In the extraction process of copper, the product obtained after carrying out the reactions

$\text{ (i) }2{\mathrm{Cu}}_2 \mathrm{S}+3{\mathrm{O}}_2⟶2{\mathrm{Cu}}_2\mathrm{O}+2{\mathrm{SO}}_2$

$\text{ (ii) }2{\mathrm{Cu}}_2\mathrm{O}+{\mathrm{Cu}}_2 \mathrm{S}⟶6\mathrm{Cu}+{\mathrm{SO}}_2$ is called

The copper(I) sulphide produced is converted to copper with a final blast of air. The end product of this is called blister copper - a porous brittle form of copper, about $98 - 99.5\%$ pure. The reactions given are carried out in the production of blister copper using self reduction.