The purpose of smelting of an ore is

Smelting involves reduction of ore to the molten metal at a high temperature. For the extraction of less electropositive metals such as Pb, Zn, Fe, Sn, etc., powerful reducing carbon reduction reduce by agents such as C, H₂, CO, water gas, Na, K, Mg, Al may be used.

$Ex:\hspace{0.17em} ZnO +\hspace{0.17em}C \stackrel{ }{\to }Zn +\hspace{0.17em}CO\hspace{0.17em}$