- The impure metal is taken as anode and pure metal is taken as cathode.
- They are put in a suitable electrolytic bath containing soluble salts of same metal.
- The required metal gets deposited on the cathode in the pure form.
- The metal constituting the impurity goes as the anode mud.
Examples :
- In order to refine copper, impure copper is taken as anode and pure copper strips are taken as cathode.
- The electrolyte is an acidified solution of copper sulphate.
- As a result of electrolysis copper in pure form is transferred from anode to cathode.
- The suitable impurities go into the solution.
- Whereas insoluble impurities from the blister copper deposited at the bottom of anode as anode mud.