How is electrolysis used to extract metals from ores through electrowinning?

Electrowinning, also known as electrolytic deposition, is a hydrometallurgical process used to recover metals from solution in a pure, solid form. It is a critical step in the extraction of metals like copper, zinc, nickel, and cobalt.12

The Electrowinning Process

The process typically follows these steps:

• Leaching: Metallic compounds are selectively dissolved from an ore using an aqueous solvent to create a "pregnant" leach solution.13
• Preparation: Because electrowinning requires a solution with high metal content, dilute solutions are often concentrated first through methods like [solvent extraction].1
• Electrolysis: The solution is placed in an electrolytic cell containing insoluble anodes and cathodes (often made of a strippable inert material or a thin sheet of the target metal).12
• Deposition: When a direct electric current is passed through the cell, the metal ions in the solution are reduced and deposit onto the cathode.12

Unlike electrorefining, where metal is dissolved from an impure anode, electrowinning removes metal directly from the solution. While effective at producing high-purity products, the process is energy-intensive and requires careful control of solution purity to ensure successful deposition.241