What are the characteristic behaviors of magnesite-chrome refractories ____________________?
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Answer: A. Have better spalling resistance than chrome magnesite refractories
Explanation
Magnesite-chrome refractories contain optimized microstructures that accommodate thermal expansion stresses better than chrome-magnesite. This structural modification significantly improves their resistance to thermal spalling during furnace temperature fluctuations. Engineers select magnesite-chrome over chrome-magnesite when operating cycles involve frequent heating and cooling. Magnesite-chrome bricks feature a higher ratio of periclase to chromite compared to chrome-magnesite blends. Thermal spalling resistance prevents bricks from cracking and flaking off during industrial thermal cycling. Microstructural elasticity helps arrest micro-cracks before they propagate through the refractory body.
Batch-operated metallurgical furnaces experience severe thermal cycling that demands spalling-resistant brick linings. Improving spalling resistance extends refractory campaign life and reduces costly production downtime. Understanding compositional differences helps plant engineers select the correct basic brick variety. Option B is wrong because these refractories possess a relatively high thermal coefficient of expansion. Option C is incorrect because magnesite-chrome bricks exhibit strong resistance to iron oxide corrosion. Option D is false because their cold crushing strength is high and they are frequently used in metal cases.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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