Question

Which of the following statements is correct regarding the slag obtained during the extraction of iron?

• A. The slag is lighter and has lower melting point than the metal.
• B. The slag is lighter and has higher melting point than the metal.
• C. The slag is heavier and has lower melting point than metal.
• D. The slag is heavier and has higher melting point than the metal.

Hint:

Slag formation: \(CaO + SiO_2 \rightarrow CaSiO_3\). This removes the impurity silica and protects the molten metal from oxidation.

Answer 1

The Correct Option is A

Step 1: Basic Principle
In the blast furnace extraction of iron, slag is formed by the reaction of flux (limestone) with impurities (silica).
Step 2: Solution Procedure:
The slag formed is calcium silicate (\(CaSiO_3\)). It has a lower density than molten iron, so it floats on top of the molten iron, allowing easy separation. It also has a lower melting point than iron, ensuring it remains molten and can be tapped off separately.
Step 3: Required Answer:
The correct statement is that the slag is lighter and has a lower melting point than the metal, option (A).