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, comprising producing a metal carbonyl mixture of cobalt carbonyl and at least one of nickel carbonyl and iron carbonyl from the metallic species mixture; separating the nickel carbonyl and/or iron carbonyl from the cobalt carbonyl; treating the cobalt carbonyl with an effective amount of a complexing gaseous mixture of nitric oxide/carbon monoxide to produce cobalt nitrosyl tricarbonyl; and decomposing the purified cobalt nitrosyl carbonyl to provide purified cobalt and regenerated complexing gaseous mixture for recycle. The process provides cobalt of improved quality in an optionally, Continuous and closed-loop manner. Preferred processes include either aqueous and/or gaseous process steps.