The Extraction of Nickel

Nickel was extracted on a commercial scale at Schneeberg, Saxony, and the chief ores were the arsenical minerals associated with the cobalt deposits of Saxony and Bohemia. In 1838, a plant for working the Swedish pyrrhotic ores was erected, and soon afterwards Norway began producing the metal from similar ores carrying 1.4 to 1.7 per cent, of nickel, and Norway became the main source of the world's supply. In 1877, the Norwegian ores were superseded by the garnieritic ores from New Caledonia; in 1886, Canada became a competitor with pyrrhotic ores, and, since 1905, she has been the main producer for the world's market.

The methods of extracting nickel vary according to the type of ore employed - sulphide, arsenide, or hydrosilicate. The ores furnish nickel, and in the two former cases, copper. In addition there are in some cases the by-products cobalt, gold, silver, and the platinum metals to be recovered. Some ores contain mercury.

The Sudbury ores are hard and compact so that the ore is mined without special difficulty, and mainly by underground workings. The ore is crushed and that portion which passes 1-inch trommel holes is known as fine. This amounts to about 30 per cent, of the ore mined. The ore is then carried on picking belts, where the so-called rock is picked out by hand. The rock thus discarded amounts to about 19 per cent, of the material hoisted from the mines. The discarded rock carries about 0.62 per cent, of nickel, and about 0.60 per cent, of copper, while the ore carries 3.58 per cent, of nickel and 1.58 per cent, of copper. The richer ore is directly smelted, whilst the lower grade ore has to be concentrated before smelting. The New Caledonia ore is friable and the depth of the workable ore is restricted to depths of 25 to 30 feet so that they are obtained from open pits. The ore is picked or barred down, and then sorted. The payable portion is gathered into heaps and then transported for shipment, or other treatment, and the waste is trammed to a dump. Flotation methods of concentration are not in general use at Sudbury, or New Caledonia. Magnetic concentration has been tried by C. E. Hugoniot, and G. C. Mackenzie; oil flotation was tried by H. E. T. Haultain, but the results were not successful.

Quite a number of papers have been written on the extraction of nickel; and there are also a number of special works devoted to the subject:

L. Ouvrard, Industries du chrom, du manganese, du nickel, et du cobalt, Paris, 1910; L. Herrenschmidt and E. Capelle, Le cobalt et le nickel, Rouen, 1888; H. Copaux, Recherckes experimental sur la cobalt et le nickel, Paris, 1905; J. Meunier, Cobalt et nickel, Paris, 1889; A. M. Villon, Cobalt et nickel, Paris, 1891; W. Borchers, Metallhuttenbetriebe - Nickel, Halle a. S., 1917; H. Moissan and L. Ouvrard, Le nickel, Paris, 1896; Report of the Royal Ontario Nickel Commission, Toronto, 1917; A. P. Coleman, The Nickel Industry, Ottawa, 1913; P. D. Merica, Trans. Canada Inst. Min. Met., 29. 1, 1926; W. H. Baldwin, Journ. Chem. Educ., 8. 2325, 1931; A. J. Wadhams, Metals Alloys, 2. 165, 1931; W. P. Blake, Chem. News, 48. 87, 1883; G. G. Urasoff and M. L. Tschernomorsky, The Metallurgy of Nickel, Moscow, 1931.

The general procedure in dealing with the sulphide ores involves,

1. Roasting of the ore. Pyritic smelting as employed for copper ores does not necessitate roasting; the process for nickel was tried by E. H. Robie.
2. Smelting the roasted ore for a regulus or crude matte,
3. Enriching the crude matte; and
4. Converting the enriched matte into crude metal.