The extraction of nickel from arsenical ores

The extraction of nickel from arsenical ores - e.g., niccolite or kupfernickel, chloanthite, and nickel glance. Arsenical ores are now very little worked. The ores, freed from gangue, were first roasted to remove some of the arsenic. The iron can be nearly all oxidized and slagged before the nickel arsenide is attacked. This furnishes a crude speiss. The crude speiss is again roasted and enriched by a second fusion to furnish an enriched speiss. The operations are here analogous to those employed in the preparation of the coarse and enriched mattes in working with sulphide ores, only now, in the roasting, stable arsenates are formed. The roasted charge is therefore mixed with carbon strongly heated so as to reduce the arsenate to arsenide. The arsenic can also be removed by heating the nickel arsenide with nitre and soda whereby the nickel furnishes nickel oxide, and the arsenic a soluble arsenate which can be removed by leaching with water. The arsenic can also be removed as volatile chloride by the chloridizing roast with common salt. The nickel oxide can then be reduced in the usual manner.