technologyComment of gold mine operation and refining (SE): OPEN PIT MINING: The ore is mined in four steps: drilling, blasting, loading and hauling. In the case of a surface mine, a pattern of holes is drilled in the pit and filled with explosives. The explosives are detonated in order to break up the ground so large shovels or front-end loaders can load it into haul trucks. ORE AND WASTE HAULAGE: The haul trucks transport the ore to various areas for processing. The grade and type of ore determine the processing method used. Higher-grade ores are taken to a mill. Lower grade ores are taken to leach pads. Some ores may be stockpiled for later processing. HEAP LEACHING: The ore is crushed or placed directly on lined leach pads where a dilute cyanide solution is applied to the surface of the heap. The solution percolates down through the ore, where it leaches the gold and flows to a central collection location. The solution is recovered in this closed system. The pregnant leach solution is fed to electrowinning cells and undergoes the same steps as described below from Electro-winning. ORE PROCESSING: Milling: The ore is fed into a series of grinding mills where steel balls grind the ore to a fine slurry or powder. Oxidization and leaching: Some types of ore require further processing before gold is recovered. In this case, the slurry is pressure-oxidized in an autoclave before going to the leaching tanks or a dry powder is fed through a roaster in which it is oxidized using heat before being sent to the leaching tanks as a slurry. The slurry is thickened and runs through a series of leaching tanks. The gold in the slurry adheres to carbon in the tanks. Stripping: The carbon is then moved into a stripping vessel where the gold is removed from the carbon by pumping a hot caustic solution through the carbon. The carbon is later recycled. Electro-winning: The gold-bearing solution is pumped through electro-winning cells or through a zinc precipitation circuit where the gold is recovered from the solution. Smelting: The gold is then melted in a furnace at about 1’064°C and poured into moulds, creating doré bars. Doré bars are unrefined gold bullion bars containing between 60% and 95% gold. References: Newmont (2004) How gold is mined. Newmont. Retrieved from http://www.newmont.com/en/gold/howmined/index.asp technologyComment of primary lead production from concentrate (GLO): There are two basic pyrometallurgical processes available for the production of lead from lead or mixed lead-zinc-sulphide concentrates: sinter oxidation / blast furnace reduction route or Direct Smelting Reduction Processes. Both processes are followed by a refining step to produce the final product with the required purity, and may also be used for concentrates mixed with secondary raw materials. SINTER OXIDATION / BLAST FURNACE REDUCTION: The sinter oxidation / blast furnace reduction involves two steps: 1) A sintering oxidative roast to remove sulphur with production of PbO; and 2) Blast furnace reduction of the sinter product. The objective of sintering lead concentrates is to remove as much sulphur as possible from the galena and the accompanying iron, zinc, and copper sulphides, while producing lump agglomerate with appropriate properties for subsequent reduction in the blast furnace (a type of a shaft furnace). As raw material feed, lead concentrates are blended with recycled sinter fines, secondary material and other process materials and pelletised in rotating drums. Pellets are fed onto sinter machine and ignited. The burning pellets are conveyed over a series of wind-boxes through which air is blown. Sulphur is oxidised to sulphur dioxide and the reaction generates enough heat to fuse and agglomerate the pellets. Sinter is charged to the blast furnace with metallurgical coke. Air and/or oxygen enriched air is injected and reacts with the coke to produce carbon monoxide. This generates sufficient heat to melt the charge. The gangue content of the furnace charge combines with the added fluxes or reagents to form a slag. For smelting bulk lead-zinc-concentrates and secondary material, frequently the Imperial Smelting Furnace is used. Here, hot sinter and pre-heated coke as well as hot briquettes are charged. Hot air is injected. The reduction of the metal oxides not only produces lead and slag but also zinc, which is volatile at the furnace operating temperature and passes out of the ISF with the furnace off-gases. The gases also contain some cadmium and lead. The furnace gases pass through a splash condenser in which a shower of molten lead quenches them and the metals are absorbed into the liquid lead, the zinc is refined by distillation. DIRECT SMELTING REDUCTION: The Direct Smelting Reduction Process does not carry out the sintering stage separately. Lead sulphide concentrates and secondary materials are charged directly to a furnace and are then melted and oxidised. Sulphur dioxide is formed and is collected, cleaned and converted to sulphuric acid. Carbon (coke or gas) and fluxing agents are added to the molten charge and lead oxide is reduced to lead, a slag is formed. Some zinc and cadmium are “fumed” off in the furnace, their oxides are captured in the abatement plant and recovered. Several processes are used for direct smelting of lead concentrates and some secondary material to produce crude lead and slag. Bath smelting processes are used: the ISA Smelt/Ausmelt furnaces (sometimes in combination with blast furnaces), Kaldo (TBRC) and QSL integrated processes are used in EU and Worldwide. The Kivcet integrated process is also used and is a flash smelting process. The ISA Smelt/Ausmelt furnaces and the QSL take moist, pelletised feed and the Kaldo and Kivcet use dried feed. REFINING: Lead bullion may contain varying amounts of copper, silver, bismuth, antimony, arsenic and tin. Lead recovered from secondary sources may contain similar impurities, but generally antimony and calcium dominate. There are two methods of refining crude lead: electrolytic refining and pyrometallurgical refining. Electrolytic refining uses anodes of de-copperised lead bullion and starter cathodes of pure lead. This is a high-cost process and is used infrequently. A pyrometallurgical refinery consists of a series of kettles, which are indirectly heated by oil or gas. Over a series of separation processes impurities and metal values are separated from the lead bouillon. Overall waste: The production of metals is related to the generation of several by-products, residues and wastes, which are also listed in the European Waste Catalogue (Council Decision 94/3/EEC). The ISF or direct smelting furnaces also are significant sources of solid slag. This slag has been subjected to high temperatures and generally contains low levels of leachable metals, consequently it may be used in construction. Solid residues also arise as the result of the treatment of liquid effluents. The main waste stream is gypsum waste (CaSO4) and metal hydroxides that are produced at the wastewater neutralisation plant. These wastes are considered to be a cross-media effect of these treatment techniques but many are recycled to pyrometallurgical process to recover the metals. Dust or sludge from the treatment of gases are used as raw materials for the production of other metals such as Ge, Ga, In and As, etc or can be returned to the smelter or into the leach circuit for the recovery of lead and zinc. Hg/Se residues arise at the pre-treatment of mercury or selenium streams from the gas cleaning stage. This solid waste stream amounts to approximately 40 - 120 t/y in a typical plant. Hg and Se can be recovered from these residues depending on the market for these metals. Overall emissions: The main emissions to air from zinc and lead production are sulphur dioxide, other sulphur compounds and acid mists; nitrogen oxides and other nitrogen compounds, metals and their compounds; dust; VOC and dioxins. Other pollutants are considered to be of negligible importance for the industry, partly because they are not present in the production process and partly because they are immediately neutralised (e.g. chlorine) or occur in very low concentrations. Emissions are to a large extent bound to dust (except cadmium, arsenic and mercury that can be present in the vapour phase). Metals and their compounds and materials in suspension are the main pollutants emitted to water. The metals concerned are Zn, Cd, Pb, Hg, Se, Cu, Ni, As, Co and Cr. Other significant substances are fluorides, chlorides and sulphates. Wastewater from the gas cleaning of the smelter and fluid-bed roasting stages are the most important sources. References: Sutherland C. A., Milner E. F., Kerby R. C., Teindl H. and Melin A. (1997) Lead. In: Ullmann's encyclopedia of industrial chemistry (ed. Anonymous). 5th edition on CD-ROM Edition. Wiley & Sons, London. IPPC (2001) Integrated Pollution Prevention and Control (IPPC); Reference Document on Best Available Techniques in the Non Ferrous Metals Industries. European Commission. Retrieved from http://www.jrc.es/pub/english.cgi/ 0/733169 technologyComment of primary zinc production from concentrate (RoW): The technological representativeness of this dataset is considered to be high as smelting methods for zinc are consistent in all regions. Refined zinc produced pyro-metallurgically represents less than 5% of global zinc production and less than 2% of this dataset. Electrometallurgical Smelting The main unit processes for electrometallurgical zinc smelting are roasting, leaching, purification, electrolysis, and melting. In both electrometallurgical and pyro-metallurgical zinc production routes, the first step is to remove the sulfur from the concentrate. Roasting or sintering achieves this. The concentrate is heated in a furnace with operating temperature above 900 °C (exothermic, autogenous process) to convert the zinc sulfide to calcine (zinc oxide). Simultaneously, sulfur reacts with oxygen to produce sulfur dioxide, which is subsequently converted to sulfuric acid in acid plants, usually located with zinc-smelting facilities. During the leaching process, the calcine is dissolved in dilute sulfuric acid solution (re-circulated back from the electrolysis cells) to produce aqueous zinc sulfate solution. The iron impurities dissolve as well and are precipitated out as jarosite or goethite in the presence of calcine and possibly ammonia. Jarosite and goethite are usually disposed of in tailing ponds. Adding zinc dust to the zinc sulfate solution facilitates purification. The purification of leachate leads to precipitation of cadmium, copper, and cobalt as metals. In electrolysis, the purified solution is electrolyzed between lead alloy anodes and aluminum cathodes. The high-purity zinc deposited on aluminum cathodes is stripped off, dried, melted, and cast into SHG zinc ingots (99.99 % zinc). Pyro-metallurgical Smelting The pyro-metallurgical smelting process is based on the reduction of zinc and lead oxides into metal with carbon in an imperial smelting furnace. The sinter, along with pre-heated coke, is charged from the top of the furnace and injected from below with pre-heated air. This ensures that temperature in the center of the furnace remains in the range of 1000-1500 °C. The coke is converted to carbon monoxide, and zinc and lead oxides are reduced to metallic zinc and lead. The liquid lead bullion is collected at the bottom of the furnace along with other metal impurities (copper, silver, and gold). Zinc in vapor form is collected from the top of the furnace along with other gases. Zinc vapor is then condensed into liquid zinc. The lead and cadmium impurities in zinc bullion are removed through a distillation process. The imperial smelting process is an energy-intensive process and produces zinc of lower purity than the electrometallurgical process. technologyComment of treatment of electronics scrap, metals recovery in copper smelter (SE, RoW): Conversion of Copper in a Kaldo Converter and treatment in converter aisle. technologyComment of treatment of scrap lead acid battery, remelting (RoW): The referred operation uses a shaft furnace with post combustion, which is the usual technology for secondary smelters. technologyComment of treatment of scrap lead acid battery, remelting (RER): The referred operation uses a shaft furnace with post combustion, which is the usual technology for secondary smelters. Typically this technology produces 5000 t / a sulphuric acid (15% concentration), 25’000 t lead bullion (98% Pb), 1200 t / a slags (1% Pb) and 3000 t / a raw lead matte (10% Pb) to be shipped to primary smelters. Overall Pb yield is typically 98.8% at the plant level and 99.8% after reworking the matte. The operation treats junk batteries and plates but also lead cable sheathing, drosses and sludges, leaded glass and balancing weights. From this feed it manufactures mainly antimonial lead up to 10% Sb, calcium-aluminium lead alloys with or without tin and soft lead with low and high copper content. All these products are the result of a refining and alloying step to meet the compliance with the designations desired. The following by products are reused in the process: fine dust, slag, and sulfuric acid. References: Quirijnen L. (1999) How to implement efficient local lead-acid battery recycling. In: Journal of Power Sources, 78(1-2), pp. 267-269.
