Question

Why is the extraction of copper from pyrites more difficult than that from its oxide ore through reduction?

Answer 1

The Gibbs free energy of formation (ΔfG) of CS2 and H2S are more than Cu2S.

Therefore, the C and H2 cannot produce the Cu from the Cu2S.

The Gibbs free energy of formation (ΔfG) of Cu2O is more than CO.

As a result, C can produce Cu from Cu2O. C(s) +Cu2O(s) → 2Cu(s) + CO(g).

Therefore,the extraction of the copper from the copper pyrite ore is more difficult than from the oxide ore by reduction.

Answer 2

the Gibbs free energy of formation of Cu2O is greater than that of CO. Hence, C can reduce Cu2O to Cu. Hence, the extraction of copper from its pyrite ore is difficult than from its oxide ore through reduction.