Hall Heroult process : Electrolytic refining of Alumina ore of Aluminium:

Electrolysis of fused Alumina.

Cathode : Iron-tank lined with carbon bricks

Anode : carbon

Electrolyte : Molten [Al2O3

(5%) Na3AlF6 (85%) + CaF2 (5%) + AlF3 (5%) ]

O2 is liberated at anode and Al collects at the bottom.

Chemical refining methods:

(1) Oxidative refining:

(i) Bessemerisation : Purification of iron from cast Iron or pig iron :

(ii) Cupellation : lead (Pb) present in Silver removed by Cupellation process:

(2) Parting Process:

(3) Polling process: This process is used for the purification of copper and tin.

(4) Electrolytic Refining:

(5) Kroll's Process and Imperial metal industries (IMI) Process of reduction;

(6) Vapour phase refining:

(A) Vapour phase refining : Mond's process:

(B) Vapour phase refining : Van Arkel–De Boer process :

(7) Parke's Process: Desilverisation of lead ;

(8) Pudding process: Used for the manufacture of wrought iron from cast iron: