(1) The process of obtaining the pure metal from the impure metal is called refining of the metal. 

(2) Some of the processes of refining are : 

(i) Distillation 

(ii) Poling 

(iii) Liquation 

(iv) Electrolytic refining. 

(3) The process that has to be adopted for purification of a given metal depends on the nature of the metal and its impurities.

(i) Distillation : This method is very useful for purification of low boiling metals like zinc (Zn) and mercury (Hg) containing high boiling metals as impurities. The extracted metal in the molten state is distilled to obtain the pure metal as distillate.

(ii) Poling : The molten metal is stirred with logs of green wood. The impurities are removed either as gases or they get oxidised and form sum (slag) over the surface of the molten metal. Blister copper is purified by this method.

(iii) Liquation : In this method, a low melting metal like Tin can be made to flow on a slope surface to separate it from high melting impurities. 

(iv) Electrolytic refining : 

(1) In this method, the impure metal is made to act as anode. 

(2) A strip of the same metal in pure form is used as cathode. 

(3) They are put in a suitable electrolytic bath containing soluble salt of the same metal. 

(4) The required metal gets deposited on the cathode in the pure form.

(5) The metal constituting impurity, goes as the anode mud.

The reactions are :

At anode : M→ M^{n +} + n.e^– 

At cathode : Mⁿ⁺ + n.e^–→ M

(M = pure metal, n = 1, 2, 3, .......)