State the role of silica in the metallurgy of Copper.

Explanation

During roasting, copper pyrites are converted into a mixture of FeO and `Cu_(2)O_(3)`
`2CuFeS_(2)+O_(2)overset(Delta)rarrCu_(2)S+2FeS+SO_(2)`
Copper pyrites
`2Cu_(2)S+3O_(2)overset(Delta)rarr2Cu_(2)O+2SO_(2)`
`2FeS+3O_(2)rarr2FeO+2SO_(2)`
To remove FeO (basic), an acidic flux silica is added during smelting. FeO then combines with `SiO_(2)` to form ferrous silicate `(FeSiO_(3))` slag floats over molten state.
`FeO+underset("Flux")(SiO_(2))rarrunderset("Slag")(FeSiO_(3))`
Thus, the role of silica in the metallurgy of copper is to remove iron oxide as slag.