Explain the extraction/purification of copper.

(N/A) The $\Delta_{r} G^{\circ}$ vs $T$ plot for the formation of $Cu_{2}O$ is almost at the top.
Therefore,the reduction of copper oxide ore to metal by heating with coke is very easy.
Both $(C, CO)$ and $(C, CO_{2})$ lines are at much lower positions in the graph,especially above $500-600 \ K$. Furthermore,some ores are sulfides and some also contain iron.
Roasting/smelting of sulfide ore gives the oxide:
$2 Cu_{2}S + 3 O_{2} \rightarrow 2 Cu_{2}O + 2 SO_{2}$
Then,the oxide can be easily reduced to metallic copper using coke:
$Cu_{2}O + C \rightarrow 2 Cu + CO$
In the process,the ore is mixed with silica and heated in a reverberatory furnace.
In the furnace,iron oxide is formed as iron silicate slag,and copper is obtained in the form of copper matte,which contains $Cu_{2}S$ and $FeS$:
$FeO + SiO_{2} \rightarrow FeSiO_{3} \text{ (slag)}$
Then,the copper matte is taken into a silica-lined converter. Some silica is added,and a blast of hot air is blown.
Thus,the remaining $FeS$ is converted to $FeO$ and $Cu_{2}S/Cu_{2}O$ is converted to copper metal,represented by the following reactions:
$2 FeS + 3 O_{2} \rightarrow 2 FeO + 2 SO_{2}$
$FeO + SiO_{2} \rightarrow FeSiO_{3}$
$2 Cu_{2}S + 3 O_{2} \rightarrow 2 Cu_{2}O + 2 SO_{2}$
$2 Cu_{2}O + Cu_{2}S \rightarrow 6 Cu + SO_{2}$
The copper obtained in solid form has blisters due to the evolution of $SO_{2}$,hence it is called blister copper.