Question

Why is partial roasting of sulphide ore done in metallurgy of copper?

• A. Auto reduction of CuO formed is carried out by remaining CuS in the reaction.
• B. Cu is separated out by partial reduction due to sedimentation.
• C. Due to difference in gravity CuO and CuS are separated.
• D. Complete roasting cannot be done in one step hence partial roasting is done.

Answer 1

Answer: (A)

Auto reduction of CuO formed is carried out by remaining CuS in the reaction.

Answer 2

Partial roasting of sulphide ore forms some oxide this oxide then reduces the remaining sulphide ore into metal.

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

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

This process is called auto reduction