Electrolytic Refining 

 

We shall understand electrolytic refining of metals by taking the example of refining of copper. In case of copper, a thick block of impure copper is made anode and a thin block of pure metal is made cathode and copper sulphate solution is used as an electrolyte. On passing electric current, pure copper metal from the electrolyte solution deposits on the cathode. At the same time an equal amount of impure copper dissolves from anode into the electrolyte solution. The soluble impurities settle down in the solution below the anode and are called as anode mud.
Many metals like Cu, Zn, Pb, Cr, Ni, Ag, and Au are refined electrolytically for refining of an impure metal by electrolysis.