Canada acid-leaching process

D.T White, M.J. Miller and A.C. Napier, Impurity Disposition and Control in the Ravensthorpe Acid Leaching Process, Iron Control Technologies, J.E. Dutrizac and P.A. Riveros, Eds., CIM, Montreal, Quebec, Canada, 2006, 591-610. 

Falconbridge Also called the matte leach process. A process for extracting copper and nickel from matte (a sulfide ore that has been roasted to remove most of the sulfur). Most of the nickel is leached out with hydrochloric acid and recovered as nickel chloride crystals. The leach residue is roasted and leached with sulfuric acid to dissolve the copper. The process has been operated in Canada and Norway since 1970. 

By far the most important use of amine salt extractants is in the recovery of uranium from acidic leach liquors. The basic process was developed at the Oak Ridge National Laboratory in the USA,195 and essentially similar processes are currently in operation throughout the world. Examples of plant practice in the USA,196 Canada,197 Australia,198 South Africa199 200 and South West Africa201 have been described. 

The common sources of indium are the minerals dark sphalerite, christophite, and marmatite. Indium is also found in small amounts in manganese, tungsten, zinc, and tin ores. Rarely found as a free element, indium is commonly associated with gallium in tin and zinc ores. The main commercial source for indium is from zinc smelter flue dusts (Smith etal. 1977). Enrichment of indium from zinc residues is performed by acid leaching followed by chemical separation processes. Aqueous electrolysis of indium salts yields a final metal of 99.9% purity. Canada has the greatest resources of indium with approximately 27% of the world s reserves (based on estimated indium content of zinc reserves) and the United States has about 12% of the world reserves (Brown 2000). In recent years, there have been major improvements in the recovery, refining and recycling of... 

J.A. Johnson, etal. Process Water Salinity Effects in the Pressure Acid Leaching of Cawse Nickel Laterite Ore, Chloride Metallurgy 2002, E. Peek, G. Van Weert, Eds., CIM, Montreal, Quebec, Canada, vol. 1, 2002, 339-354. 

Cobalt can be recovered from nickel-sulfide concentrates or nickel matte by the Sherritt-Gordon ammonia leaching process in Fort Saskatchewan, Alberta, Canada, and it is also recovered from sulfuric-acid pressure leaching of laterites. In both cases, cobalt is obtained in nickel-free liquor by reduction with hydrogen under elevated pressure and temperature (Section 2.2). 

Hybinette A process for extracting nickel from sulfide ores. The nickel ore that occurs in Canada is a mixture of the sulfides of nickel, copper, and iron. Several methods have been used to separate these metals. In the Hybinette process, the ore is first smelted in a blast furnace, yielding a nickel-copper matte (i.e., a mixture of their lower sulfides). This is roasted to remove sulfur and leached with dilute sulfuric acid to remove copper. The resulting crude nickel oxide is used as the anode of an electrochemical cell. The nickel deposits on the cathode, which is contained in a cloth bag. Precious metals collect in the anode slime. The process was invented by N. V Hybinette in 1904 and operated at the Kristiansand refinery, Norway, from 1910. 

Many processes in nature require such a fine pH balance that they are dramatically upset by the shift that has occurred in the pH of rain. Thousands of lakes in the Adirondack region of upper New York State and in southeastern Canada have become so acidic that all fish life has disappeared. Massive tree die-offs have occurred throughout central and eastern Europe as acid rain has lowered the pH of the soil and leached nutrients from leaves. Countless marble statues have been slowly dissolved away as their calcium carbonate has been attacked by acid rain. 

Monk-Irwin An unsuccessful predecessor of the Sulfate process for making titanium dioxide pigment from ilmenite. Invented by C.R. Whittemore at McGill University, Montreal, in the early 1920s and subsequently developed by J. Irwin and R.H. Monk in Canada and B. Laporte Limited in Luton, UK. Ilmenite from the deposit at Ivry, Quebec was reduced by heating with coke, leached with ferric chloride solution, and then roasted with a mixture of sulfuric acid and sodium sulfate. The resulting cake, containing titanyl sulfate, was dissolved in water and hydrolyzed, and the titania hydrate calcined. Some of the product was extended with barium sulfate. The project was abandoned in 1928. 

TSR (2) [Tiomin Synthetic Rutile] A process for removing much of the iron from ilmenite in order to make a feedstock for titanium pigment manufacture. The ore is successively oxidized and reduced in fluidized beds, and then leached with hydrochloric acid. The product contains approximately 95% of titanium dioxide. Developed by Tiomin Resources, Canada, in the 1990s. Planned to be tested on a large scale in Queensland, Australia. 

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