PRODUCTION OF NICKEL POWDER FROM BASIC NICKEL CARBONATE

1345118 Producing nickel powder SHERRITT : GORDON MINES Ltd 9 May 1972 [14 June 1971] 21654/72 Heading C7D A process for the production of Ni powder from nickel carbonate containing S and any of Mg, Al, Mn, Co, Zn Fe and SiO 2 as impurities comprises making an aqueous slurry of the carbonate, oxidizing if necessary any S not in sulphate form to sulphates, adding at least 1À8 moles NH 3 (or other alkali, e.g. hydroxides or carbonates of Na, K) per mole of S, and reducing with H 2 . The reduction is carried out in an autoclave in the range 80-325‹C and 100- 500 psi, producing a reduction end solution and a solid deposit of Ni powder plus compounds of the impurities, the Ni powder being separated by magnetic decantation or elutriation. A portion of the reduction end solution may be used to make up the slurry. The NH 3 is preferably added as (NH 4 ) 2 CO 3 . The basic nickel carbonate is obtained from leaching Ni ores, e.g. laterite, with ammoniacal ammonium carbonate solution.