Question

How electrolysis can be used in extraction of aluminium?

Answer 1

Aluminium is extracted by the electrolysis of fused pure alumina dissolved in a fused mixture of cryolite and fluorspar. This mixture lowers the melting point of alumina and increases the electrical conductivity, and the electrolysis
is carried out in an iron tank lined with gas carbon. This carbon lining serves as the cathode. The anode consists of a number of carbon rods which dip in fused electrolyte. When an electric current passes, the following reaction takes place.

At Cathode: \[\ce{Al^{+3} + 3e- -> Al}\]

At anode: \[\ce{O^{2-} - 2e- -> O}\]

\[\ce{O + O -> O2}\]