Method for Recovering Substantially Pure Nickel from Ammoniacal Nickel Ammonium Carbonate Leach Solutions.

摘要

1,150,188. Producing nickel. SHERRITT GORDON MINES Ltd. Feb. 2, 1968 [Feb. 15, 1967], No.5509/68. Headings C7D. Ammoniacal ammonium carbonate leach liquors containing Ni, S and other impurities are treated to recover substantially pure Ni powder as follows;- (a) The solution is boiled to drive off CO 2 and NH 3 to precipitate basic nickel carbonate (b) The precipitate is removed from the solution and then redissolved in substantially pure aqueous ammoniacal ammonium carbonate. (c) The solution is freed from insoluble impurities and boiled to precipitate at least some basic nickel carbonate. (d) The slurry is then treated with a free oxygen containing gas with an oxygen partial pressure above 5 p.s.i. at 65-260‹C. for a sufficient time to oxidize the impurity S content to SO 4 ". (e) Finally the slurry is reduced with H 2 at elevated temperature and pressure (e.g. at 80- 315‹C. with a partial pressure of H 2 of 100-500 p.s.i.). If the S content of the solution is above 0À1% it is preferred to treat the precipitated basic nickel carbonate of either precipitation with a sodium compound which will react with SO 4 " to form Na 2 SO 4 (e.g. hydroxide, carbonate or bicarbonate) either by adding the compound to the slurry or after removing the liquid therefrom by washing with a solution of the compound. Sub-micron Ni seed powder and/or a catalyst such as anthroquinone may be included in the slurry to be reduced.