In the metallurgy of aluminium ……

In the metallurgy of aluminium, electrolysis is performed in a steel vessel with lining of carbon acts as cathode and graphite acts as anode. During this process graphite anode is oxidised to CO and CO2.Chemical reaction occuring in this process is as follows 2Al2O3+3C→4Al+3CO2This process is known as Hall-Heroult process. The electrolytic reactions are At cathode: Al3+(melt)+3e−→Al(l)At anode: C(s)+O2−(melt)→CO(g)+2e−                  C(s)+2O2−(melt)→CO2(g)+4e−