The chemical process used for obtaining a metal from its oxide is reduction. In this process, metal oxides are reduced by using suitable reducing agents such as carbon or by highly reactive metals to displace the metals from their oxides.

For example, zinc oxide is reduced to metallic zinc by heating with carbon.

$Zn{{O}_{(s)}}\,+\,{{C}_{(s)}}\xrightarrow{\Delta }Z{{n}_{(s)}}\,+\,C{{O}_{(g)}}$

Manganese dioxide is reduced to manganese by treating it with aluminium powder. In this case, aluminium displaces manganese from its oxide.

$3Mn{{O}_{2(s)}}\,+\,4A{{l}_{(s)}}\,\to \,$ $3M{{n}_{(l)}}\,+\,2A{{l}_{2}}{{O}_{3(s)}}\,+\,Heat$

Oxides of more reactive metals are reduced by electrolysis.