Question

Although thermodynamically feasible, in practice, magnesium metal is not used for the reduction of alumina in the metallurgy of Aluminium. Why?

Answer 1

The process would be uneconomic because Mg itself is a costly metal. Moreover, there is one technological difficulty also. The reaction between Mg and Al₂O₃ is exothermic. If the temperature increases to 2000 K then the reverse reaction becomes feasible, i.e., Al starts reducing MgO.