Copper is refined using an electrolytic method. In this method, crude copper is made anode, a thin sheet of pure copper is made cathode and acidified solution of copper sulphate is used as an electrolyte. On passing electric current, metal ions from the electrolyte are deposited at the cathode in the form of pure metal. On the other hand, an equivalent amount of metal dissolves from the anode into the electrolyte in the form of metal ions. The reactions occurring at electrode are :
At cathode : Cu2+ + 2e– → Cu
At anode : Cu → Cu2+ + 2e–
The impurities settle down below the anode in the form of anode mud.
