This metal very much resembles iron in its properties. Its far more extensive use is precluded by nothing less than the natural scarcity of its ores. A few deposits of silicate mineral are known in the United States, but it never has been possible to produce the metal from them at a price to compete with the cost of production from the sulphide deposits of Canada and New Caledonia.
Nickel preserves its bright appearance remarkably well in ordinary air and therefore is used extensively as a coating or electroplate over more tarnishable metals. The electrolytic copper refineries produce some nickel from their electrolyte purifications which is available for this use.
The mining and early smelting processes, as carried out at the mines in Canada, are well known, but the companies attempt to suppress the later processes until we again see the metal and its alloys when ready for sale. At the mines in Canada the ores first are roasted, in the open or otherwise, then some type of blast smelting - blast furnace or converter - or, more recently, reverberatory smelting eliminates the gangue and produces a nickel-copper-iron matte. This is the end of the process as accomplished in Canada.
The Mond process is supposed to be used by the company of that name in England; it depends on the fact that, by the use of carbon monoxide, the nickel can be volatilized and thus separated from the other metals.
The process in use in the United States presumably is that of separating the sulphides of the metals with sodium sulphide, the heavier nickel sulphide separating below the layer of the other mixed sulphides. After this separation the sulphide must be roasted to oxide and the oxide then reduced to metal. The metal thus produced is by no means pure; there is apparently no difficulty in producing a very pure metal by electrolysis of this crude metal, and such is on the market.
Monel metal is the natural alloy produced by winning the metal from the nickel-copper matte without separation, presumably by roasting, and then by straight reduction with carbon. This alloy analyzes approximately Ni, 67 per cent; Cu, 27 per cent; Fe, 2 per cent; Mn, 3 per cent; and Si and C each 0.5 per cent. It is a strong, tenacious alloy, much like steel, but far more resistant to corrosion; because of the latter property it is finding much industrial application.