Refining of metals – removing impurities or gangue from crude metal. It is the last step in metallurgy and is based on the difference between the properties of metal and the gangue.
Electrolytic Refining
Metals like copper, zinc, nickel, silver, tin, gold etc., are refined electrolytically.
Anode: impure or crude metal
Cathode: a thin strip of pure metal
Electrolyte: aqueous solution of metal salt
From anode (oxidation): metal ions are released into the solution
At cathode (reduction): the equivalent amount of metal from solution is deposited
Impurities deposit at the bottom of the anode.
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