The smelting of iron in a blast furnace involves, which of the
following process(es)?

Options

A. Combustion
B. Reduction
C. Slag formation
D. sublimation

Explanation

To solve the question regarding the processes involved in the smelting of iron in a blast furnace, we can break it down into several steps:

### Step-by-Step Solution:

1. **Understanding Smelting**:
- Smelting is a metallurgical process used to extract metal from its ore by heating and melting. In the case of iron, it involves the reduction of iron oxides.

2. **Identifying Key Processes**:
- The main processes involved in the smelting of iron in a blast furnace are:
- **Combustion**
- **Reduction**
- **Slag Formation**

3. **Combustion Process**:
- In the blast furnace, carbon (from coke) reacts with oxygen to produce carbon dioxide (CO2), which is an exothermic reaction that provides the necessary heat for the smelting process.
- Reaction:
\[ C + O_2 \rightarrow CO_2 \]

4. **Reduction Process**:
- Iron oxides (like FeO and Fe2O3) are reduced to iron using carbon monoxide (CO), which is produced from the combustion of coke.
- Reaction:
\[ Fe_2O_3 + 3C \rightarrow 2Fe + 3CO \]

5. **Slag Formation**:
- Impurities in the iron ore, such as silica, combine with flux (like limestone) to form slag, which is removed from the furnace.
- Reaction:
\[ CaO + SiO_2 \rightarrow CaSiO_3 \text{ (slag)} \]

6. **Conclusion**:
- The processes involved in the smelting of iron in a blast furnace include combustion, reduction, and slag formation. Sublimation is not a process involved in this context.

### Final Answer:
The smelting of iron in a blast furnace involves:
- Combustion
- Reduction
- Slag Formation