Question

What is the role of graphite in the electrometallurgy of aluminium?

Answer 1

Graphite rod is used as an anode and graphite line iron as cathode during the electrolysis of alumina. During the electrolysis aluminium is liberated at the cathode and oxygen at the anode. This oxygen reacts with the graphite anode to for $CO$ and $C{O}_2$ preventing the oxygen evolved from oxidizing aluminium. Thus the role of graphite in electrometallurgy of aluminium is to prevent the liberation of oxygen so that the aluminium is not oxidized by oxygen.