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Extraction of copper from copper pyrite $(CuFeS_{2})$ involves

A) crushing followed by concentration of the ore by froth-floatation

B) removal of iron as slag

C) self reduction step to produce 'blister copper' following evolution of

$SO_{2}$

D) refining of 'blister copper' by carbon reduction

Option A,B,C

$CuFeS_{2}$ ( copper pyrite) is converted into copper in the following steps,

Step I: Crushing (grinding) followed by concentration by the froth-floatation process.

Step II: Roasting of ore in the presence of $SiO_{2}$ which removes iron as slag $(FeSiO_{3}).$

$2CuFeS_{2}+O_{2}\rightarrow Cu_{2}S+2FeS+SO_{2}$

$2FeS+3O_{2}\rightarrow 2SO_{2}+2FeO$

$FeO+SiO_{2}\rightarrow FeSiO_{3}(slag)$

Step III,

Self reduction in Bessemer converter

$2Cu_{2}S+3O_{2}\rightarrow 2Cu_{2}O+2SO_{2}$

$2Cu_{2}O+Cu_{2}S\rightarrow 6Cu+SO_{2}$

Copper obtained is blister copper (98% pure)

Step IV,

Refining of blister copper is done by electrolysis

impure copper→ Anode

Pure copper → Cathode

At anode : $Cu\rightarrow Cu^{2+}+2e^{-}$

At cathode: $Cu^{2+}+2e^{-}\rightarrow Cu$

Carbon-reduction method is not used, Thus (d) is incorrect

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