In actual practice, the ore is heated in reverberatory furnace after mixing with silica. In the furnace, iron oxide 'slags off' as iron silicate and copper is produced in the form copper matte. This contains ${\mathrm{Cu}}_2\mathrm{S}$ and $\mathrm{FeS}$.

$\mathrm{FeO}+{\mathrm{SiO}}_2⟶{\mathrm{FeSiO}}_3$