Recovery of nickel and cobalt values from garnierite ores

Claim 1

IN A PROCESS OF TREATING AN AQUEOUS SLURRY OF UNREDUCED AND UNROASTED GARNIERITE ORE WITH SULPHUR DIOXIDE GAS AND SEPARATED VALUES IN NICKEL AND COBALT FROM DILUENT MAGNESIUM AND IRON IN SOLUTION, THE IMPROVEMENT WHICH COMPRISES: SUPPLYING SAID SLURRY WITH SULPHUR DIOXIDE GAS IN SUFFICIENT AMOUNT TO PRODUCE A POSTIVE OVERPRESSURE WHILE MAINTAINING A TEMPERATURE OF FROM ABOUT 30*C. TO ABOUT 200*C.; MAINTAINING SAID TEMPERATURE AND PRESSURE UNTIL NON-FERROUS METAL EXTRACTION SUBSTANTIALLY CEASES; SEPARATING RESIDUAL SOLIDS FROM RESULTANT LEACH LIQUOR, WHEREBY A SOLUTION IS OBTAINED COMPRISING DISSOLVED SULPHUR-CONTAINING SALTS OF NICKEL, MAGNESIUM, IRON AND SALTS OF COBALT WHEN THE ORE CONTAINS COBALT; TREATING SAID SOLUTION TO A TEMPERATURE OF FROM ABOUT 70*C. TO ABOUT 100*C. FOR SUFFICIENT TIME TO EFFECT PRECIPITATION OF MAGNESIUM AS A SULPHITESALT IN EXCESS OF 10-12 GRAMS OF MAGNESIUM PER LITER; COLLECTING MAGNESIUM-BEARING PRECIPITATE; CALCINING SAID PRECIPITATE TO PRODUCE MAGNESIUM OXDE AND SULPHUR DIOXIDE; COLLECTING SAID MAGNESIUM OXIDE AND TREATING SAID SOLUTION OF REDUCED MAGNESIUM CONTENT WITH COLLECTED MAGNESIUM OXIDE TO PRECIPITATE INSOLUBLE OXIDE COMPOUNDS OF NICKEL AND COBALT.