Cominco process

The Sherritt-Cominco process was developed as an alternative to smelting of sulfide concentrates. The key feature of the Sherritt-Cominco process is the removal of iron before the leaching of copper. The concentrate is thermally activated and leached with sulfuric acid to dissolve iron. Iron is precipitated as jarosite. The leach residue is pressure leached with oxygen in acid solution to convert copper sulfides to copper sulfates. The solution is purified by the coprecipitation of Te, As, Bi, Sb, Pb, and Se with Fe2C>3. The electrolyte contains 30 g L 1 Cu and 140 g L 1 sulfuric... 

FIGURE 9.2-9 Cominco process for ihe direct pressure leaching of zinc sulfide concentrates. (Reproduced from Parker el al.36)... 

The ICI process is an example of neutralization at atmospheric pressure. Nitric acid feed is preheated by part of the vapors produced in the neutralizer and is then split into two streams. Recycled, undersized product is dissolved in one stream, conditioning material in the other. The recombined streams are added to a two stage neutralizer along with ammonia and recirculated solution to give 87 to 89% ammonium nitrate feed for evaporation. The C I—Girdler-Cominco process is similar in principle the Pintsch-Bamag (23) process uses a two-stage neutralizer without recirculation. 

Operating data for four absorption systems of plants utilizing the Cominco process are presented in TaUe 7-25. Obsraved sulfor dioxide removal efficiencies vary fonn 8S to 97%. The degree of sulfur dioxide removal attainable in a system of this type is obviously d en-doit upon a large nuniba of variables. Chief among these are... 

Table 7-25 Cominco Process Absorber Operattng Data ...

Development work on this process was conducted by TVA at its Colbert Power Plant (Breed and Hollinden, 1974 TVA, 1974). The concept is closely related to the Cominco process in that the SO2 is absorbed in an ammonium sulfite solution and then liberated by acidulation of the solution. It differs, however, in the technique employed for acidulation. 

Electrolytic Eefming. Electrolytic refining (26,27), used by Cominco Ltd. (Trad, B.C., Canada) and Cerro de Pasco Corp. (La Oroya, Pern), as weU as by several refineries in Europe and Japan, removes impurities in one step as slimes. The impurities must then be separated and purified. Before the development of the Betterton-KroU process, electrolytic refining was the only practical method of reducing bismuth to the required concentrations. 

A pressure leaching system to handle copper sulfide called the Sherritt-Cominco (SC) copper process was developed by these two Canadian firms. Pilot-plant testing was completed in 1976 (29), but commercial appHcation of this technology has not been achieved. 

Thus, roasting is avoided. The process, especially amenable to high iron and copper concentrates, has been installed by Cominco, Ltd. (44) at Trad, B.C., Canada, and will be installed at the Kidd Creek Mines, Ltd., plant at Timmins, Ontario. 

Cominco [Consolidated Mining Smelting Company] A process for absorbing sulfur dioxide from smelting operations. The sulfur dioxide is absorbed in an aqueous solution of ammonium sulfite regeneration is by acidification with sulfuric acid. The ammonium sulfate byproduct is sold. Operated at the Cominco smelter at Trail, Canada, and at other smelters and sulfuric acid plants in the United States. Licensed by the Olin Mathieson Corporation. The name has been applied also to a lead extraction process. 

Sherritt-Cominco A process for extracting copper from chalcopyrite, CuFeS2. The ore is reduced with hydrogen, the iron leached out with sulfuric acid, the residual Cu5FeS4 dissolved in concentrated sulfuric acid, and the copper isolated by electrowinning or hydrogen reduction. Pilot testing was complete in 1976. 

Methods for making higher strength P205 acid have been known for a long time. The basic hemihydrate-dihydrate process shown in the Hydro Fertilizer flowsheet, Fig. 23.12, is similar to the initial process attempted in 1931 at the Cominco plant at Trail, BC. The hemihydrate-dihydrate process failed there, mostly because of inadequate filters, but the Dorr dihydrate process did emerge successfully. 

Leyshon, D. W The Origin of the Modern Dihydrate Phosphoric Acid Process—Cominco 1931, A.I.Ch.E., Orlando, FL, 1990. 

HydroZinc A biological process for leaching zinc from heaps of zinc sulfide ore. Naturally occurring bacteria attack the ore, and the leachate is then neutralized and extracted with a solvent. The metal is produced from this liquor by electrowinning. The process was developed by Teck Cominco in British Columbia and piloted between 2000 and 2002. 

In 2003, the world zinc production was 9 880000 tons [55]. The most important zinc production process is the electrolytic or roast-leach-electrowinning (RLE) process. This was first used in 1916 by Anaconda and Cominco. The industrial processes of zinc production use zinc oxides as raw materials. The most important natural raw material is zinc sulfide, and, therefore, it needs to be roasted and converted to oxide. The main problem in leaching and liquor purification is separation of zinc and iron. As dissolution of iron cannot be avoided, it must be precipitated from the zinc sulfate solution. Impurities still present after the iron precipitation stage can lead to lower current efficiency and impurities in the zinc cathode. Therefore, the solution is further purified by cementation with zinc powder. 

H. L. Lizama, J. R. Harlamovs, S. Belanger, The Teck Cominco Hydrozinc process in Hydrometallurgy 2003 - Fifth International Conference in Honor of Professor Ian Ritchie, Vancouver, (Eds. C. A. Young, A. M. Alfantazi, C. G. Anderson et al.),TMS (TheMiner-als, Metals Materials Society), Vancouver, Canada, 2003, pp. 1503-1516. 

When liquid air distillation is used as the source of nitrogen, the hydrogen also required for ammonia synthesis is obtained from a variety of sources. Some is obtained as the coproduct from the electrolytic production of chlorine and caustic soda (Chap. 8), some from refinery sources as a by-product of cracking processes or olefin synthesis, some from the water-gas reaction, and some is produced specifically for the purpose by the electrolysis of alkaline water (e.g., by Cominco, Trail, Eq. 11.14). 

The Sherritt-Cominco hydrometallurgical process makes the method applicable to chalcopyrite (CuFeSi) ores [49]. After thermal rearrangement and reduction of the concentrate with hydrogen it is leached first with sulfuric acid to dissolve out the iron [50] (Eq. 13.49). 

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