In the metallurgy of iron, the slag is

Options

A. `FeSiO_3`
B. `CaCO_3`
C. `CaSiO_3`
D. CaO

Answer

### Step-by-Step Text Solution:

1. **Understanding the Context**: In metallurgy, particularly in the extraction of metals like iron, various processes are employed to purify the metal from its ore. One of the by-products of these processes is known as slag.

2. **Role of Flux**: During the extraction of iron, a substance called calcium carbonate (CaCO3) is used as a flux. A flux is a material that helps to lower the melting point of the ore and facilitates the removal of impurities.

3. **Chemical Reaction**: When calcium carbonate is heated, it decomposes into calcium oxide (CaO) and carbon dioxide (CO2):
\[ \text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2 \]

4. **Formation of Slag**: The calcium oxide produced reacts with silicon dioxide (SiO2), which is also present in the ore. This reaction forms calcium silicate (CaSiO3), which is the slag:
\[ \text{CaO} + \text{SiO}_2 \rightarrow \text{CaSiO}_3 \]

5. **Characteristics of Slag**: The slag (CaSiO3) is a glass-like product that is formed as a by-product after the desired metal (in this case, iron) has been separated from its ore. It is typically a mixture of metal oxides and is often discarded after the extraction process.

6. **Conclusion**: Therefore, in the metallurgy of iron, the slag is primarily calcium silicate (CaSiO3), which is produced from the reaction of calcium oxide and silicon dioxide.

### Final Answer:
In the metallurgy of iron, the slag is calcium silicate (CaSiO3), a glass-like product formed during the purification process.

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