Refining of Aluminium by Hoope’s Electrolytic Method

Refining of Aluminium by Hoope’s Electrolytic Method:- Aluminium is further purified by Hoope’s process. The electrolytic cell consists of an iron box lined inside with carbon. The cell consists of three layers which differ in specific gravities.

a)   The upper layer is of pure aluminium which acts as cathode.

b)   The middle layer consists of a mixture of the fluorides of Al, Ba and Na.

c)   The lowest layer consists of impure aluminium which acts as anode.

On electrolysis, aluminium is deposited at cathode form the middle layer and an equivalent amount of aluminium is taken up by the middle layer from the bottom layer. Therefore, aluminium is transferred from bottom to the top layer through middle layer while the impurities are left behind.