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JEE Advance - Chemistry (2010 - Paper 1 Offline - No. 22)

Copper is the most noble of the first row transition metals and occurs in small deposits in several countries. Ores of copper inculcated chalcanthite (CuSO$$_4$$ . 5H$$_2$$O), atacamite (Cu$$_2$$Cl(OH)$$_3$$), cuprite (Cu$$_2$$O), copper glance (Cu$$_2$$S) and malacite (Cu$$_2$$(OH)$$_2$$CO$$_3$$). However, 80% of the world copper production comes from the ore of chalcopyrite (CuFeS$$_2$$). The extraction of copper from chalcopynite involves partial roasting, removal of iron and self-reduction.
Copper is the most noble of the first row transition metals and occurs in small deposits in several countries. Ores of copper inculcated chalcanthite (CuSO$$_4$$ . 5H$$_2$$O), atacamite (Cu$$_2$$Cl(OH)$$_3$$), cuprite (Cu$$_2$$O), copper glance (Cu$$_2$$S) and malacite (Cu$$_2$$(OH)$$_2$$CO$$_3$$). However, 80% of the world copper production comes from the ore of chalcopyrite (CuFeS$$_2$$). The extraction of copper from chalcopynite involves partial roasting, removal of iron and self-reduction.
Copper is the most noble of the first row transition metals and occurs in small deposits in several countries. Ores of copper inculcated chalcanthite (CuSO$$_4$$ . 5H$$_2$$O), atacamite (Cu$$_2$$Cl(OH)$$_3$$), cuprite (Cu$$_2$$O), copper glance (Cu$$_2$$S) and malacite (Cu$$_2$$(OH)$$_2$$CO$$_3$$). However, 80% of the world copper production comes from the ore of chalcopyrite (CuFeS$$_2$$). The extraction of copper from chalcopynite involves partial roasting, removal of iron and self-reduction.
Partial roasting of chalcopyrite produces
Cu$$_2$$S and FeO
Cu$$_2$$O and FeO
CuS and Fe$$_2$$O$$_3$$
Cu$$_2$$O and Fe$$_2$$O$$_3$$

Explanation

Partial roasting of chalcopyrite gives

2CuFeS$$_2$$ + O$$_2$$ $$\to$$ Cu$$_2$$S + 2FeS + SO$$_2$$

2CuFeS$$_2$$ + 4O$$_2$$ $$\to$$ Cu$$_2$$S + 2FeO + 3SO$$_2$$

Since iron is more electropositive than copper, so its sulphide is oxidised in preference. Cu$$_2$$S remains mostly unaffected and the small amount of Cu$$_2$$O formed on oxidation, reacts with FeS to give back Cu$$_2$$S.

2Cu$$_2$$S + 3O$$_2$$ $$\to$$ 2Cu$$_2$$O + 2SO$$_2$$

Cu$$_2$$O + FeS $$\to$$ Cu$$_2$$S + FeO

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