What is the role of silica in the metallurgy of copper?
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. 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).
In the Roasting process of Copper Pyrite the following reactions occur:
Now, 2Cu2S+3O2------> 2Cu2O+ 2SO2
2FeS+3O2---> 2FeO+ 2SO2
Now, a Mixture of Cu2O and FeO is obtained. Now we need to separate the FeO to carry out further reaction in the extraction of metallic copper. This is done through Silica lined covers. SiO2 combines with FeO to form slag(FeSiO3)