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

Everyone knows: $$\ce{Mg +Al2O3->MgO +Al}$$ This reaction is thermodynamically feasible. Use can we this for reduction of Alumina. And produce Aluminium. Then why don't we not use this why?

If you compare the magnesium price (about 2$per pound) to the aluminum price (about$0.80 per pound)