Question

_________ is not a neutral refractory.

• A. Zircon
• B. Chrome
• C. Carbon
• D. Silicon carbide

Hint:

Neutral refractories, such as zircon, chromite, and silicon carbide, are stable in both acidic and basic environments. However, carbon-based refractories are basic, not neutral.

Answer 1

The Correct Option is C

Refractory materials are classified into three types based on their chemical behavior: 1. Acidic refractories – Resistant to acidic environments (e.g., silica). 2. Basic refractories – Resistant to basic environments (e.g., magnesite). 3. Neutral refractories – Resistant to both acidic and basic conditions (e.g., chromite, zircon). Step 1: Understanding Neutral Refractories - Zircon (\( ZrSiO_4 \)) is a neutral refractory with high chemical stability. - Chrome refractories (\( Cr_2O_3 \)) are also neutral, commonly used in steel industries. - Silicon carbide (\( SiC \)) is a high-strength neutral refractory with excellent thermal conductivity.

Step 2: Identifying the Non-Neutral Refractory - Carbon (Graphite) is a basic refractory, meaning it is not neutral. - Carbon-based refractories (graphite, coke) are commonly used in basic linings in furnaces.

Step 3: Evaluating the Options - Option (A) - Incorrect: Zircon is a neutral refractory. - Option (B) - Incorrect: Chrome is a neutral refractory. - Option (C) - Correct: Carbon is a basic refractory, not neutral. - Option (D) - Incorrect: Silicon carbide is a neutral refractory.

Step 4: Conclusion Since carbon (graphite) is a basic refractory, not neutral, the correct answer is option (C).