Hydrometallurgical process for the production of cobalt powder from mixed metal sulphides

Claim 1

A process for recovering metallic cobalt from mixed sulphide materials containing sulphides of cobalt and of at least one metal selected from the group consisting of nickel and copper, said process comprising leaching said mixed sulphide materials with an aqueous ammoniacal solution in the presence of oxygen to dissolve cobalt and said at least one metal as ammine sulphates and convert substantially all dissolved cobalt values to the cobaltic form, separating the resulting cobalt and said at least one metal bearing leach solution from undissolved residue and contacting said separated leach solution with a water immiscible liquid organic ion exchange reagent dissolved in an inert organic diluent to selectively substantially completely extract said at least one metal from said leach solution and produce an aqueous cobalt bearing raffinate substantially free of said at least one metal and an organic extractant phase loaded with said at least one metal, washing said loaded organic extractant phase to remove substantially all ammonia therefrom, contacting said loaded and washed organic extractant phase acid solution to strip said at least one metal therefrom, separating the resulting said at least one metal bearing aqueous acid solution from the resulting stripped organic extractant phase, washing said stripped organic extractant with a wash liquid to remove values of said at least one metal therefrom, using said wash liquid after said washing of said stripped organic extractant to effect said washing of said loaded organic extractant, recycling said stripped and washed organic extractant to treat additional leach solution for extraction of said at least one metal therefrom, treating said cobalt bearing raffinate to reduce substantially all cobaltic cobalt values to cobaltous form, and reacting the resultant cobaltous cobalt bearing solution with hydrogen at elevated temperature and pressure to precipitate dissolved cobalt in metallic powder form and recovering said cobalt powder from the reduced end solution.