GB336584A - Improvements relating to the treatment of complex ores of copper, cobalt and nickel - Google Patents

Abstract

336,584. Carreras, R. S. July 10, 1929. Copper, nickel, and cobalt, and their oxides. obtaining.-Ores containing copper, nickel and cobalt are leached with a mixture of dilute sulphuric acid and sodium chloride. The proportion of sodium chloride may be 5 per cent. The insoluble part of the ore, if any, which may contain arsenides and sulphocyanides is oxidized in a furnace and again leached and the solution added to the main bath or treated separately. The liquid, which should be of the concentration 13‹ to 15‹ BÚ., is electrolyzed for recovery of copper in wood vats lined with leads, using thin sheet copper cathodes and anodes of lead or of copper rendered inactive by preliminary treatment with nitric acid or of other metal rendered inactive bv treatment in a bath of an acid solution of a mercury compound. A current density of 0.6 amps. per sq. dcm. at 2 volts is used. The electrolyte is then concentrated by evaporation to a concentration of 28‹ BÚ. and cooled to precipitate alkaline-earth metal and magnesium salts and further concentrated to 38‹ BÚ., and cooled to crystallize out cobalt sulphate. The cobalt sulphate is dissolved to a concentration of 9-10‹ BÚ., and a quarter of its weight of ammonium sulphate and per cent of citric acid are added. The solution is electrolyzed using cathodes of copper-chrome and anodes of graphite or of inoxidizable steel or of other metal which has been rendered inactive. An initial voltage of 2.5 falling to 2, and a current density of 0.66 amps. per sq. dcm. are used. Cobalt is deposited in scales. Nickel is recovered from the remaining electrolyte, which may contain iron, in a similar manner to that employed for cobalt with the exception that in addition to ammonium sulphate, sodium sulphate and a small amount of ammonium carbonate are added to the liquor. Under some conditions the metals may be deposited as oxides.