Describe electolytic refining of copper with chemical equations. Draw a well labelled diagram for it.

Electrolytic refining: This method is used for the purification of metals like zinc (Zn), copper  (Cu),  aluminium (Al), chromium (Cr),  tin (Sn),   lead (Pb),  nickel (Ni), and gold (Au). In this process, impure metal is used as anode a strip of pure metal is used as a cathode and soluble salt of metal is used as an electrolyte. On passing electric current through the electrolyte cations move towards the cathode and pure metal gets deposited on the cathode.  

In the electrolytic refining of copper, the impure copper metal is made anode and a thin strip of pure copper metal is made cathode, a solution of the Copper salt is used as an electrolyte.

On passing the current through the electrolyte, the pure metal from the anode dissolves into the electrolyte. an equivalent amount of pure metal from the electrolyte is deposited on the cathode. The soluble impurities go into the solution, whereas, the insoluble impurities settle down at the bottom of the anode and are known as anode mud.

The following reactions take place at anode and cathode:

$Anode\ :\ Cu\rightarrow Cu^{2+} +2e^{-}$

$\ Cathode\ :\ Cu^{2+} +2e\ ^{-}\rightarrow Cu\ $