Question

Refractories used in furnaces are required to have

• A. High electrical conductivity
• B. Low melting point
• C. Resistance to high temperature and chemical attack
• D. High thermal expansion

Hint:

Logic Tip: A furnace is just a giant, super-hot cooking pot for chemicals. The pot itself needs to survive the fire without melting down, and it must not dissolve into the chemical soup it is cooking!

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Refractories are materials (usually ceramics) that can withstand very high temperatures without losing their structural integrity or melting. They are used to line furnaces, kilns, and reactors.
Step 2: Key Formula or Approach:
The primary job of a refractory is to act as a heat-resistant barrier.
Step 3: Detailed Explanation:
Refractories must possess:
Thermal Stability: They must not melt or soften at process temperatures (High melting point).
Chemical Inertness: They must resist "chemical attack" from slag, hot gases, and molten metals.
Low Thermal Expansion: High expansion would cause them to crack (spall) when the temperature changes.

Step 4: Final Answer:
Refractories require resistance to high temperatures and chemical attack.