Answer. Electro-refining of copper carried out in an electrolytic tank. It consists of two electrodes; anode of impure copper and cathode of pure copper metal. In the process oxidation takes place at anode. As a result, copper atoms of the anode lose two electrons at the anode and copper ion (Cu2+) dissolves into the solution.
Cu ———> Cu2+ + 2e;
Simultaneously, Cu2+ ions from the solution reduce and deposit at the cathode. The process continues by dissolving of anode and depositing of Cu2+ ions at cathode. Meanwhile, ultimately the anode is eaten up.