What is electrowinning used for in cobalt refining?

In the context of cobalt refining, electrowinning—often referred to as electrolysis—is the final process used to recover cobalt in its metallic state from a purified, concentrated solution.12

The specific application of this process depends on the source material:

• From Nickel Smelting: In refineries that utilize a chloride leach for nickel matte, solvent extraction is used to isolate cobalt from the pregnant solution. Once this solution undergoes purification, it is processed via electrowinning to recover the cobalt.1
• From Copper-Cobalt Ores: When processing sulfide concentrates, the material is roasted and leached to create a solution. After copper and iron are removed, the cobalt is recovered through electrolysis.2
• From Oxidized Ores: If copper and cobalt ores are in an oxidized state, copper is first removed via electrolysis in a sulfuric acid solution. The cobalt is then precipitated from the remaining electrolyte and subsequently obtained in its metallic form through further electrolysis.2