Question

The compound(s) that is(are) removed as slag during the extraction of copper is
(A)CaO,(B)FeO,(C)Al₂O₃,(D)ZnO,(E)NiO
Choose the correct answer from the options given below :

• A. (C), (D) only
• B. (A), (B), (E) only
• C. (A), (B) only
• D. (B) only

Answer 1

The Correct Option is D

The process of extracting copper from its ores involves a series of steps, one of which includes the removal of impurities that form slag. During the extraction process, certain metal oxides react with flux to form a fusible slag, which is then removed. Knowing which components form slag in this process helps identify the correct answer.

In the extraction of copper from copper pyrites (CuFeS₂), iron is one of the impurities that needs to be removed. Iron is converted into iron oxide (FeO) during the roasting process. To remove this FeO, silica (SiO₂) is added, which acts as a flux. The silica reacts with FeO to form iron silicate (FeSiO₃), a slag that can be easily removed.

The relevant chemical reaction during this process can be represented as:

\text{FeO} + \text{SiO}_2 \rightarrow \text{FeSiO}_3 \, (\text{slag})

Among the options given:

• (A) CaO: Limestone (CaCO₃) might be added to remove silicon oxides as slag, but it's not relevant here.
• (B) FeO: Removed as slag in the form of iron silicate (FeSiO₃).
• (C) Al₂O₃: Generally does not compose slag in copper extraction from copper pyrites.
• (D) ZnO: Zinc compounds are not present nor targeted for removal as slag in this process.
• (E) NiO: Similar to zinc, nickel compounds are also not present in this slag removal context.

Therefore, only FeO is removed as slag during the extraction of copper in this process.

Conclusion: The correct answer is (B) only.