The smelting of iron in a blast furance involves all the steps except

Options

A. Reduction
B. Fusion
C. Sublimation
D. Decomposition

Answer

To solve the question regarding the smelting of iron in a blast furnace and identify which steps are not involved, we can break down the process step by step.

### Step 1: Understand the Process of Smelting
Smelting is the process of extracting a metal from its oxide or other compounds by heating and melting. In the case of iron, iron oxide (Fe2O3) is reduced to iron (Fe).

**Hint:** Smelting involves converting metal oxides into metals through reduction.

### Step 2: Identify the Main Steps in Iron Smelting
1. **Calcination**: Iron oxide (Fe2O3) is first converted to iron(II,III) oxide (Fe3O4) by heating.
2. **Reduction**: At high temperatures, Fe3O4 is reduced to iron (Fe) using carbon monoxide (CO) as a reducing agent.
3. **Formation of Slag**: Calcium carbonate (CaCO3) decomposes to calcium oxide (CaO) and carbon dioxide (CO2). CaO then reacts with silica (SiO2) to form slag (CaSiO3).
4. **Reduction of Iron Oxide**: The remaining iron oxide is reduced to iron using carbon.

**Hint:** The main steps include calcination, reduction, and slag formation.

### Step 3: Analyze the Options
The question asks which steps are **not** involved in the smelting process. The options mentioned are:
1. Reduction
2. Fusion
3. Sublimation
4. Decomposition

- **Reduction** is a key step in smelting, so it is involved.
- **Fusion** refers to the process where two different nuclei combine to form a new nucleus, which does not occur in the smelting of iron.
- **Sublimation** is the direct conversion of a solid to a gas without passing through a liquid state, which is also not part of the smelting process.
- **Decomposition** occurs when calcium carbonate breaks down into calcium oxide and carbon dioxide, which is involved in the process.

**Hint:** Identify which processes are fundamental to smelting and which are not.

### Step 4: Conclusion
The steps that are **not** involved in the smelting of iron in a blast furnace are:
- **Fusion**
- **Sublimation**

Thus, the correct answer is that the smelting of iron involves all the steps except fusion and sublimation.

**Final Answer:** Fusion and sublimation are the steps not involved in the smelting of iron in a blast furnace.