Why is the extraction of copper form pyries more difficult then that from its oxide ore through reduction?

Explanation

The extraction of copper from pyrites is more difficult than that from its oxide ore through reduction.
Explanation :
Pyrites `(Cu_(2)S)` cannot be reduced by carbon (or) hydrogent because the standard free energy of formation `(DeltaG^(@))` of `Cu_(2)S`is greater then those of `CS_(2)` and `H_(2)S`.
`{:(2Cu_(2)S+Crarr4Cu+CS_(2)),(Cu_(2)S+H_(2)rarrCu+H_(2)S):}}" Not feasible"`
`rarr` The `DeltaG^(@)` of copper oxide is less than that of `CO_(2)`.
`therefore`The sulphide ore is first converted to oxide by roasting and then reduced.
`2Cu_(2)S+3O_(2)underset("heat")overset("Roasting")rarr2Cu_(2)O+2SO_(2)`
`2Cu_(2)O+Crarr4Cu+CO_(2)["feasible"]`.