Chemistry - Metallurgy Question with Solution | TestHub

The conversion of $\mathrm{CuFe}{\mathrm{S}}_2$ to pure $\mathrm{Cu}$ involves concentration (froth flotation), roasting, smelting (reduction), Bessemerization (auto-reduction), and refining (electrolytic refining). This sequence clearly includes more than two metallurgical processes.

Explanation:

1. $\mathrm{ZnC}{\mathrm{O}}_3$ (concentrated ore) $\to \mathrm{Zn}$ (impure): This involves calcination ($\mathrm{ZnC}{\mathrm{O}}_3\to \mathrm{ZnO}+\mathrm{C}{\mathrm{O}}_2$) followed by reduction ($\mathrm{ZnO}+\mathrm{C}\to \mathrm{Zn}+\mathrm{CO}$). This is two main processes.

2. $\mathrm{CuFe}{\mathrm{S}}_2\to \mathrm{Cu}$ (pure): This is a multi-step process. It starts with concentration (froth flotation), then roasting ($\mathrm{CuFe}{\mathrm{S}}_2\to \mathrm{C}{\mathrm{u}}_2\mathrm{S}+\mathrm{FeS}+\mathrm{S}{\mathrm{O}}_2$), followed by smelting (reduction in a blast furnace to form matte), Bessemerization (auto-reduction of $\mathrm{C}{\mathrm{u}}_2\mathrm{S}$ to blister copper), and finally refining (e.g., electrolytic refining for pure copper). This involves more than two processes.

3. $\mathrm{PbS}$ (roasted ore) $\to \mathrm{Pb}$ (impure): Roasted $\mathrm{PbS}$ (which is $\mathrm{PbO}$ and $\mathrm{PbS}{\mathrm{O}}_4$) undergoes auto-reduction with unroasted $\mathrm{PbS}$ or reduction with carbon. This is primarily one or two main reduction steps.

Therefore, the conversion of $\mathrm{CuFe}{\mathrm{S}}_2$ to pure $\mathrm{Cu}$ involves more than two metallurgical processes.