Extraction of copper is done using copper pyrites. After roasting, the ore is mixed with silica and coke and then smelted in a blast furnace. The matte obtained from the blast furnace is charged into a silica-lined converter. Some silica is also added, and a hot air blast is blown into the mixture to obtain blister copper, which is purified by electrorefining.
The chemical composition of the slag formed during smelting is.

Options

A. `CuSiO_(3)`
B. `FeSiO_(3)`
C. `CaSiO_(3)`
D. `Cu_(2)O. SiO_(2)`

Explanation

To determine the chemical composition of the slag formed during the smelting of copper pyrites, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Smelting Process**:
- Smelting involves heating the ore (in this case, copper pyrites) with a reducing agent (coke) and a flux (silica) in a blast furnace. The purpose of the flux is to combine with impurities to form slag.

2. **Identifying the Components**:
- Copper pyrites (CuFeS2) is roasted to convert it into copper(I) sulfide (Cu2S) and iron oxides (FeO). During smelting, silica (SiO2) is added to react with the iron oxide.

3. **Chemical Reactions**:
- The primary reaction during smelting can be represented as follows:
\[ \text{FeO} + \text{SiO}_2 \rightarrow \text{FeSiO}_3 \]
- Here, iron oxide (FeO) reacts with silica (SiO2) to produce iron silicate, which is the slag.

4. **Analyzing the Options**:
- Given the options:
1. CuSiO3
2. FeSiO3
3. CaSiO3
4. Cu2O.SiO2
- From the reaction identified, the slag formed is primarily iron silicate, which corresponds to option 2: FeSiO3.

5. **Conclusion**:
- Therefore, the chemical composition of the slag formed during the smelting of copper pyrites is **FeSiO3**.

### Final Answer:
The chemical composition of the slag formed during smelting is **FeSiO3**.

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