Political and commercial geology and the world's mineral resources

by Unknown

CHANGES IN PRACTICE

Production of nickel on a fairly large scale did not begin until the mines of New Caledonia were opened in 1875. To handle these ores, smelters and refineries were built in England and continental Europe. As the ores are of the silicate type and free from copper, they were easily treated by common processes of smelting with fluxes to get rid of the gangue and then heating with charcoal for reduction to a metallic condition. A pure metal was obtained which found a good market.

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.