Production of nickel-copper ores in the Sudbury district began in 1887. On account of the copper with the nickel in these ores, new processes of refining had to be worked out and the trade prejudice against the product had to be overcome. This took persistent effort for several years. Only one of the first companies to operate in the Sudbury district has survived to the present time. This is the Canadian Copper Co., the producing subsidiary of the International Nickel Co.
Three new refining processes have been developed to handle nickel-copper ores. The Orford Copper Co. (subsidiary of the International company) uses the salt cake process. This process is one of fusion with sodium sulphide, the copper sulphide concentrating on top and the nickel sulphides at the bottom of the melt. Repeated fusion of the “tops” and “bottoms” effects a good separation.
The Mond company had a process before it had any mines. This process depends upon volatilization of the nickel by passing carbon monoxide over the matte, which has been previously roasted and leached of its copper content. Nickel carbonyl, Ni(CO)4, is formed and metallic nickel is thrown down by decomposition of this product, so that the nickel obtained is pure.
The Hybinette process, a process depending on electrolysis, was first worked out at the plant of the Orford Copper Co. on Sudbury matte. It was used for low-grade ores at Fredericktown, Mo., and then later for the Norwegian ores at Kristiansand. It is to be used in the new refinery of the British-American Co. in Ontario.
Monel metal is made directly from Sudbury matte with the removal of a little of the copper. It is known as a natural alloy, in contrast to one made by combining the pure metals.
Increased use of nickeliferous iron ore for steel making will decrease the amount of nickel that will have to be added in making such steel. This will probably be overbalanced by the increased use of such steels.
GEOLOGICAL DISTRIBUTION
Analyses of igneous rocks indicate that nickel is present in the average igneous rock to the extent of 0.020[68] per cent. Of its occurrence, Clarke says:[69] “Very frequently detected in igneous rocks, probably as a constituent of olivine. * * * The presence of nickel is especially characteristic of magnesian igneous rocks, and it is generally associated in them with chromium.” Regarding copper he says: “Minute traces of this metal are often detected in igneous rocks, although they are rarely determined quantitatively.” It is estimated[70] that copper is present in the average igneous rock to the proportion of about 0.010 per cent., or only about half that of nickel, and that zinc and lead are present in even smaller proportion. Notwithstanding this greater abundance of nickel, the workable deposits of copper, lead, and zinc are much more widespread and production is correspondingly greater. “It can thus be said that nickel is less amenable to concentration by the agencies that tend to produce workable deposits than are the other metals mentioned (copper, lead and zinc).”[71]
[68] F. W. Clarke, “The Data of Geochemistry,” Bull. 616, U. S. Geological Survey, 1916, p. 27.
[69] Ibid., p. 18.