Patent ID: 6409979
Filing Date: 2002-06-25
Classification: C22B

Abstract:
A method for precipitating nickel and cobalt from an acid aqueous solution containing at least dissolve nickel, cobalt an manganese, the method including the steps of:(a) determining amounts of nickel, cobalt and manganese in the acid aqueous solution; (b) determining an amount of magnesium oxide required to effect precipitation of a substantial proportion of the nickel and cobalt in solution and to effect precipitation of a minor proportion of the manganese in solution to form a solid precipitate including nickel, cobalt and manganese such that a weight ratio of (Ni+Co)/ in the solid precipitate is at least five times larger than a weight ratio of (Ni+Co)/Min in the acid aqueous solution; (c) adding the determined amount of magnesium oxide, in the form of solid caustic calcined magnesium oxide or freshly slurred magnesium oxide, to the aqueous solution; (d) maintaining the magnesium oxide in contact with the acid aqueous solution for a period of from about 1 hour to about 9 hour to thereby achieve precipitation of the substantial proportion of the nickel and cobalt in solution and the minor proportion of the manganese in solution such that the weight ratio of (Ni+Co)/Mn in the solid precipitate is at least five times larger than the weight ratio of (Ni+Co)/Mn in the acid aqueous solution supplied to step (c); and (e) separating a mixture from step (d) into precipitated solids and a liquor.