Copper is the most noble of first row transition metals and occurs in small deposits in several countries. Ores of copper include chalcanthite CuSO4⋅5H2O atacanite Cu2Cl(OH)3 cuprite Cu2O copper glance Cu2S, and malachite Cu2(OH)2CO3. However, 80% of the world copper production comes from the ore chalcopyrite CuFeS2. The extraction of copper from chalcopyrite involves partial roasing, removal of iron and self-reduction.Partial roasting of chalcopyrite producesIron is removed from chalcopyrite asIn self-reduction, the reducing species is

During partial roasting, CuFeS2 is first converted to Cu2S and FeS. Further, as iron is more reactive than copper, FeS. is preferentially oxidised to FeO. This partial roasting of chalcopyrite produces Cu2S and FeO.CuFeS2+O2⟶ΔCu2S+2FeS+SO22FeS+O2⟶ΔCu2S+2FeS+SO2The partially roasted ore is mixed with silica and little coke and then is heated in a blast furnace when FeO, which is present as impurity is removed as ferrous silicate slag. FeOSiO2⟶FeSiO3↓During self-reduction, Cu2S, i.e. S2−- ion acts as a reducing species and hence reduces Cu2O to Cu metal.Cu2S+2Cu2O⟶6Cu+SO2