technologyComment of gold mine operation and refining (SE): OPEN PIT MINING: The ore is mined in four steps: drilling, blasting, loading and hauling. In the case of a surface mine, a pattern of holes is drilled in the pit and filled with explosives. The explosives are detonated in order to break up the ground so large shovels or front-end loaders can load it into haul trucks. ORE AND WASTE HAULAGE: The haul trucks transport the ore to various areas for processing. The grade and type of ore determine the processing method used. Higher-grade ores are taken to a mill. Lower grade ores are taken to leach pads. Some ores may be stockpiled for later processing. HEAP LEACHING: The ore is crushed or placed directly on lined leach pads where a dilute cyanide solution is applied to the surface of the heap. The solution percolates down through the ore, where it leaches the gold and flows to a central collection location. The solution is recovered in this closed system. The pregnant leach solution is fed to electrowinning cells and undergoes the same steps as described below from Electro-winning. ORE PROCESSING: Milling: The ore is fed into a series of grinding mills where steel balls grind the ore to a fine slurry or powder. Oxidization and leaching: Some types of ore require further processing before gold is recovered. In this case, the slurry is pressure-oxidized in an autoclave before going to the leaching tanks or a dry powder is fed through a roaster in which it is oxidized using heat before being sent to the leaching tanks as a slurry. The slurry is thickened and runs through a series of leaching tanks. The gold in the slurry adheres to carbon in the tanks. Stripping: The carbon is then moved into a stripping vessel where the gold is removed from the carbon by pumping a hot caustic solution through the carbon. The carbon is later recycled. Electro-winning: The gold-bearing solution is pumped through electro-winning cells or through a zinc precipitation circuit where the gold is recovered from the solution. Smelting: The gold is then melted in a furnace at about 1’064°C and poured into moulds, creating doré bars. Doré bars are unrefined gold bullion bars containing between 60% and 95% gold. References: Newmont (2004) How gold is mined. Newmont. Retrieved from http://www.newmont.com/en/gold/howmined/index.asp technologyComment of gold-silver mine operation with refinery (PG): OPEN PIT MINING: The ore is mined in four steps: drilling, blasting, loading and hauling. In the case of a surface mine, a pattern of holes is drilled in the pit and filled with explosives. The explosives are detonated in order to break up the ground so large shovels or front-end loaders can load it into haul trucks. ORE AND WASTE HAULAGE: The haul trucks transport the ore to various areas for processing. The grade and type of ore determine the processing method used. Higher-grade ores are taken to a mill. Lower grade ores are taken to leach pads. Some ores may be stockpiled for later processing. HEAP LEACHING: The recovery processes of the Misima Mine are cyanide leach and carbon in pulp (CIP). The ore is crushed or placed directly on lined leach pads where a dilute cyanide solution is applied to the surface of the heap. The solution percolates down through the ore, where it leaches the gold and flows to a central collection location. The solution is recovered in this closed system. The pregnant leach solution is fed to electrowinning cells and undergoes the same steps as described below from Electro-winning. ORE PROCESSING: Milling: The ore is fed into a series of grinding mills where steel balls grind the ore to a fine slurry or powder. Oxidization and leaching: The recovery process in the Porgera Mine is pressure oxidation and cyanide leach. The slurry is pressure-oxidized in an autoclave before going to the leaching tanks or a dry powder is fed through a roaster in which it is oxidized using heat before being sent to the leaching tanks as a slurry. The slurry is thickened and runs through a series of leaching tanks. The gold in the slurry adheres to carbon in the tanks. Stripping: The carbon is then moved into a stripping vessel where the gold is removed from the carbon by pumping a hot caustic solution through the carbon. The carbon is later recycled. Electro-winning: The gold-bearing solution is pumped through electro-winning cells or through a zinc precipitation circuit where the gold is recovered from the solution. Smelting: The gold is then melted in a furnace at about 1’064°C and poured into moulds, creating doré bars. Doré bars are unrefined gold bullion bars containing between 60% and 95% gold. WATER SUPPLY: For Misima Mine, process water is supplied from pit dewatering bores and in-pit water. Potable water is sourced from boreholes in the coastal limestone. For Porgera Mine, the main water supply of the mine is the Waile Creek Dam, located approximately 7 kilometres from the mine. The reservoir has a capacity of approximately 717, 000 m3 of water. Water for the grinding circuit is also extracted from Kogai Creek, which is located adjacent to the grinding circuit. The mine operates four water treatment plants for potable water and five sewage treatment plants. ENERGY SUPPLY: For Misima Mine, electricity is produced by the mine on site or with own power generators, from diesel and heavy fuel oil. For Porgera Mine, electricity is produced by the mine on site. Assumed with Mobius / Wohlwill electrolysis. Porgera's principal source of power is supplied by a 73-kilometre transmission line from the gas fired and PJV-owned Hides Power Station. The station has a total output of 62 megawatts (“MW”). A back up diesel power station is located at the mine and has an output of 13MW. The average power requirement of the mine is about 60 MW. For both Misima and Porgera Mines, an 18 MW diesel fired power station supplies electrical power. Diesel was used in the station due to the unavailability of previously supplied heavy fuel oil. technologyComment of gold-silver mine operation with refinery (CA-QC): One of the modelled mine is an open-pit mine and the two others are underground. technologyComment of gold-silver mine operation with refinery (RoW): The mining of ore from open pit mines is considered. technologyComment of primary zinc production from concentrate (RoW): The technological representativeness of this dataset is considered to be high as smelting methods for zinc are consistent in all regions. Refined zinc produced pyro-metallurgically represents less than 5% of global zinc production and less than 2% of this dataset. Electrometallurgical Smelting The main unit processes for electrometallurgical zinc smelting are roasting, leaching, purification, electrolysis, and melting. In both electrometallurgical and pyro-metallurgical zinc production routes, the first step is to remove the sulfur from the concentrate. Roasting or sintering achieves this. The concentrate is heated in a furnace with operating temperature above 900 °C (exothermic, autogenous process) to convert the zinc sulfide to calcine (zinc oxide). Simultaneously, sulfur reacts with oxygen to produce sulfur dioxide, which is subsequently converted to sulfuric acid in acid plants, usually located with zinc-smelting facilities. During the leaching process, the calcine is dissolved in dilute sulfuric acid solution (re-circulated back from the electrolysis cells) to produce aqueous zinc sulfate solution. The iron impurities dissolve as well and are precipitated out as jarosite or goethite in the presence of calcine and possibly ammonia. Jarosite and goethite are usually disposed of in tailing ponds. Adding zinc dust to the zinc sulfate solution facilitates purification. The purification of leachate leads to precipitation of cadmium, copper, and cobalt as metals. In electrolysis, the purified solution is electrolyzed between lead alloy anodes and aluminum cathodes. The high-purity zinc deposited on aluminum cathodes is stripped off, dried, melted, and cast into SHG zinc ingots (99.99 % zinc). Pyro-metallurgical Smelting The pyro-metallurgical smelting process is based on the reduction of zinc and lead oxides into metal with carbon in an imperial smelting furnace. The sinter, along with pre-heated coke, is charged from the top of the furnace and injected from below with pre-heated air. This ensures that temperature in the center of the furnace remains in the range of 1000-1500 °C. The coke is converted to carbon monoxide, and zinc and lead oxides are reduced to metallic zinc and lead. The liquid lead bullion is collected at the bottom of the furnace along with other metal impurities (copper, silver, and gold). Zinc in vapor form is collected from the top of the furnace along with other gases. Zinc vapor is then condensed into liquid zinc. The lead and cadmium impurities in zinc bullion are removed through a distillation process. The imperial smelting process is an energy-intensive process and produces zinc of lower purity than the electrometallurgical process. technologyComment of processing of anode slime from electrorefining of copper, anode (GLO): Based on typical current technology. Anode slime treatment by pressure leaching and top blown rotary converter. Production of Silver by Möbius Electrolysis, Gold by Wohlwill electrolysis, copper telluride cement and crude selenium