Question

Extraction of copper by smelting uses silica as an additive to remove :

• A. ${Cu_2 S}$
• B. ${FeO}$
• C. ${FeS}$
• D. ${Cu_2O}$

Answer 1

The Correct Option is B

The extraction of copper from its ores by smelting involves a series of steps, including the removal of impurities to obtain pure metal. One of the critical impurities in the ore is iron oxide, FeO, which needs to be removed during the smelting process.

Silica (SiO_2) is added to the smelting process as a flux. The role of the flux is to combine with impurities to form a slag, which can be easily removed from the molten metal. Specifically, silica reacts with iron oxide to form iron silicate, {2FeO + SiO_2 \rightarrow Fe_2SiO_4}, which is a fusible slag.

Explanation of the Process:

1. Copper Extraction: Smelting is a pyrometallurgical process used to produce copper from its sulfide ores.
2. Role of Silica: As mentioned, silica (SiO₂) is used to remove the impurity {FeO} by forming a slag.
3. Chemical Reaction: The reaction between silica and iron oxide to form iron silicate is represented as: {2FeO + SiO_2 \rightarrow Fe_2SiO_4}

Through this reaction, FeO is effectively removed as a slag, leaving behind the purer form of copper metal in the melt. Therefore, among the given options, silica is specifically used to remove {FeO} during the smelting process of copper.

Conclusion:

The correct answer is {FeO}, as it is removed by silica during the smelting of copper.