Cominco plant

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. 

The Kivcet process is able to treat a wide variety of raw materials. The reported ratio of primary to secondary materials was 73 27 in one plant (Portovesme) and reversed in the second (Cominco). At the Cominco plant, the bulk of the secondary material consists of zinc leach residues. The flash smelting process, however, requires drying the feed material, prior to its being charged into the furnace, to a moisture content of less than 1%. 

Table 7.4 lists comparative design data for the four commercial plant designs to date. Note that the Cominco plant did not achieve design expectations and was replaced. 

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. 

The other author (WGD) has been interested in sulfuric acid plants since his 1957 student internship at Cominco s lead/zinc smelter in Trail, British Columbia. Cominco was making sulfuric acid from lead and zinc roaster offgases at that time. It was also making ammonium sulfate fertilizer. 

Although means are available for controlling the bulk of the emissions from the conventional lead and zinc smelters, new processes being developed offer greater economy as well as better emission control (9,10). Cominco Ltd. recently announced the development of a new process to replace the conventional lead smelting process with its sintering plants and blast furnaces (39). 

Existing single-contact acid plants can also be converted to doublecontact plants (63). In such cases, however, using add-on scrubber systems is an alternative, and several such systems have been used commercially. The Cominco ammonia absorption process has been used for many years (22, 64). The Lurgi Sulfacid process (65) and Wellman-Lord process (66) have had more recent and limited use. The Mitsu-bishi-JECCO process has also been applied to acid plant tail gases (27, 67, 68), but the gypsum by-product would be essentially a waste in the United States. 

Heavy-water production in Canada began on a small scale in a plant operated by Cominco for the United States Atomic Energy Commission (USAEC) in 1944 (14) and continued until 1956. This was also a period of initial research into heavy-water processes at CRNL (15). By the mid-1950 s the USAEC and the E. I. Dupont de Nemours and Company had put into operation two large, heavy-water plants using the GS process. The... 

As part of the Manhattan District Project during World War II, a small plant to produce heavy water 6 Mg/a) was built by Standard Oil Development Co. at Trail, B.C. and was operated by Cominco from 1944 to 1956 (14). It was based on steam-hydrogen catalytic exchange plus steam-water equilibration coupled to water electrolysis. However, byproduct heavy water from this process is economic only if the electrolysis cost is borne by the hydrogen product, which at Trail was used for ammonia production. In any case, the small scale of operation imposed by electrolytic capacity and the large exchange tower volume have made this production method economically unattractive. 

The new lead smelter is now operating at design rates. The majority of the charge is made up of zinc plant residues, Sullivan mine lead concentrate, and precious metal concentrates. The smelter has enabled Cominco to meet its objectives of reduced energy and labour costs and reduced enviroiunental impact. 

---