High-copper matte

Preparation. High purity nickel can be produced through electrolytic process or by the carbonyl process. In the latter case carbon monoxide reacts at 50°C with impure Ni (or nickel-copper matte) to give the volatile tetracarbonyl from which the metal (99.9-99.99% purity) is obtained by decomposition at 200-230°C through the reaction ... 

The application of ammonia pressure leaching as a method of refining nickel-cobalt matte has been studied (Bll, P3) and is considered an economically attractive process. Nickel-copper mattes with low cobalt content have been found to be readily leached with ammonia (P3). A high-nickel matte with a composition of 77% Ni, 0.1% Cu, 1.8% Co, 0.7% Fe, and 20% S is amenable to both acid and ammonia leach, but the sulfur deficiency can be made up more economically by circulation of ammonium sulfate solution within the process than by providing the sulfur through addition of sulfuric acid. 

Copper metal is the product of the oxidation of the copper matte. The more copper that is in the feed the better are the economics since co-smelting of copper is low-cost. Tr ped copper will have to be refined to give high-grade copper and to recover precious metals. The furnace product should be cast into anodes. 

Normally copper in lead smelter feed is sufficiently low to fully dissolve in bullion and be recovered by copper drossing as part of the refining stage. However, in the case of high copper feeds (above five per cent of the lead content), a matte can be formed during smelting. This will require retention of sufficient sulfur to form the matte, which tends to be a mixture of lead, iron and zinc sulfides as well as copper sulfide. 

The copper to sulfur ratio is important and with bullions low in sulfur content, such as from the Imperial Smelting Furnace, copper dross has a high content of metallic copper. The precipitated copper compounds are less dense than lead and float to the surface as a voluminous dross and are skimmed off. A significant amount of lead is entrained in the dross and further processing is useful to separate and recycle the entrained lead and yield a copper matte suitable for sale to a copper smelter. 

Low grade In a converter, air en- In the converter the sulfur High-grade copper matte. 

The high-grade matte from the converter process or the flash melting process contains sulfur and some amounts of copper, cobalt and iron and, in addition, traces of noble metals. Refined nickel is produced by a variety of methods and is delivered as nickel cathodes or nickel powder. The latter are produced partly by carbonyl processes, partly by hydrogen reduction in conjunction with pressure leaching processes. In the latter, matte is leached under pressure with acid or ammonia, and nickel is recovered as a powder by reduction with hydrogen under pressure. 

A special refining process is the carbonyl nickel process, an old process, which was invented in 1902 in Wales and used as the Langer-Mond process. Originally the plant treated nickel-copper matte but the process today is highly modified. The principle is a treatment at 60°C with carbon monoxide at atmospheric pressure. Nickel carbonyl, Ni(CO) is formed. This is a volatile Kquid that melts at -19.3°C and boils at 42.5°C. In this process nickel (and some iron) is carried off while other metals remain. Heating the gas to 180°C decomposes it and pure nickel powder is obtained. 

Observations of excess nasal and pulmonary cancers in people working with nickel oxide or high-temperature roasting of nickel-copper matte resulted in the suspi-... 

Being in a free state, Au and Ag in molten smelted product under high temperature has higher ionization potential, larger density and surface tension. Density and surface tension of copper matte increase with the increase of Cu in matte. Finally, the structure properties of droplets of matte and Dore metal become similar. Therefore, tension among phases for... 

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