Answer:
Option A,B,C
Explanation:
$CuFeS_{2}$ ( 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
