Cobalt recovery process

A process for producing purified cobalt from a mixture comprising metallic species of cobalt and metallic species of at least one of the group consisting of nickel and iron;

• said process comprising
• (i) reacting said metallic species with carbon monoxide to form a carbonyl mixture comprising cobalt carbonyl and nickel carbonyl and/or iron carbonyl, provided that when said metallic species comprises non-elemental metal species, said mixture is, optionally, first treated with a reducing agent to reduce said non-elemental metal species to said elemental metal;
• (ii) removing said nickel carbonyl and said iron carbonyl by distillation from said carbonyl mixture to provide a nickel- and iron-depleted impure cobalt carbonyl mixture;
• (iii) treating said impure cobalt carbonyl mixture with an effective amount of a complexing gaseous mixture of nitric oxide/carbon monoxide to produce cobalt nitrosyl tricarbonyl;
• (iv) decomposing said purified complex cobalt carbonyl to provide said purified cobalt and regenerated complexing gaseous mixture;
• and
• (v) removing said regenerated complexing gaseous mixture.

A process for producing purified cobalt from a mixture comprising metallic species of cobalt and metallic species of at least one of the group consisting of nickel and iron;

• said process comprising
• (i) treating said mixture in aqueous alkaline medium with hydrogen sulfide to effect reduction of metal species to soluble metallic species;
• (ii) subsequently treating said medium with carbon monoxide to produce cobalt carbonyl in admixture with nickel carbonyl and/or iron carbonyl in aqueous slurry;
• (iii) removing said nickel carbonyl, if any, by volatilization from said solution;
• to provide a nickel carbonyl depleted-solution but replace slurry with solution;
• (iv) treating said solution with an effective amount of a complexing gaseous nitric oxide/carbon monoxide mixture to produce cobalt nitrosyl tricarbonyl;
• (v) isolating said cobalt nitrosyl tricarbonyl by distillation to provide purified cobalt nitrosyl tricarbonyl;
• (vi) decomposing said purified cobalt nitrosyl tricarbonyl to provide said purified cobalt and regenerated complexing gaseous mixture;
• and
• (vii) removing said regenerated complexing gaseous mixture.

Apparatus for producing purified cobalt from a mixture comprising metallic species of cobalt and metallic species of at least one of the group consisting of nickel and iron, said apparatus comprising

• (i) means for producing a metal carbonyl mixture of cobalt carbonyl and at least one of said nickel carbonyl and iron carbonyl from said metallic species mixture;
• (ii) vaporization means for separating said nickel carbonyl and said iron carbonyl from said cobalt carbonyl to provide a resultant nickel carbonyl-and iron carbonyl- free mixture;
• (iii) means for treating said resultant mixture with an effective amount of a complexing gaseous mixture of nitric oxide/carbon monoxide to produce cobalt nitrosyl tricarbonyl;
• (iv) means for decomposing said cobalt nitrosyl tricarbonyl to provide said purified cobalt and regenerated complexing gaseous mixture;
• (v) means for recycling said regenerated complexing gaseous mixture to said means (iii) and
• (vi) continuously self-monitoring computer algorithmic microprocessor means for measuring, controlling and adjusting process parameters selected from the group consisting of temperature, pressure, gaseous input flow rates, gaseous output flow rates, metal carbonyl, carbon monoxide, nitric oxide and cobalt nitrosyl tricarbonyl concentrations in gaseous state and power supply.