SEPARATION OF COBALT FROM NICKEL AND COBALT BEARING AMMONIACAL SOLUTIONS

摘要

1344549 Cobalt and nickel separation SHERRITT GORDON MINES Ltd 14 Feb 1972 [5 March 1971] 6837/72 Heading C1A Nickel and cobalt bearing material is leached in one or more stages under oxidizing conditions with an ammonium salt leach solution, the solution from the leach operation being treated in at least two cobalt removal stages with a sulphidizing agent to form a mixed Nickelcobalt sulphide precipitate, the agent in one stage being sufficient to produce a Ni-Co ratio in the treated solution of 500 : 1 or over, the agent in another stage being sufficient to cause the precipitate formed therein to have a Ni-Co ratio of 2 : 1 or lower; the precipitate is removed from each stage and at least a portion is recycled to the solution from which it was removed, the un-recycled portion of the precipitate from the other stage is removed as mixed Ni-Co sulphide product and any unrecycled precipitate formed in said one stage is added to a further stage, at least a portion of solution from the other stage is recycled to the leach operation and the solution from said one stage is recovered as product liquor for subsequent treatment to yield nickel. Where three cobalt removal stages are used, 1, 2 and 3 in conjunction with two leaching stages, A and B, solution from A is treated in 2, the precipitate in 2 being separated and a portion being recycled to 2, the remainder with solution from B being passed to 3, solution from 2 being passed to 1 and the un-recycled portion of the precipitate from 1 is passed to 2. The sulphidizing agents may be H 2 S, (NH 4 ) 2 S, Na 2 S and NaHS. The product liquor may be maintained at 65-70‹ C. for a time sufficient to precipitate contained sulphides and manganese which are separated. The Ni-Co sulphide product may be washed with (NH 4 ) 2 CO 3 , the wash solution, after washing, being recycled to the leaching operation.