Difficulty: Easy
Correct Answer: All of the statements (a), (b) and (c) are correct.
Explanation:
Introduction / Context:
Chromite refractories (based on FeO·Cr2O3 spinel compositions) are widely used in metallurgical furnaces where a neutral-to-basic refractory is advantageous. Their behavior against thermal cycling and basic slags influences lining life in steel and nonferrous operations.
Given Data / Assumptions:
Concept / Approach:
Chromite (especially low-silica grades) exhibits good resistance to basic slags and thermal shock/fatigue relative to some silica and magnesite products in specific operating windows. Traditional manufacturing used lime/clay bonding; modern products may use synthetic spinel or resin bonds, but the statement remains broadly correct in a classical context.
Step-by-Step Solution:
Verification / Alternative check:
Handbooks on refractories list chromite as neutral-basic refractory with the cited properties and bonding systems, supporting the combined statement.
Why Other Options Are Wrong:
Common Pitfalls:
Assuming all magnesite bricks outperform chromite in every respect; resistance comparisons depend on grade, impurities, and operating environment.
Final Answer:
All of the statements (a), (b) and (c) are correct.
Discussion & Comments