Refining

The mond?? process is used for refining of nickel as per following reaction. \underset{\text{Impure}}{ {Ni}} +CO(g) \underset{\text{}}{ {}} \underset{\text{Pure}}{ {Ni (s)}} \underset{\text{}}{ {}}

The copper ore contains iron, it is mixed with silica before heating in reverberatory furnace. $FeO$ slags off as $FeSi{O}_3$.
$FeO+Si{O}_2⟶FeSi{O}_3$