to further processing. technologyComment of silver-gold mine operation with refinery (CL): OPEN PIT MINING: The ore is mined in four steps: drilling, blasting, loading and hauling. In the case of a surface mine, a pattern of holes is drilled in the pit and filled with explosives. The explosives are detonated in order to break up the ground so large shovels or front-end loaders can load it into haul trucks. BENEFICIATION: The processing plant consists of primary crushing, a pre-crushing circuit, (semi autogenous ball mill crushing) grinding, leaching, filtering and washing, Merrill-Crowe plant and doré refinery. The Merrill-Crowe metal recovery circuit is better than a carbon-in-pulp system for the high-grade silver material. Tailings are filtered to recover excess water as well as residual cyanide and metals. A dry tailings disposal system was preferred to a conventional wet tailings impoundment because of site-specific environmental considerations. technologyComment of silver-gold mine operation with refinery (RoW): Refinement is estimated with electrolysis-data. technologyComment of treatment of crust from Parkes process for lead production (GLO): Processing of Parkes desilvering crust by hot pressing, dezincing (vacuum distillation), cupellation of lead and moebius electrolysis (electrowinning) technologyComment of treatment of precious metal from electronics scrap, in anode slime, precious metal extraction (SE, RoW): Anode slime treatment by pressure leaching and top blown rotary converter. Production of Silver by Möbius Electrolysis, Gold by Wohlwill electrolysis, Palladium to further processing technologyComment of treatment of waste x-ray film (GLO): None
technologyComment of gold mine operation and refining (SE): OPEN PIT MINING: The ore is mined in four steps: drilling, blasting, loading and hauling. In the case of a surface mine, a pattern of holes is drilled in the pit and filled with explosives. The explosives are detonated in order to break up the ground so large shovels or front-end loaders can load it into haul trucks. ORE AND WASTE HAULAGE: The haul trucks transport the ore to various areas for processing. The grade and type of ore determine the processing method used. Higher-grade ores are taken to a mill. Lower grade ores are taken to leach pads. Some ores may be stockpiled for later processing. HEAP LEACHING: The ore is crushed or placed directly on lined leach pads where a dilute cyanide solution is applied to the surface of the heap. The solution percolates down through the ore, where it leaches the gold and flows to a central collection location. The solution is recovered in this closed system. The pregnant leach solution is fed to electrowinning cells and undergoes the same steps as described below from Electro-winning. ORE PROCESSING: Milling: The ore is fed into a series of grinding mills where steel balls grind the ore to a fine slurry or powder. Oxidization and leaching: Some types of ore require further processing before gold is recovered. In this case, the slurry is pressure-oxidized in an autoclave before going to the leaching tanks or a dry powder is fed through a roaster in which it is oxidized using heat before being sent to the leaching tanks as a slurry. The slurry is thickened and runs through a series of leaching tanks. The gold in the slurry adheres to carbon in the tanks. Stripping: The carbon is then moved into a stripping vessel where the gold is removed from the carbon by pumping a hot caustic solution through the carbon. The carbon is later recycled. Electro-winning: The gold-bearing solution is pumped through electro-winning cells or through a zinc precipitation circuit where the gold is recovered from the solution. Smelting: The gold is then melted in a furnace at about 1’064°C and poured into moulds, creating doré bars. Doré bars are unrefined gold bullion bars containing between 60% and 95% gold. References: Newmont (2004) How gold is mined. Newmont. Retrieved from http://www.newmont.com/en/gold/howmined/index.asp technologyComment of primary zinc production from concentrate (CA-QC): Hydrometallurgical process Sulphide concentrates are roasted first in fluidized bed roasters to produce zinc oxide (calcine) and sulphur dioxide. Roasting is an exothermic process and no additional fuel is used to sustain the reaction, the heat generated is recovered to produce steam. Calcine is then sent to the leaching step. Roaster gases are treated in hot electrostatics precipitators to remove dust. The remaining dust and volatile metals such as mercury and selenium are removed in the wet section of the acid plant through a cooling tour, a mist precipitator and a mercury tower (Boliden mercury removal processs). The sulphur dioxide is then converted to sulphuric acid in a conventional recovery system (converted and absorbing tower). Leaching of the calcine is carried out in a number of successive stages using a gradually increasing strength of hot sulphuric acid. The initial stages dissolve the major part of the zinc oxide and the other stages dissolve the zinc ferrite (ZnO.Fe2O3) and convert iron into Jarosite (sodium Jarosite). Zinc sulfate (ZnSO4) entering the electrolysis stage produce electrolyte (H2SO4) that is returned to leaching plant. Other metals are also dissolved during the process and are removed after leaching. Iron is the major impurity, which is precipitated in the form of Jarosite. Overall waste: The production of metals is related to the generation of several by-products, residues and wastes. Relatively large quantities of iron based solids, depending on the iron content, are generated by the leaching process (6.14E-1 kg Jarosite/kg zinc). Cement is added to the Jarosite to produce Jarofix (an inert waste). Solid residues also arise as the result of the liquid effluents treatment. The main waste stream is gypsum (CaSO4) and metal hydroxides that are produced at the wastewater neutralization plant. Mercury and selenium residues arise from the weak acid bleed treatment from the acid plant. Selenium can be recovered from these residues depending on the market demand for this metal. Overall emissions: The emissions to air can either be stack emissions or fugitive emissions. Stack emissions are normally monitored continuously (SO2) or periodically (other emissions) and reported. The main emissions to air from zinc production are sulphur dioxide (SO2) and particulate matters including metals. Main emissions to water are metals and their compounds. The monitored metals are zinc, cadmium, lead, mercury, selenium, copper and arsenic. technologyComment of primary zinc production from concentrate (RoW): The technological representativeness of this dataset is considered to be high as smelting methods for zinc are consistent in all regions. Refined zinc produced pyro-metallurgically represents less than 5% of global zinc production and less than 2% of this dataset. Electrometallurgical Smelting The main unit processes for electrometallurgical zinc smelting are roasting, leaching, purification, electrolysis, and melting. In both electrometallurgical and pyro-metallurgical zinc production routes, the first step is to remove the sulfur from the concentrate. Roasting or sintering achieves this. The concentrate is heated in a furnace with operating temperature above 900 °C (exothermic, autogenous process) to convert the zinc sulfide to calcine (zinc oxide). Simultaneously, sulfur reacts with oxygen to produce sulfur dioxide, which is subsequently converted to sulfuric acid in acid plants, usually located with zinc-smelting facilities. During the leaching process, the calcine is dissolved in dilute sulfuric acid solution (re-circulated back from the electrolysis cells) to produce aqueous zinc sulfate solution. The iron impurities dissolve as well and are precipitated out as jarosite or goethite in the presence of calcine and possibly ammonia. Jarosite and goethite are usually disposed of in tailing ponds. Adding zinc dust to the zinc sulfate solution facilitates purification. The purification of leachate leads to precipitation of cadmium, copper, and cobalt as metals. In electrolysis, the purified solution is electrolyzed between lead alloy anodes and aluminum cathodes. The high-purity zinc deposited on aluminum cathodes is stripped off, dried, melted, and cast into SHG zinc ingots (99.99 % zinc). Pyro-metallurgical Smelting The pyro-metallurgical smelting process is based on the reduction of zinc and lead oxides into metal with carbon in an imperial smelting furnace. The sinter, along with pre-heated coke, is charged from the top of the furnace and injected from below with pre-heated air. This ensures that temperature in the center of the furnace remains in the range of 1000-1500 °C. The coke is converted to carbon monoxide, and zinc and lead oxides are reduced to metallic zinc and lead. The liquid lead bullion is collected at the bottom of the furnace along with other metal impurities (copper, silver, and gold). Zinc in vapor form is collected from the top of the furnace along with other gases. Zinc vapor is then condensed into liquid zinc. The lead and cadmium impurities in zinc bullion are removed through a distillation process. The imperial smelting process is an energy-intensive process and produces zinc of lower purity than the electrometallurgical process.
