines (see for example, "Radiolyubitel" (Radio Amateur"), 1991, No. 7, p. 43) recommend Gershtein amalgam (fine lead saw dust mixed with metallic mercury in the ratio of 1.5 kg to 2 g) as a preparation fit for cold soldering of metals. The well known story about "red mercury" has been continued in the recent years, by different stories (especially through Internet) about fantastic properties of the so-called mercury TV and radio antennas making of which requires substantial amounts of mercury (up to 10 kg of mercury per antenna). All this raises new interest among people to metallic mercury and, hence, they are attempting to find it. hr align="left" width="25%">Footnotes[2] It shall be understood that a number of diaphragm chlor-alkali production facilities remained in other CIS countries, for instance in Ukraine (4 diaphragm facilities), Uzbekistan, Azerbaijan and Armenia. At the same time most of the mercury cell facilities except one small in Azerbaijan and one in Ukraine, remained in Russia. More over, compared to the former USSR, chlorine production rates were decreased at the remaining facilities in Russia, including the diaphragm ones. The JSC "Kaustic" in Volgograd was established as a mercury cell facility in 1968 and a diaphragm plant was established there in addition in 1984. Currently both plants are functioning. [3] Volgograd, Sterlitamak and Sayansk mercury cell plants use sodium chloride evaporated form the brine as a feedstock and at Kirovo-Chepetsk plant halite deposit salt dissolved in a spent anolyte is used as a feedstock. * Since 1976 and till about mid 1990's, mercury thermometers were also manufactured at the "Steklopribor" Plant (today CJSC "EUROGLASS") in the town of Golynki (Rudnyansky District, Smolensk Oblast). This enterprise used (during the last years of its operation) up to 19 tonnes of mercury annually. * All technological equipment was designed and manufactured directly at the enterprise (automatic glass-polishing machines for manufacture of parts and assembly of blank thermometers; high precision thermostats to mark basic points of the scale; vacuum plants for filling mercury to thermometers; etc.). Therefore, the literature, which contains detailed description of the technological process of manufacture of mercury thermometers, is not present in the library. According to available data, technical documents are kept at the enterprise in typewritten copies. Most of the products are manufactured according to specifications of the enterprise. [4] Now, the issues are under consideration to shut down the facility for manufacture of luminescent lamps at the Saransk Electrical Lamp Plant and dismantling of the lamps assembly shop, including de-mercuration procedures. It is planned to organise at another industrial site a new facility for manufacture of lamps, which will be, in many aspects, meeting the earlier design (Design, 1st stage..., 1993), of a higher capacity, however based on technologies with much smaller use of mercury. * With the amount of mercury used at 130 t/year, losses of mercury to the sewerage system make 755 kg; we can assume that when use of mercury is decreased to 24.191 t (the level of 2001). i.e. 5.27 times, losses of metal will also decrease by the same number of times (they will be 140.6 kg, which is actually equal to the amount of losses in 2001, as given in 28).
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