In the manufacture of iron from hematite, limestone is added to act as _____.

Options

A. Flux
B. slag
C. reducing agent
D. gangue

Explanation

To answer the question regarding the role of limestone in the manufacture of iron from hematite, we can break down the process step by step:

### Step-by-Step Solution:

1. **Understanding the Raw Materials**:
- The primary ore for iron production is hematite, which has the chemical formula Fe₂O₃.

2. **Role of Limestone**:
- Limestone, chemically known as calcium carbonate (CaCO₃), is added during the iron extraction process.

3. **Function of Limestone**:
- The main function of limestone in this context is to act as a flux. A flux is a substance that helps to remove impurities from the ore.

4. **Impurities in Hematite**:
- Hematite often contains impurities such as silica (SiO₂) and alumina (Al₂O₃). These impurities need to be removed to obtain pure iron.

5. **Formation of Slag**:
- When limestone is heated, it decomposes to form lime (CaO) and carbon dioxide (CO₂). The lime then reacts with the impurities present in the iron ore to form slag, which is a molten mixture of impurities.

6. **Removal of Slag**:
- The slag, being less dense than molten iron, floats on the surface and can be easily removed, leaving behind the desired product, pig iron.

7. **Conclusion**:
- Therefore, the correct answer to the question is that limestone is added to act as a flux in the manufacture of iron from hematite.

### Final Answer:
In the manufacture of iron from hematite, limestone is added to act as a **flux**.

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