In the extraction process of copper, the product obtained after carrying out the reactions
(i) \( 2\mathrm{Cu_2S} + 3\mathrm{O_2} \rightarrow 2\mathrm{Cu_2O} + 2\mathrm{SO_2} \) (ii) \( 2\mathrm{Cu_2O} + \mathrm{Cu_2S} \rightarrow 6\mathrm{Cu} + \mathrm{SO_2} \)
is called:
