During the roasting of pyrite ore, a mixture of FeO and Cu2O is obtained.
The role of silica in the metallurgy of copper is to remove the iron oxide obtained during
the process of roasting as ‘slag’. If the sulphide ore of copper contains iron, then silica (SiO2) is added as flux before roasting. Then, FeO combines with silica to form iron silicate, FeSiO3 (slag).