technologyComment of cobalt production (GLO): Cobalt, as a co-product of nickel and copper production, is obtained using a wide range of technologies. The initial life cycle stage covers the mining of the ore through underground or open cast methods. The ore is further processed in beneficiation to produce a concentrate and/or raffinate solution. Metal selection and further concentration is initiated in primary extraction, which may involve calcining, smelting, high pressure leaching, and other processes. The final product is obtained through further refining, which may involve processes such as re-leaching, selective solvent / solution extraction, selective precipitation, electrowinning, and other treatments. Transport is reported separately and consists of only the internal movements of materials / intermediates, and not the movement of final product. Due to its intrinsic value, cobalt has a high recycling rate. However, much of this recycling takes place downstream through the recycling of alloy scrap into new alloy, or goes into the cobalt chemical sector as an intermediate requiring additional refinement. Secondary production, ie production from the recycling of cobalt-containing wastes, is considered in this study in so far as it occurs as part of the participating companies’ production. This was shown to be of very limited significance (less than 1% of cobalt inputs). The secondary materials used for producing cobalt are modelled as entering the system free of environmental burden. technologyComment of natural gas production (CA-AB): Canadian data completed with german data. The uncertainty has been adjusted accordingly. Data used in original data contains no information on technology. technologyComment of natural gas production (DE): Data in environmental report contains no information on technology. technologyComment of natural gas production (RoW): The data describes an average onshore technology for natural gas to 13% out of combined oil gas production. Natural gas is assumed to 20% sour. Leakage in exploitation is estimated at 0.38% and production 0.12%. It is further assumed that about 30% of the produced water is discharged in surface water. Water emissions are differentiated between combined oil and gas production and gas production. technologyComment of natural gas production (RU): The data describes an average onshore technology for natural gas with a share of 4% out of combined oil gas production and 96% from mere natural gas production. Natural gas is assumed to 20% sour. It is assumed that about 30% of the produced water is discharged in surface water. Water emissions are differentiated between combined oil and gas production and gas production. technologyComment of natural gas production (US): US data (NREL) for emissions completed with german data. Emissions from NREL include combined production (petroleumm and gas) and off-shore production. The uncertainty has been adjusted accordingly. Data used in original data contains no information on technology. technologyComment of petroleum refinery operation (CH): Average data for the used technology. technologyComment of primary zinc production from concentrate (RoW): The technological representativeness of this dataset is considered to be high as smelting methods for zinc are consistent in all regions. Refined zinc produced pyro-metallurgically represents less than 5% of global zinc production and less than 2% of this dataset. Electrometallurgical Smelting The main unit processes for electrometallurgical zinc smelting are roasting, leaching, purification, electrolysis, and melting. In both electrometallurgical and pyro-metallurgical zinc production routes, the first step is to remove the sulfur from the concentrate. Roasting or sintering achieves this. The concentrate is heated in a furnace with operating temperature above 900 °C (exothermic, autogenous process) to convert the zinc sulfide to calcine (zinc oxide). Simultaneously, sulfur reacts with oxygen to produce sulfur dioxide, which is subsequently converted to sulfuric acid in acid plants, usually located with zinc-smelting facilities. During the leaching process, the calcine is dissolved in dilute sulfuric acid solution (re-circulated back from the electrolysis cells) to produce aqueous zinc sulfate solution. The iron impurities dissolve as well and are precipitated out as jarosite or goethite in the presence of calcine and possibly ammonia. Jarosite and goethite are usually disposed of in tailing ponds. Adding zinc dust to the zinc sulfate solution facilitates purification. The purification of leachate leads to precipitation of cadmium, copper, and cobalt as metals. In electrolysis, the purified solution is electrolyzed between lead alloy anodes and aluminum cathodes. The high-purity zinc deposited on aluminum cathodes is stripped off, dried, melted, and cast into SHG zinc ingots (99.99 % zinc). Pyro-metallurgical Smelting The pyro-metallurgical smelting process is based on the reduction of zinc and lead oxides into metal with carbon in an imperial smelting furnace. The sinter, along with pre-heated coke, is charged from the top of the furnace and injected from below with pre-heated air. This ensures that temperature in the center of the furnace remains in the range of 1000-1500 °C. The coke is converted to carbon monoxide, and zinc and lead oxides are reduced to metallic zinc and lead. The liquid lead bullion is collected at the bottom of the furnace along with other metal impurities (copper, silver, and gold). Zinc in vapor form is collected from the top of the furnace along with other gases. Zinc vapor is then condensed into liquid zinc. The lead and cadmium impurities in zinc bullion are removed through a distillation process. The imperial smelting process is an energy-intensive process and produces zinc of lower purity than the electrometallurgical process. technologyComment of rare earth oxides production, from rare earth oxide concentrate, 70% REO (CN-SC): This dataset refers to the separation (hydrochloric acid leaching) and refining (metallothermic reduction) process used in order to produce high-purity rare earth oxides (REO) from REO concentrate, 70% beneficiated. ''The concentrate is calcined at temperatures up to 600ºC to oxidize carbonaceous material. Then HCl leaching, alkaline treatment, and second HCl leaching is performed to produce a relatively pure rare earth chloride (95% REO). Hydrochloric acid leaching in Sichuan is capable of separating and recovering the majority of cerium oxide (CeO) in a short process. For this dataset, the entire quantity of Ce (50% cerium dioxide [CeO2]/REO) is assumed to be produced here as CeO2 with a grade of 98% REO. Foreground carbon dioxide CO2 emissions were calculated from chemical reactions of calcining beneficiated ores. Then metallothermic reduction produces the purest rare earth metals (99.99%) and is most common for heavy rare earths. The metals volatilize, are collected, and then condensed at temperatures of 300 to 400°C (Chinese Ministryof Environmental Protection 2009).'' Source: Lee, J. C. K., & Wen, Z. (2017). Rare Earths from Mines to Metals: Comparing Environmental Impacts from China's Main Production Pathways. Journal of Industrial Ecology, 21(5), 1277-1290. doi:10.1111/jiec.12491 technologyComment of scandium oxide production, from rare earth tailings (CN-NM): See general comment. technologyComment of sulfur production, petroleum refinery operation (Europe without Switzerland): The technology level in Europe applied here represents a weighted average of BREF types II (62%), III (29%), IV (9%) refineries; API 35; sulfur content 1.03%. technologyComment of sulfur production, petroleum refinery operation (PE): The technology represents BREF type II refinery; API 25; sulfur content 0.51% technologyComment of sulfur production, petroleum refinery operation (BR): The technology represents BREF type II refinery; API 25; sulfur content 0.57% technologyComment of sulfur production, petroleum refinery operation (ZA): The technology represents a weighted average of BREF types II and III refineries; API 35; sulfur content 0.7% technologyComment of sulfur production, petroleum refinery operation (CO): The technology represents a weighted average of BREF types II and IV refineries; API 35; sulfur content 0.56% technologyComment of sulfur production, petroleum refinery operation (IN): The technology represents a weighted average of BREF types II and IV refineries; API 35; sulfur content 1.39% technologyComment of sulfur production, petroleum refinery operation (RoW): This dataset represents the prevailing technology level in Europe, this is a weighted average of BREF complexity types II (62%), III (29%), IV (9%) refineries (see BREF document, European Commission, 2015); API 35; sulfur content 1.03%. Reference(s): European Commission (2015) Best Available Techniques (BAT) Reference Document (BREF) for the Refining of Mineral Oil and Gas, Industrial Emissions Directive 2010/75/EU Integrated Pollution Prevention and control, accessible online at http://eippcb.jrc.ec.europa.eu/reference/BREF/REF_BREF_2015.pdf, February 2019 technologyComment of synthetic fuel production, from coal, high temperature Fisher-Tropsch operations (ZA): SECUNDA SYNFUEL OPERATIONS: Secunda Synfuels Operations operates the world’s only commercial coal-based synthetic fuels manufacturing facility of its kind, producing synthesis gas (syngas) through coal gasification and natural gas reforming. They make use of their proprietary technology to convert syngas into synthetic fuel components, pipeline gas and chemical feedstock for the downstream production of solvents, polymers, comonomers and other chemicals. Primary internal customers are Sasol Chemicals Operations, Sasol Exploration and Production International and other chemical companies. Carbon is produced for the recarburiser, aluminium, electrode and cathodic production markets. Secunda Synfuels Operations receives coal from five mines in Mpumalanga (see figure attached). After being crushed, the coal is blended to obtain an even quality distribution. Electricity is generated by both steam and gas and used to gasify the coal at a temperature of 1300°C. This produces syngas from which two types of reactor - circulating fluidised bed and Sasol Advanced SynthoTM reactors – produce components for making synthetic fuels as well as a number of downstream chemicals. Gas water and tar oil streams emanating from the gasification process are refined to produce ammonia and various grades of coke respectively. imageUrlTagReplacea79dc0c2-0dda-47ec-94e0-6f076bc8cdb6 SECUNDA CHEMICAL OPERATIONS: The Secunda Chemicals Operations hub forms part of the Southern African Operations and is the consolidation of all the chemical operating facilities in Secunda, along with Site Services activities. The Secunda Chemicals hub produces a diverse range of products that include industrial explosives, fertilisers; polypropylene, ethylene and propylene; solvents (acetone, methyl ethyl ketone (MEK), ethanol, n-Propanol, iso-propanol, SABUTOL-TM, PROPYLOL-TM, mixed C3 and C4 alcohols, mixed C5 and C6 alcohols, High Purity Ethanol, and Ethyl Acetate) as well as the co-monomers, 1-hexene, 1-pentene and 1-octene and detergent alcohol (SafolTM).
technologyComment of cobalt production (GLO): Cobalt, as a co-product of nickel and copper production, is obtained using a wide range of technologies. The initial life cycle stage covers the mining of the ore through underground or open cast methods. The ore is further processed in beneficiation to produce a concentrate and/or raffinate solution. Metal selection and further concentration is initiated in primary extraction, which may involve calcining, smelting, high pressure leaching, and other processes. The final product is obtained through further refining, which may involve processes such as re-leaching, selective solvent / solution extraction, selective precipitation, electrowinning, and other treatments. Transport is reported separately and consists of only the internal movements of materials / intermediates, and not the movement of final product. Due to its intrinsic value, cobalt has a high recycling rate. However, much of this recycling takes place downstream through the recycling of alloy scrap into new alloy, or goes into the cobalt chemical sector as an intermediate requiring additional refinement. Secondary production, ie production from the recycling of cobalt-containing wastes, is considered in this study in so far as it occurs as part of the participating companies’ production. This was shown to be of very limited significance (less than 1% of cobalt inputs). The secondary materials used for producing cobalt are modelled as entering the system free of environmental burden. technologyComment of primary zinc production from concentrate (RoW): The technological representativeness of this dataset is considered to be high as smelting methods for zinc are consistent in all regions. Refined zinc produced pyro-metallurgically represents less than 5% of global zinc production and less than 2% of this dataset. Electrometallurgical Smelting The main unit processes for electrometallurgical zinc smelting are roasting, leaching, purification, electrolysis, and melting. In both electrometallurgical and pyro-metallurgical zinc production routes, the first step is to remove the sulfur from the concentrate. Roasting or sintering achieves this. The concentrate is heated in a furnace with operating temperature above 900 °C (exothermic, autogenous process) to convert the zinc sulfide to calcine (zinc oxide). Simultaneously, sulfur reacts with oxygen to produce sulfur dioxide, which is subsequently converted to sulfuric acid in acid plants, usually located with zinc-smelting facilities. During the leaching process, the calcine is dissolved in dilute sulfuric acid solution (re-circulated back from the electrolysis cells) to produce aqueous zinc sulfate solution. The iron impurities dissolve as well and are precipitated out as jarosite or goethite in the presence of calcine and possibly ammonia. Jarosite and goethite are usually disposed of in tailing ponds. Adding zinc dust to the zinc sulfate solution facilitates purification. The purification of leachate leads to precipitation of cadmium, copper, and cobalt as metals. In electrolysis, the purified solution is electrolyzed between lead alloy anodes and aluminum cathodes. The high-purity zinc deposited on aluminum cathodes is stripped off, dried, melted, and cast into SHG zinc ingots (99.99 % zinc). Pyro-metallurgical Smelting The pyro-metallurgical smelting process is based on the reduction of zinc and lead oxides into metal with carbon in an imperial smelting furnace. The sinter, along with pre-heated coke, is charged from the top of the furnace and injected from below with pre-heated air. This ensures that temperature in the center of the furnace remains in the range of 1000-1500 °C. The coke is converted to carbon monoxide, and zinc and lead oxides are reduced to metallic zinc and lead. The liquid lead bullion is collected at the bottom of the furnace along with other metal impurities (copper, silver, and gold). Zinc in vapor form is collected from the top of the furnace along with other gases. Zinc vapor is then condensed into liquid zinc. The lead and cadmium impurities in zinc bullion are removed through a distillation process. The imperial smelting process is an energy-intensive process and produces zinc of lower purity than the electrometallurgical process. technologyComment of treatment of used Li-ion battery, hydrometallurgical treatment (GLO): Shredder, followed by a chemical treatment in order to separate the various fractions produced technologyComment of treatment of used Li-ion battery, pyrometallurgical treatment (GLO): Crushing of the batteries, followed by a neutralization and a processing step.
