Question

The chemical composition of 'slag' formed during the smelting process in the extraction of copper is:

• A. Cu$_2$O + FeS
• B. FeSiO$_3$
• C. CuFeS$_2$
• D. Cu$_2$S + FeO

Hint:

Slag formation is crucial in metallurgy as it helps remove unwanted iron impurities during copper extraction.

Answer 1

The Correct Option is B

Step 1: Copper Smelting Overview
- Copper is extracted from copper pyrites (CuFeS$_2$) using a blast furnace. - Iron, an impurity in the ore, is removed as slag. Step 2: Smelting Chemical Processes 
- Iron sulfide (FeS) is oxidized to iron oxide (FeO): \[ 2FeS + 3O_2 \rightarrow 2FeO + 2SO_2 \] - Iron oxide (FeO) reacts with silica (SiO$_2$) to produce ferrous silicate (FeSiO$_3$), the slag: \[ FeO + SiO_2 \rightarrow FeSiO_3 \] Step 3: Slag's Function 
- Ferrous silicate (FeSiO$_3$) facilitates the removal of iron impurities from molten copper. - The less dense ferrous silicate floats on the molten copper surface, allowing for easy separation. 
Final Answer: Ferrous silicate (FeSiO$_3$) is the resulting slag.