How is cobalt recovered during the electrolytic refining of nickel?

During the electrolytic refining of nickel, cobalt is primarily recovered by precipitation from the solution, typically in the form of cobaltic hydroxide.1

While this is the standard approach during nickel refining, it is worth noting that cobalt processing methods vary depending on the specific smelting or leaching technique employed. For instance, in nickel smelting, some cobalt may also be recovered from the final converter slag because it oxidizes before the nickel. In other nickel processing contexts, such as ammonia pressure leaching, cobalt is recovered from the solution through reduction with hydrogen under pressure. Additionally, refineries that utilize a chloride leach for nickel matte often employ solvent extraction to remove cobalt directly from the pregnant solution, which is then purified and prepared for recovery via electrowinning.1