technologyComment of aluminium alloy production, AlLi (CA-QC, RoW): No comment present technologyComment of aluminium alloy production, Metallic Matrix Composite (CA-QC, RoW): No comment present technologyComment of cobalt production (GLO): Cobalt, as a co-product of nickel and copper production, is obtained using a wide range of technologies. The initial life cycle stage covers the mining of the ore through underground or open cast methods. The ore is further processed in beneficiation to produce a concentrate and/or raffinate solution. Metal selection and further concentration is initiated in primary extraction, which may involve calcining, smelting, high pressure leaching, and other processes. The final product is obtained through further refining, which may involve processes such as re-leaching, selective solvent / solution extraction, selective precipitation, electrowinning, and other treatments. Transport is reported separately and consists of only the internal movements of materials / intermediates, and not the movement of final product. Due to its intrinsic value, cobalt has a high recycling rate. However, much of this recycling takes place downstream through the recycling of alloy scrap into new alloy, or goes into the cobalt chemical sector as an intermediate requiring additional refinement. Secondary production, ie production from the recycling of cobalt-containing wastes, is considered in this study in so far as it occurs as part of the participating companies’ production. This was shown to be of very limited significance (less than 1% of cobalt inputs). The secondary materials used for producing cobalt are modelled as entering the system free of environmental burden. technologyComment of copper production, cathode, solvent extraction and electrowinning process (GLO): Oxide ores and supergene sulphide ores (i.e. ores not containing iron) can be recovered most easily by hydro-metallurgical techniques, such as SX-EW. The general steps of mining and refining are identical to those of copper mine operation and primary copper production, respectively. The difference lies in that the beneficiation and smelting stages are by-passed and substituted with a leaching stage followed by cementation or electro-winning. technologyComment of electrorefining of copper, anode (GLO): Based on typical current technology. technologyComment of gold mine operation and refining (SE): OPEN PIT MINING: The ore is mined in four steps: drilling, blasting, loading and hauling. In the case of a surface mine, a pattern of holes is drilled in the pit and filled with explosives. The explosives are detonated in order to break up the ground so large shovels or front-end loaders can load it into haul trucks. ORE AND WASTE HAULAGE: The haul trucks transport the ore to various areas for processing. The grade and type of ore determine the processing method used. Higher-grade ores are taken to a mill. Lower grade ores are taken to leach pads. Some ores may be stockpiled for later processing. HEAP LEACHING: The ore is crushed or placed directly on lined leach pads where a dilute cyanide solution is applied to the surface of the heap. The solution percolates down through the ore, where it leaches the gold and flows to a central collection location. The solution is recovered in this closed system. The pregnant leach solution is fed to electrowinning cells and undergoes the same steps as described below from Electro-winning. ORE PROCESSING: Milling: The ore is fed into a series of grinding mills where steel balls grind the ore to a fine slurry or powder. Oxidization and leaching: Some types of ore require further processing before gold is recovered. In this case, the slurry is pressure-oxidized in an autoclave before going to the leaching tanks or a dry powder is fed through a roaster in which it is oxidized using heat before being sent to the leaching tanks as a slurry. The slurry is thickened and runs through a series of leaching tanks. The gold in the slurry adheres to carbon in the tanks. Stripping: The carbon is then moved into a stripping vessel where the gold is removed from the carbon by pumping a hot caustic solution through the carbon. The carbon is later recycled. Electro-winning: The gold-bearing solution is pumped through electro-winning cells or through a zinc precipitation circuit where the gold is recovered from the solution. Smelting: The gold is then melted in a furnace at about 1’064°C and poured into moulds, creating doré bars. Doré bars are unrefined gold bullion bars containing between 60% and 95% gold. References: Newmont (2004) How gold is mined. Newmont. Retrieved from http://www.newmont.com/en/gold/howmined/index.asp technologyComment of platinum group metal mine operation, ore with high palladium content (RU): imageUrlTagReplace6250302f-4c86-4605-a56f-03197a7811f2 technologyComment of platinum group metal, extraction and refinery operations (ZA): The ores from the different ore bodies are processed in concentrators where a PGM concentrate is produced with a tailing by product. The PGM base metal concentrate product from the different concentrators processing the different ores are blended during the smelting phase to balance the sulphur content in the final matte product. Smelter operators also carry out toll smelting from third part concentrators. The smelter product is send to the Base metal refinery where the PGMs are separated from the Base Metals. Precious metal refinery is carried out on PGM concentrate from the Base metal refinery to split the PGMs into individual metal products. Water analyses measurements for Anglo Platinum obtained from literature (Slatter et.al, 2009). Mudd, G., 2010. Platinum group metals: a unique case study in the sustainability of mineral resources, in: The 4th International Platinum Conference, Platinum in Transition “Boom or Bust.” Water share between MC and EC from Mudd (2010). Mudd, G., 2010. Platinum group metals: a unique case study in the sustainability of mineral resources, in: The 4th International Platinum Conference, Platinum in Transition “Boom or Bust.” technologyComment of primary zinc production from concentrate (RoW): The technological representativeness of this dataset is considered to be high as smelting methods for zinc are consistent in all regions. Refined zinc produced pyro-metallurgically represents less than 5% of global zinc production and less than 2% of this dataset. Electrometallurgical Smelting The main unit processes for electrometallurgical zinc smelting are roasting, leaching, purification, electrolysis, and melting. In both electrometallurgical and pyro-metallurgical zinc production routes, the first step is to remove the sulfur from the concentrate. Roasting or sintering achieves this. The concentrate is heated in a furnace with operating temperature above 900 °C (exothermic, autogenous process) to convert the zinc sulfide to calcine (zinc oxide). Simultaneously, sulfur reacts with oxygen to produce sulfur dioxide, which is subsequently converted to sulfuric acid in acid plants, usually located with zinc-smelting facilities. During the leaching process, the calcine is dissolved in dilute sulfuric acid solution (re-circulated back from the electrolysis cells) to produce aqueous zinc sulfate solution. The iron impurities dissolve as well and are precipitated out as jarosite or goethite in the presence of calcine and possibly ammonia. Jarosite and goethite are usually disposed of in tailing ponds. Adding zinc dust to the zinc sulfate solution facilitates purification. The purification of leachate leads to precipitation of cadmium, copper, and cobalt as metals. In electrolysis, the purified solution is electrolyzed between lead alloy anodes and aluminum cathodes. The high-purity zinc deposited on aluminum cathodes is stripped off, dried, melted, and cast into SHG zinc ingots (99.99 % zinc). Pyro-metallurgical Smelting The pyro-metallurgical smelting process is based on the reduction of zinc and lead oxides into metal with carbon in an imperial smelting furnace. The sinter, along with pre-heated coke, is charged from the top of the furnace and injected from below with pre-heated air. This ensures that temperature in the center of the furnace remains in the range of 1000-1500 °C. The coke is converted to carbon monoxide, and zinc and lead oxides are reduced to metallic zinc and lead. The liquid lead bullion is collected at the bottom of the furnace along with other metal impurities (copper, silver, and gold). Zinc in vapor form is collected from the top of the furnace along with other gases. Zinc vapor is then condensed into liquid zinc. The lead and cadmium impurities in zinc bullion are removed through a distillation process. The imperial smelting process is an energy-intensive process and produces zinc of lower purity than the electrometallurgical process. technologyComment of treatment of copper cake (GLO): 'The ore is pre-treated, reduced and refined according to the country specific mix of process alternatives: reverberatory furnace 23.7%; flash smelting furnaces 60.7%; other 6.2%.; SX-EW 9.4%. An overall abatement for sulphur dioxide of 45.4% was estimated.' as cited in original dataset. technologyComment of treatment of copper scrap by electrolytic refining (RoW): In three different stages different types of copper scrap and 10% of the feed of blister copper are refined to copper cathodes. Waste water is led to a communal treatment plant. technologyComment of treatment of copper scrap by electrolytic refining (RER): Secondary copper consists of various types of scrap. Prompt scrap is directly reused in foundries and is not further processed. Old scrap has to be treated in a secondary copper smelter, where a variety of metal values are recuperated. Depending on the chemical composition, the raw materials of a secondary copper smelter are processed in different types of furnaces, including: - blast furnaces (up to 30% of Cu in the average charge), - converters (about 75% Cu), and - anode furnaces (about 95% Cu). A scheme of the process considered is given in Fig 1. The blast furnace metal (“black copper”) is treated in a converter; then, the converter metal is refined in an anode furnace. In each step additional raw material with corresponding copper content is added. In the blast furnace, a mixture of raw materials, iron scrap, limestone and sand as well as coke is charged at the top. Air that can be enriched with oxygen is blown through the tuyeres. The coke is burnt and the charge materials are smelted under reducing conditions. Black copper and slag are discharged from tapholes. The converters used in primary copper smelting, working on mattes containing iron sulphide, generate surplus heat and additions of scrap copper are often used to control the temperature. The converter provides a convenient and cheap form of scrap treatment, but often with only moderately efficient gas cleaning. Alternatively, hydrometallurgical treatment of scrap, using ammonia leaching, yields to solutions which can be reduced by hydrogen to obtain copper powder. Alternatively, these solutions can be treated by solvent extraction to produce feed to a copper-winning cell. Converter copper is charged together with copper raw materials in anode furnace operation. For smelting the charge, oil or coal dust is used, mainly in reverberatory furnaces. After smelting, air is blown on the bath to oxidise the remaining impurities. Leaded brasses, containing as much as 3% of lead, are widely used in various applications and recycling of their scrap waste is an important activity. Such scrap contains usually much swarf and turnings coated with lubricant and cutting oils. Copper-containing cables and motors contain plastic or rubber insulants, varnishes, and lacquers. In such cases, scrap needs pre-treatment to remove these non-metallic materials. The smaller sizes of scrap can be pre-treated thermally in a rotary kiln provided with an after-burner to consume smoke and oil vapours (so-called Intal process). Emissions and waste: Elevated levels of halogenated organic compounds may arise, such as TCDD. Slags are usually