What is the slag formed from `P_2O_5` impurity in metallurgy of iron?

Options

A. `Ca_3(PO_4)_2`
B. `CaSiO_3`
C. `Fe_3(PO_4)_2`
D. `FeSiO_3`

Answer

To determine the slag formed from the `P2O5` impurity in the metallurgy of iron, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Impurity**: The impurity in question is `P2O5`, which is phosphorus pentoxide. In metallurgy, impurities need to be removed to obtain pure metal.

**Hint**: Remember that impurities can be acidic or basic in nature, which influences the choice of flux.

2. **Understand the Nature of the Impurity**: `P2O5` is acidic in nature. This means that when we are dealing with this impurity, we need to use a basic flux to react with it.

**Hint**: Acidic impurities require basic fluxes for slag formation.

3. **Choose the Appropriate Flux**: The basic flux that is commonly used in the presence of acidic impurities like `P2O5` is calcium oxide (CaO).

**Hint**: Basic fluxes neutralize acidic impurities to form slag.

4. **Reaction Between Impurity and Flux**: When `P2O5` reacts with calcium oxide (CaO), a compound is formed. The reaction can be represented as:
\[ P_2O_5 + CaO \rightarrow Ca_3(PO_4)_2 \]
However, the specific slag formed in this case is often represented as `Ca2PO4H`, which indicates the formation of a phosphate compound.

**Hint**: The stoichiometry of the reaction may vary, but the key is to recognize the formation of a phosphate slag.

5. **Write the Formula of the Slag**: The formula of the slag formed from the reaction of `P2O5` with calcium oxide is `Ca3(PO4)2`, which can also be represented as `Ca2PO4H` depending on the conditions of the reaction.

**Hint**: Pay attention to the valency of calcium and phosphate ions when writing the formula.

### Final Answer:
The slag formed from the `P2O5` impurity in metallurgy of iron is `Ca3(PO4)2` or `Ca2PO4H`.