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

Options

A. Auto-reduction of `Cu_(2)O` formed is carried out by remaining `Cu_(2)S` in the reaction.
B. Cu is separated out by partial reduction due to sedimentation
C. Due to difference in gravity `Cu_(2)O` and `Cu_(2)S` are separated.
D. Complete roasting cannot be done in one step hence partial roasting is done.

Answer

A

Explanation

Partial roasting of sulphide ore forms some oxide. This oxide then reduces the remaining sulphide ore into metal.
`2Cu_(2)S + 3O_(2) to 2Cu_(2)O + 2SO_(2)`
`2Cu_(2)O + Cu_(2)S to 6Cu + SO_(2)`
This process is called autoreduction.