How is electrolysis used to purify metals through electrorefining?

Electrorefining is an electrolytic process used to achieve high-purity metals, such as copper, nickel, lead, gold, and silver, by leveraging the principles of electrochemical reactions.12

In this process, an impure slab of the target metal is cast to serve as the positively charged anode, while a pure sheet of the same metal acts as the cathode. Both electrodes are immersed in an aqueous electrolyte solution capable of conducting an electric current.12

When a direct current is applied:
* Anode Dissolution: The impure metal at the anode loses electrons (oxidation) and dissolves into the electrolyte as ions.32
* Cathode Deposition: These metal ions migrate through the solution to the cathode, where they gain electrons (reduction) and deposit in a highly pure metallic state.432
* Impurity Management: Impurities that do not dissolve remain as an insoluble sludge, often called anode slimes, which settles at the bottom of the cell and can be processed to recover valuable by-products.142

This method is highly effective, frequently producing metals with purity levels exceeding 99.9 percent.14