used in construction. Waste water is led to a communal treatment plant. References: EEA, 1999. imageUrlTagReplacef2b602ec-dc47-48e3-88a7-ab8ec727bd33 technologyComment of treatment of metal part of electronics scrap, in copper, anode, by electrolytic refining (SE, RoW): Production of cathode copper by electrolytic refining. technologyComment of treatment of non-Fe-Co-metals, from used Li-ion battery, hydrometallurgical processing (GLO): The technique SX-EW is used mainly for oxide ores and supergene sulphide ores (i.e. ores not containing iron). It is assumed to be used for the treatment of the non-Fe-Co-metals fraction. The process includes a leaching stage followed by cementation or electro-winning. A general description of the process steps is given below. In the dump leaching step, copper is recovered from large quantities (millions of tonnes) of strip oxide ores with a very low grade. Dilute sulphuric acid is trickled through the material. Once the process starts it continues naturally if water and air are circulated through the heap. The time required is typically measured in years. Sulphur dioxide is emitted during such operations. Soluble copper is then recovered from drainage tunnels and ponds. Copper recovery rates vary from 30% to 70%. Cconsiderable amounts of sulphuric acid and leaching agents emit into water and air. No figures are currently available on the dimension of such emissions. After the solvent-solvent extraction, considerable amounts of leaching residues remain, which consist of undissolved minerals and the remainders of leaching chemicals. In the solution cleaning step occur precipitation of impurities and filtration or selective enrichment of copper by solvent extraction or ion exchange. The solvent extraction process comprises two steps: selective extraction of copper from an aqueous leach solution into an organic phase (extraction circuit) and the re-extraction or stripping of the copper into dilute sulphuric acid to give a solution suitable for electro winning (stripping circuit). In the separation step occurs precipitation of copper metal or copper compounds such as Cu2O, CuS, CuCl, CuI, CuCN, or CuSO4 • 5 H2O (crystallisation) Waste: Like in the pyrometallurgical step, considerable quantities of solid residuals are generated, which are mostly recycled within the process or sent to other specialists to recover any precious metals. Final residues generally comprise hydroxide filter cakes (iron hydroxide, 60% water, cat I industrial waste). technologyComment of treatment of non-Fe-Co-metals, from used Li-ion battery, pyrometallurgical processing (GLO): Based on technology that treats anode slime by pressure leaching and top blown rotary converter. technologyComment of treatment of used cable (GLO): Shredder, followed by a modern grinding machine with current separation technology
technologyComment of cobalt production (GLO): Cobalt, as a co-product of nickel and copper production, is obtained using a wide range of technologies. The initial life cycle stage covers the mining of the ore through underground or open cast methods. The ore is further processed in beneficiation to produce a concentrate and/or raffinate solution. Metal selection and further concentration is initiated in primary extraction, which may involve calcining, smelting, high pressure leaching, and other processes. The final product is obtained through further refining, which may involve processes such as re-leaching, selective solvent / solution extraction, selective precipitation, electrowinning, and other treatments. Transport is reported separately and consists of only the internal movements of materials / intermediates, and not the movement of final product. Due to its intrinsic value, cobalt has a high recycling rate. However, much of this recycling takes place downstream through the recycling of alloy scrap into new alloy, or goes into the cobalt chemical sector as an intermediate requiring additional refinement. Secondary production, ie production from the recycling of cobalt-containing wastes, is considered in this study in so far as it occurs as part of the participating companies’ production. This was shown to be of very limited significance (less than 1% of cobalt inputs). The secondary materials used for producing cobalt are modelled as entering the system free of environmental burden. technologyComment of copper mine operation and beneficiation, sulfide ore (AU, CA, CL, CN, ID, KZ, RU, US, ZM, RoW): Based on typical current technology. Mining is done 70% open pit and 30% underground, followed by joint beneficiation of copper and molybdenite trough flotation, where considerable amounts of agents are added. Overburden is disposed separate to sulfidic tailings near the mining site. No dewatering (or other pre-treatment) of the tailings of is assumed as this is considered a treatment activity that occurs only at selective sites and is therefore modelled separately. technologyComment of gold-silver mine operation and beneficiation (CA-QC): The ore is mined in an underground mine and transported by trucks to the mill for further processing. The ore is then fed into a series of grinding mills where steel balls grind the ore. Then follows the steps of flotation of copper and zinc, concentrate handling, cyanide destruction and backfilling of the tailings, refining of gold by electro-winning and melting in furnace to produce the gold and silver ingots. 20% of the tailings produce are sent underground to be used as backfill; sulfidic tailing is managed on site in tailings ponds. technologyComment of molybdenite mine operation (GLO): imageUrlTagReplacead2d66f4-3a0d-4ae6-a5ca-e63fd821a4fc Mining. Sulphidic copper ores are mined only 30% underground, the major part is mined in large open cut operations. The ore mined in 1900 in the U.S. had a high content of 3.4% and was mined entirely underground. Open pit mining permits the use of very large equipment. Resulting economies of scale enable the exploitation of lower grade disseminated (porphyry) ores – the ores now mainly mined. The major emissions are due to mineral born pollutants in the effluents. Open cut mining generates large quantities of dust, which contains elevated contents of metals and sulphur. Rain percolates through overburden and accounts to metal emissions to groundwater. Overburden is deposed close to the mine. No overburden is refilled. imageUrlTagReplace47e24476-56f3-4016-9151-88908e3e0072 Beneficiation. After mining, the ore is first ground. In a next step it is subjected to gravity concentration to separate the metal-bearing particles from the unwanted minerals. After this first concentration step, flotation is carried out to remove the gangue from the sulphidic minerals. For neutralisation lime is added. In the flotation several organic chemicals ( such as collectors (xanthate or aerofloat) and frothing reagent (eg. Methyl Isobutyl Carbinol)) are used as collector, frother, activator, depressor and flocculant. Sometimes cyanide is used as depressant for pyrite. Tailings usually are led to tailings heaps or ponds. As a result, copper concentrates containing around 30% Cu are produced. Molybdenite concentrate are further ground and purified. It leaves the process as co-product with a concentration of 90 – 95 % Molybdenum disulphide. The concentrated ore is fed to the metallurgy, which is assumed to be on-site. Ore handling and processing produce large amounts of dust, containing PM10 and several metals from the ore itself. Flotation produces effluents containing several organic agents used. Some of these chemicals evaporate and account for VOC emissions to air. Namely xanthates decompose hydrolytically to release carbon disulphide. Tailings effluent contains additional sulphuric acid from acid rock drainage. Tailings are deposed as piles and in ponds. In the sulphidic tailings occurs acid rock drainage (ARD) over a long period of time. Reserves and resources: Molybdenum and Copper are coexisting in porphyry deposits of the copper-molybdenum type, as molybdenite (MoS2) and chalcopyrite (CuFeS2). About half of the world-wide produced molybdenum is a co-product of the primary copper industry while for another substantial part copper is the co-product. Hence almost all of the molybdenum is produced in a process similar to the copper primary production. Molybdenum secondary production – mainly from spent petroleum catalysts – is not remarkable, and no secondary production is considered in this study. It's estimated that 30% of the molybdenum is re-used in the form of the molybdenum content steel alloys which are recycled to the foundries. Secondary production of copper from scrap plays an important role. The resources of primary copper are limited, a continuous depletion within 60 years is estimated. Land-based resources of copper are estimated to be 1.6 billion tons , and resources in deep-sea nodules are estimated to be 700 million tons. A detailed overview over the global refinery production and a statistic on US use and production of copper is available in the online version of the USGS “Mineral Commodity Summary”. The world-wide mine estimated reserves by country are listed in Tab. 1. Exploitable reserves of recoverable copper were estimated at about 100 million tons in 1935; new discoveries raised this to 212 million tons in 1960. Reserves grew again sharply to 340 million metric tons (MMT) in 1984, but since then they have declined slowly to 321 MMT in 1990 and 310 MMT in 1994. Estimates vary according to prices and assumptions. Total potential resources have increased somewhat over the same period, from 500 MMT to around 590 MMT. As a matter of interest, cumulative global production of copper between 1970 and 1996 was 216 MMT. With the actual mine production of around 13.5 MMT/a, the reserves would last 36 years and the reserve base 70 years. Reserves of molybdenite in the market economy countries have been estimated in a survey evaluating identified ore bodies, i.e., those which have been explored as well as those which have been exploited. The results indicate the following amounts of recoverable molybdenum: United States, 4100 kt; Chile, 1770 kt; Canada, 928 kt; Mexico, 306 kt; Peru, 288 kt; other countries, 356 kt. Ore bodies producing primarily molybdenum contain 55 % of the reserves identified; only 29 % of these ore bodies were being exploited at the time of the survey (January 1985). Operations producing molybdenum as a byproduct contained the remaining 45 % of reserves and 67 % of them were producing molybdenite. The estimated total recoverable molybdenum from primary and byproduct reserves is listed in Tab. 2. References: Krauss et al. (1999), Sebenik et al. (1997), USGS (2003), Ayres et al. (2002). technologyComment of primary zinc production from concentrate (RoW): The technological representativeness of this dataset is considered to be high as smelting methods for zinc are consistent in all regions. Refined zinc produced pyro-metallurgically represents less than 5% of global zinc production and less than 2% of this dataset. Electrometallurgical Smelting The main unit processes for electrometallurgical zinc smelting are roasting, leaching, purification, electrolysis, and melting. In both electrometallurgical and pyro-metallurgical zinc production routes, the first step is to remove the sulfur from the concentrate. Roasting or sintering achieves this. The concentrate is heated in a furnace with operating temperature above 900 °C (exothermic, autogenous process) to convert the zinc sulfide to calcine (zinc oxide). Simultaneously, sulfur reacts with oxygen to produce sulfur dioxide, which is subsequently converted to sulfuric acid in acid plants, usually located with zinc-smelting facilities. During the leaching process, the calcine is dissolved in dilute sulfuric acid solution (re-circulated back from the electrolysis cells) to produce aqueous zinc sulfate solution. The iron impurities dissolve as well and are precipitated out as jarosite or goethite in the presence of calcine and possibly ammonia. Jarosite and goethite are usually disposed of in tailing ponds. Adding