Patent ID: 8486355

Claim:
A method for leaching cobalt from a non-lateritic oxidised cobalt ore, the method comprising the method steps of: curing the non-lateritic oxidised cobalt ore by application of an aqueous solution of a cobalt reducing agent selected from the group consisting of: iron (II) salts, sulfite salts, sulfur dioxide, and combinations thereof; at a pressure of between about atmospheric pressure and about 5 atmospheres, at a temperature between about 5° C. and about 65° C.; wherein the pH of the aqueous solution of the cobalt reducing agent is between about 1.0 and 10.0; and wherein the combination of the aqueous solution of the cobalt reducing agent and the non-lateritic oxidised cobalt ore forms a mixture having a solids content not less than about 100 g/L of aqueous solution; substantially retaining the aqueous solution of the cobalt reducing agent in contact with the non-lateritic oxidised cobalt ore; and leaching the cured ore at a pressure of between about atmospheric pressure and about 5 atmospheres, at a temperature between about 5° C. and about 65° C., through the application of an ammonium carbonate solution containing free ammonia thereby producing a pregnant leach solution; then passing the pregnant leach solution to a means for cobalt recovery.