A. Not required to resist the corrosive action of basic slag
B. Not subjected to fluctuation in temperature
C. Used for raising & maintaining high temperature
D. Both B. and C.
Related Mcqs:
- 10 to 30% magnesite is added to Chromite to produce chrome-magnesite refractories. Magnesite addition is mainly done to improve the _____________ of Chromite?
A. Spalling resistance
B. Refractoriness
C. Crushing strength
D. Resistance to slag - Magnesite bricks are used in those parts of furnaces, which are __________________?
A. Subjected to temperature fluctuation
B. Required to resist corrosive basic slag
C. Subjected to high load
D. None of these - Magnesite refractories are generally not used in the___________________?
A. Electric furnace walls
B. Steel melting furnace
C. Open hearth furnace
D. Burning zone of cement kilns - Magnesite refractories have low resistance to___________________?
A. Attack by basic slag
B. Abrasion
C. Disintegration on sudden change of temperature
D. Both B. and C. - Faster rate of drying of moulded refractories results in high _____________ of refractories?
A. Green strength
B. Voids
C. Shrinkage
D. Both B. and C. - Which of the following impurities reduces the refractoriness of magnesite bricks ?
A. Al2O3
B. CaO
C. SiO2
D. All A., B. & C. - Firing temperature of magnesite bricks is about _____________ °C?
A. 800-1000
B. 1000-1200
C. 1600-1800
D. 2400-2600 - Maximum apparent porosity of magnesite bricks is about _____________ percent?
A. 8
B. 24
C. 44
D. 58 - Magnesite chrome refractories____________________?
A. Have better spalling resistance than chrome magnesite refractories
B. Have very low thermal co-efficient of expansion
C. Are not at all resistant to the corrosive action of iron oxide
D. Have very low (50 kg/cm2) cold crushing strength (C.C.S.), and cannot be used in metalcase
form - Magnesite bricks have poor resistance to attack by _____________ slag?
A. Lime
B. Basic
C. Acid
D. None of these
