Verfahren zur Rueckgewinnung von Nickel

摘要

The invention comprises a form of nickel oxide having a high packing density and which is produced by heating an ammoniacal ammonium carbonate solution of nickel carbonate to precipitate from 70 to 99% (preferably 85 to 95%) of the nickel as carbonate at a rate of 0.2 to 2 (preferably 0.5 to 1) g. nickel per litre per minute, and calcining the nickel carbonate formed in an atmosphere containing free oxygen. The rate of precipitation depends on the temperature at which the solution is heated, this being preferably 170 DEG to 250 DEG F. Such control of the precipitation yields a product having a packed bulk density of at least 75 lb./ft.3 If the calcination is carried out at 600 DEG to 1200 DEG F. for a period not exceeding 2 hours, a product having an oxygen content of from 0.1-5 atomic per cent in excess of the amount required by the formula NiO and whose solubility in acids is substantially complete is obtained. Nickel oxide according to the invention and containing less than 0.5% impurities may be obtained from impure nickel carbonate by purifying the carbonate by dissolving in an aqueous ammoniacal ammonium carbonate solution containing a soluble sulphide and separating the insoluble sulphides that are formed by reaction with the impurities.