Question

Which among the following processes occurs at 1500 K in a blast furnace for extraction of iron?

• A. Reduction of ore
• B. Ore loses moisture
• C. Combustion of coke
• D. Slag formation

Hint:

Slag formation occurs in the hottest region of the blast furnace where molten materials can react and separate easily.

Answer 1

The Correct Option is D

Step 1: Temperature zones in a blast furnace.
A blast furnace has different temperature zones. The upper zone is cooler, while the lower zone reaches very high temperatures (around 1500 K or more). Different chemical processes occur at different temperature levels.

Step 2: Processes occurring at various temperatures.
Loss of moisture from the ore occurs at lower temperatures.
Reduction of iron oxides mainly occurs in the middle zone.
Combustion of coke occurs at very high temperatures near the tuyeres.

Step 3: Slag formation.
At around 1500 K, limestone decomposes to calcium oxide, which reacts with silica impurities to form molten slag: \[ \text{CaO} + \text{SiO}_2 \rightarrow \text{CaSiO}_3 \]

Step 4: Conclusion.
Slag formation takes place at about 1500 K in the blast furnace.