zinc dust to the zinc sulfate solution facilitates purification. The purification of leachate leads to precipitation of cadmium, copper, and cobalt as metals. In electrolysis, the purified solution is electrolyzed between lead alloy anodes and aluminum cathodes. The high-purity zinc deposited on aluminum cathodes is stripped off, dried, melted, and cast into SHG zinc ingots (99.99 % zinc). Pyro-metallurgical Smelting The pyro-metallurgical smelting process is based on the reduction of zinc and lead oxides into metal with carbon in an imperial smelting furnace. The sinter, along with pre-heated coke, is charged from the top of the furnace and injected from below with pre-heated air. This ensures that temperature in the center of the furnace remains in the range of 1000-1500 °C. The coke is converted to carbon monoxide, and zinc and lead oxides are reduced to metallic zinc and lead. The liquid lead bullion is collected at the bottom of the furnace along with other metal impurities (copper, silver, and gold). Zinc in vapor form is collected from the top of the furnace along with other gases. Zinc vapor is then condensed into liquid zinc. The lead and cadmium impurities in zinc bullion are removed through a distillation process. The imperial smelting process is an energy-intensive process and produces zinc of lower purity than the electrometallurgical process. technologyComment of smelting and refining of nickel concentrate, 16% Ni (GLO): Extrapolated from a typical technology for smelting and refining of nickel ore. MINING: 95% of sulphidic nickel ores are mined underground in depths between 200m and 1800m, the ore is transferred to the beneficiation. Widening of the tunnels is mainly done by blasting. The overburden – material, which does not contain PGM-bearing ore – is deposed off-site and is partially refilled into the tunnels. Emissions: The major emissions are due to mineral born pollutants in the effluents. The underground mining operations generate roughly 80 % of the dust emissions from open pit operations, since the major dust sources do not take place underground. Rain percolate through overburden and accounts to metal emissions to groundwater. Waste: Overburden is deposed close to the mine. Acid rock drainage occurs over a long period of time. BENEFICIATION: After mining, the ore is first ground. In a next step it is subjected to gravity concentration to separate the metallic particles from the PGM-bearing minerals. After this first concentration step, flotation is carried out to remove the gangue from the sulphidic minerals. For neutralisation lime is added. In the flotation several organic chemicals are used as collector, frother, activator, depressor and flocculant. Sometimes cyanide is used as depressant for pyrite. Tailings usually are led to tailing heaps or ponds. As a result, nickel concentrates containing 7 - 25% Ni are produced. Emissions: Ore handling and processing produce large amounts of dust, containing PM10 and several metals from the ore itself. Flotation produce effluents containing several organic agents used. Some of these chemicals evaporate and account for VOC emissions to air. Namely xanthates decompose hydrolytically to release carbon disulphide. Tailings effluent contains additional sulphuric acid from acid rock drainage. Waste: Tailings are deposed as piles and in ponds. Acid rock drainage occurs over a long period of time. METALLURGY AND REFINING: There are many different process possibilities to win the metal. The chosen process depends on the composition of the ore, the local costs of energy carrier and the local legislation. Basically two different types can be distinguished: the hydrometallurgical and the pyrometallurgical process, which paired up with the refining processes, make up five major production routes (See Tab.1). All this routes are covered, aggregated according to their market share in 1994. imageUrlTagReplace00ebef53-ae97-400f-a602-7405e896cb76 Pyrometallurgy. The pyrometallurgical treatment of nickel concentrates includes three types of unit operation: roasting, smelting, and converting. In the roasting step sulphur is driven off as sulphur dioxide and part of the iron is oxidised. In smelting, the roaster product is melted with a siliceous flux which combines with the oxidised iron to produce two immiscible phases, a liquid silicate slag which can be discarded, and a solution of molten sulphides which contains the metal values. In the converting operation on the sulphide melt, more sulphur is driven off as sulphur dioxide, and the remaining iron is oxidised and fluxed for removal as silicate slag, leaving a high-grade nickel – copper sulphide matte. In several modern operations the roasting step has been eliminated, and the nickel sulphide concentrate is treated directly in the smelter. Hydrometallurgy: Several hydrometallurgical processes are in commercial operation for the treatment of nickel – copper mattes to produce separate nickel and copper products. In addition, the hydrometal-lurgical process developed by Sherritt Gordon in the early 1950s for the direct treatment of nickel sulphide concentrates, as an alternative to smelting, is still commercially viable and competitive, despite very significant improvements in the economics and energy efficiency of nickel smelting technology. In a typical hydrometallurgical process, the concentrate or matte is first leached in a sulphate or chloride solution to dissolve nickel, cobalt, and some of the copper, while the sulphide is oxidised to insoluble elemental sulphur or soluble sulphate. Frequently, leaching is carried out in a two-stage countercurrent system so that the matte can be used to partially purify the solution, for example, by precipitating copper by cementation. In this way a nickel – copper matte can be treated in a two-stage leach process to produce a copper-free nickel sulphate or nickel chloride solution, and a leach residue enriched in copper. Refining: In many applications, high-purity nickel is essential and Class I nickel products, which include electrolytic cathode, carbonyl powder, and hydrogen-reduced powder, are made by a variety of refining processes. The carbonyl refining process uses the property of nickel to form volatile nickel-carbonyl compounds from which elemental nickel subsides to form granules. Electrolytic nickel refineries treat cast raw nickel anodes in a electrolyte. Under current the anode dissolves and pure nickel deposits on the cathode. This electrorefining process is obsolete because of high energy demand and the necessity of building the crude nickel anode by reduction with coke. It is still practised in Russia. Most refineries recover electrolytic nickel by direct electrowinning from purified solutions produced by the leaching of nickel or nickel – copper mattes. Some companies recover refined nickel powder from purified ammoniacal solution by reduction with hydrogen. Emissions: In all of the metallurgical steps, sulphur dioxide is emitted to air. Recovery of sulphur dioxide is only economic for high concentrated off-gas. Given that In the beneficiation step, considerable amounts of lime are added to the ore for pH-stabilisation, lime forms later flux in the metallurgical step, and decomposes into CO2 to form calcite. Dust carry over from the roasting, smelting and converting processes. Particulate emissions to the air consist of metals and thus are often returned to the leaching process after treatment. Chlorine is used in some leaching stages and is produced during the subsequent electrolysis of chloride solution. The chlorine evolved is collected and re-used in the leach stage. The presence of chlorine in wastewater can lead to the formation of organic chlorine compounds (AOX) if solvents etc. are also present in a mixed wastewater. VOCs can be emitted from the solvent extraction stages. A variety of solvents are used an they contain various complexing agents to form complexes with the desired metal that are soluble in the organic layer. Metals and their compounds and substances in suspension are the main pollutants emitted to water. The metals concerned are Cu, Ni, Co, As and Cr. Other significant substances are chlorides and sulphates. Wastewater from wet gas cleaning (if used) of the different metallurgical stages are the most important sources. The leaching stages are usually operated on a closed circuit and drainage systems, and are therefore regarded as minor sources. In the refining step, the combustion of sulphur leads to emissions of SO2. Nitrogen oxides are produced in significant amounts during acid digestion using nitric acid. Chlorine and HCl can be formed during a number of digestion, electrolytic and purification processes. Chlorine is used extensively in the Miller process and in the dissolution stages using hydrochloric acid and chlorine mixtrues respectively. Dust and metals are generally emitted from incinerators and furnaces. VOC can be emitted from solvent extraction processes, while organic compounds, namely dioxins, can be emitted from smelting stages resulting from the poor combustion of oil and plastic in the feed material. All these emissions are subject to abatement technologies and controlling. Large quantities of effluents contain amounts of metals and organic substances. Waste: Regarding the metallurgical step, several co-products, residues and wastes, which are listed in the European Waste Catalogue, are generated. Some of the process specific residues can be reused or recovered in preliminary process steps (e. g. dross, filter dust) or construction (e. g. cleaned slag). Residues also arise from the treatment of liquid effluents, the main residue being gypsum waste and metal hydroxides from the wastewater neutralisation plant. These residuals have to be disposed, usually in lined ponds. In the refining step, quantities of solid residuals are also generated, which are mostly recycled within the process or sent to other specialists to recover any precious metals. Final residues generally comprise hydroxide filter cakes (ironhydroxide, 60% water, cat I industrial waste). References: Kerfoot D. G. E. (1997) Nickel. In: Ullmann's encyclopedia of industrial chemis-try (ed. Anonymous). 5th edition on CD-ROM Edition. Wiley & Sons, London. technologyComment of zinc mine operation (GLO): The technological representativeness of this dataset is considered to be high as mining and concentration methods for zinc are consistent in all regions. Mining The mining of zinc ore includes underground and open cast mining processes. Within the global zinc industry, about 80% of zinc ore comes from underground mines and 20% from open pit or combination mines. - Underground Mining: Access is via vertical shafts or inclined roadways. There are usually two access routes (one for mining personnel and materials, and one for the ore) for safety and for ease of ventilation (fresh air comes in one and is then exhausted out of the other). These are permanent structures and therefore require strong roof supports (often including "bolts" into the rock to tie the layers together for strength). Once at the correct depth has been reached, horizontal tunnels are driven to reach the ore deposit. These are often temporary, so the support requirements are less substantial. Transport for personnel and materials can be by train, truck or conveyor belts. The largest share of the consumed fuels is diesel followed by electricity. Other major inputs include explosives and water. - Open Pit Mining: Hard-rock surface mining usually includes drilling, blasting, or a combination of both processes, and then lifting of the broken ore either into trucks or onto conveyors for transportation to the processing plant. This lifting is usually by excavator (electric or hydraulic; with shovel or backhoe configuration) or front-end loader. Benefication (Comminution and Flotation) Zinc ore is milled and mixed with water to recover a fine concentrate by gravity and elutriation techniques, creating a slurry. The separation process of the metal from the slurry is realized through the addition of various floatation chemicals.
