Why is cobalt usually recovered as a by-product of copper and nickel mining?

Cobalt is typically recovered as a by-product of copper and nickel mining because it is rarely found in concentrations high enough to justify mining for the cobalt content alone. Instead, it occurs as a trace element within the ores of metals such as copper, nickel, iron, silver, and zinc.1

Because cobalt is naturally dispersed within these host ores, it must be separated during the complex mineral processing and refining stages of the primary metal. For example, in copper smelting, cobalt enters the slag layer during conversion and is subsequently recovered as a copper-iron-cobalt alloy. In nickel production, cobalt is recovered through various methods, including precipitation during electrolytic refining, reduction with hydrogen in ammonia pressure leaching, or solvent extraction from chloride leach solutions.2

This reliance on by-product recovery is a result of the technical and economic necessity of extracting the metal from the larger volumes of primary ore being processed.1