Process for the production of nickel and cobalt from nickel and cobalt bearing material

Claim 1

IN A PROCESS FOR THE PRODUCTION OF A METAL SELECTED FROM THE GROUP CONSISTING OF NICKEL AND COBALT FROM OXIDIZED, LATERITIC AND GARNIERITIC NICKEL AND COBALT ORES IN WHICH THE ORE IS ROASTED IN A REDUCING ATMOSPHERE TO REDUCE NICKEL AND COBALT VALUES TO CRUDE METALLIC STATE AND FINELY DIVIDED PARTICLES OF REDUCED ORE ARE LEACHED WITH AN AMMONIACAL AMMONIUM CARBONATE SOLUTION IN THE PRESENCE OF A FREE OXYGEN CONTAINING GAS, THE IMPROVEMENT WHICH COMPRISES THE STEPS OF: (A) CONTINUING SAID LEACHING STEP TO OBTAIN SUBSTANTIALLY COMPLETE EXTRACTION OF NICKEL AND COBALT VALUES THEREFROM AND THEIR DISSOLUTION IN THE LEACH SOLUTION AS METAL CARBONATES; (B) SEPARATING UNDISSOLVED RESIDUE FROM THE LEACH SOLUTION; (C) HEATING SAID SOLUTION TO A TEMPERATURE ABOVE ITS BOILING TEMPERATURE; (D) CONTINUING SAID HEATING STEP TO EFFECT SUBSTANTIALLY COMPLETE PRECIPITATION FROM SAID SOLUTION OF DISSOLVED NICKEL AND COBALT VALUES AS METAL CARBONATES; (E) SEPARATING PRECIPITATED NICKEL AND COBALT CARBONATES FROM THE LEACH SOLUTION; (F) RE-LEACHING SAID NICKEL AND COBALT CARBONATES WITH AN AQUEOUS SOLUTION WHICH CONTAINS A MEMBER SELECTED FROM THE GROUP CONSISTING OF AMMONIA, AMMONIUM CARBONATE, AMMONIUM SULPHATE, ALKALI METAL HYDROXIDES AND INORGANIC ACIDS IN AMOUNT IN EXCESS OF THAT REQUIRED TO DISSOLVE SAID PRECIPITATED NICKEL AND COBALT CARBONATES; (G) CONTINUING SAID LEACHING STEP TO OBTAIN OPTIMUM DISSOLUTION OF SAID PRECIPITATED NICKEL AND COBALT CARBONATES; (H) SEPARATING UNDISSOLVED RESIDUE FROM THE LASTMENTIONED LEACH SOLUTION; (I) REACTING SAID LAST-MENTIONED LEACH SOLUTION WITH A SUPLHUR-FREE REDUCING GAS AT A TEMPERATURE OF FROM ABOUT 150*F. TO ABOUT 450*F. UNDER A PARTIAL PRESSURE OF A SULPHUR-FREE REDUCING GAS OF FROM ABOUT 20 TO ABOUT 1000 POUNDS PER SQUARE INCH; (J) PROVIDING IN SAID SOLUTION AN ACID NEUTRALIZING AGENT IN AMOUNT SUFFICIENT TO MAINTAIN THE PH OF SAID SOLUTION OF FROM ABOUT 2 TO ABOUT 10 DURING THE REDUCING REACTION; (K) CONTINUING SAID REDUCING REACTION TO PRECIPITATE NICKEL FROM SAID SOLUTION AS PRODUCT NICKEL METAL PARTICLES SUBSTANTIALLY FREE FROM IMPURITIES; AND (L) SEPARATING PRECIPITATED NICKEL METAL PARTICLES FROM THE LAST MENTIONED SOLUTION.