The BAT reference document (BREF) entitled 'Non-Ferrous Metals Industries' forms part of a series presenting the results of an exchange of information between EU Member States, the industries concerned, non-governmental organisations promoting environmental protection, and the Commission, to draw up, review and, where necessary, update BAT reference documents as required by Article 13(1) of the Directive 2010/75/EU on industrial emissions. This document is published by the European Commission pursuant to Article 13(6) of the Directive. This BREF for 'Non-Ferrous Metals Industries' concerns the activities specified in Sections 2 and 6.8 of Annex I to Directive 2010/75/EU, namely: - 2.1: Metal ore (including sulphide ore) roasting or sintering; - 2.5: Processing of non-ferrous metals: (a) production of non-ferrous crude metals from ore, concentrates or secondary raw materials by metallurgical, chemical or electrolytic processes; (b) melting, including the alloyage, of non-ferrous metals, including recovered products and operation of non-ferrous metal foundries, with a melting capacity exceeding 4 tonnes per day for lead and cadmium or 20 tonnes per day for all other metals; - 6.8: Production of carbon (hard-burnt coal) or electrographite by means of incineration or graphitisation. This document also covers: - the production of zinc oxide from fumes during the production of other metals; - the production of nickel compounds from liquors during the production of a metal; - the production of silicon-calcium (CaSi) and silicon (Si) in the same furnace as the production of ferro-silicon; - the production of aluminium oxide from bauxite prior to the production of primary aluminium, where this is an integral part of the production of the metal; - the recycling of aluminium salt slag. Important issues for the implementation of Directive 2010/75/EU in the non-ferrous metals industries are the emissions to air of dust, metals, organic compounds (which can result in the formation of PCDD/F) and sulphur dioxide; diffuse air emissions; emissions to water of metals (e.g. Hg, Cd, Cu, Pb, Zn); resource efficiency; and the prevention of emissions to soil and groundwater. This BREF contains 12 chapters. Chapters 1 and 2 provide general information on the non-ferrous metals industry and on the common industrial processes and techniques used within the whole sector. Chapters 3, 4, 5, 6, 7, 8, 9 and 10 correspond to the following specific production sectors: copper, aluminium, lead and/or tin, zinc and/or cadmium, precious metals, ferro-alloys, nickel and/or cobalt, and carbon and graphite. For each specific production sector, these eight chapters provide information and data concerning the applied processes and techniques; the environmental performance of installations in terms of current emissions, consumption of raw materials, water and energy, and generation of waste; the techniques to prevent or, where this is not practicable, to reduce the environmental impact of operating installations in these sectors that were considered in determining the BAT; and the emerging techniques as defined in Article 3(14) of the Directive. Chapter 11 presents the BAT conclusions as defined in Article 3(12) of the Directive. Chapter 12 is dedicated to concluding remarks and recommendations for future work. Quelle: BAT-Merkblatt JRC 107041
Das Projekt "Hot gas-cleaning" wird vom Umweltbundesamt gefördert und von DMT-Gesellschaft für Forschung und Prüfung mbH durchgeführt. General Information: Descriptions of the individual parts of the project are given below. Removal of trace elements in hot gas cleaning systems (CSIC). Study of the capture of trace elements by a range of different sorbents - mainly metal mixed oxides, clay materials and alkaline-earth carbonates but also some alumina and siliceous materials - in two laboratory scale reactors (a fixed bed and a fluidised bed) at temperatures between 550 and 750 degree C. Different compositions of the simulated coal gas stream will also be tested. Different sorbents, temperatures and stream gas composition will be studied during each of three periods of six months in each of the three years of the programme. Hot H2S Removal by using waste products as solvents (TGI). Testing of red mud (a residue from aluminium manufacture) and electric arc furnace dust (a residue from steel making) as sorbents for hot dry desulphurisation of coat derived fuel gas. These materials have been chosen as containing potential sorbents including calcium, iron, zinc and manganese oxides. Tests will be carried out in a laboratory-scale pressurised reactor. Use of carbon materials and membranes for hot gas clean up (DMT). Study of the potential use of carbon materials for removing trace metals and sulphur compounds from hot gasification gases (also potentially the separation of light gases such as hydrogen), taking advantage of the stability of carbon at high temperature and in corrosive atmospheres. A bed of carbon (or, where appropriate, another material) alone or in combination with a carbon filtering membrane installed in a laboratory gas circuit will be used: - to study the effect on composition of passing gas from a gasifier through a bed of activated carbon or a carbon molecular sieve at various temperatures, pressures and flow rates. - to repeat the studies as above with a filtering membrane made from carbon added. - to study the combination of sorption/filtration and catalytically active materials (i.e. using catalysts for the CO shift and for hydrogenation). The use of other compounds such as zeolitic membranes or granular beds will also be considered and the advantages of using combined gas clean up systems will be reviewed in the light of the data obtained. Development of improved stable catalysts and trace elements capture for hot gas cleaning in advanced power generation (CRE Group). Studies will be carried out on existing equipment to improve and assess catalysts based on iron oxide on silica and titania with mixed metal oxides to remove ammonia, hydrogen cyanide, hydrogen chloride, arsine, hydrogen sulphide and carbonyl sulphide. Selected catalysts will be tested at pressures up to 20 bar and temperatures in the range 500 - 800 degree C using simulated atmospheres. ... Prime Contractor: Deutsche Montan Technologie, Gesellschaft für Forschung und Prüfung mbH (DMT); Essen; Germany.
Das Projekt "Alkalische Laugung von Blei/Zinn/Zinkflugstaeuben" wird vom Umweltbundesamt gefördert und von Technische Hochschule Aachen, IME, Metallurgische Prozesstechnik und Metallrecycling durchgeführt. Fuer die Aufarbeitung von Pb/Sn/Zn-Flugstaeuben, die bei der Stahlherstellung aus Schrotten sowie bei der Gewinnung von NE-Metallen entstehen, soll ein generelles Schema hydrometallurgischer Verfahren entwickelt werden. Ausgehend von der jeweiligen Zusammensetzung der Flugstaeube (vorwiegend Zink- und andere Metalloxide) wurden folgende Loesungsalternativen untersucht: 1) Laugung mit Wasser und schwach alkalischer Loesung zur Entfernung der Cl- und SO4-Gehalte sowie auch von Alkali, eventuell von Blei. 2) Laugung mit starker Natronlauge zur Loesung von Zink und Blei. 3) Laugung mit Schwefelsaeure zur Loesung von Zink. 4) Reinigung der Laugenloesungen durch Zementation mit Zn-Pulver. 5) Absetzverhalten und Filtrationsverhalten der Trueben ohne und mit Flockungshilfsmitteln sowie Filtration. Dabei wurden folgende Ergebnisse erzielt. 1) Bei der Wasserlaugung erreicht man eine maximale Entfernung von 90 Prozent Cl und Alkali und etwa 4 Prozent SO4 nach 60 Min. Laugung bei 90 Grad C, so dass auf diese Weise Chlorid und Alkali selektiv abgetrennt werden koennen. 2) Der Zusatz von NaOH zum Wasser erhoeht nicht nur die Loeslichkeit des Cl auf 95 Prozent sondern auch die des SO4 auf bis zu 95 Prozent und die des Pb zu etwa 80 Prozent. Nach einer Wasserlaugung kann so auch Sulfat selektiv abgetrennt werden. 3) Bei der stark alkalischen Laugung erreicht man unter optimalen Bedingungen eine Aufloesung von fast 100 Prozent des Bleis und 90 Prozent des Zinks. Kupfer und Zinn zeigen dagegen eine nur niedrige Loeslichkeit von max. 40 Prozent Cu und max. 10 Prozent Sn. 4) Bei der sauren Laugung unter optimalen Bedingungen (200 g/l H2SO4 und 150 g/l Feststoff) gehen...
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