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  • Question
  • Presence of MgO in alumino-silicate refractories __________ its refractoriness.


  • Options
  • A. increases
  • B. lowers
  • C. does not affect
  • D. either (a) or (b); depends on its quantity

  • Correct Answer
  • lowers 


  • Refractory Technology problems


    Search Results


    • 1. Firing temperature is minimum (1250-1400 °C) for __________ bricks.

    • Options
    • A. fireclay
    • B. direct bonded basic
    • C. silica
    • D. magnesite
    • Discuss
    • 2. Fireclay bricks are not used in the

    • Options
    • A. beehive coke oven.
    • B. by-product coke oven walls.
    • C. combustion chamber of B.F. stoves.
    • D. coke oven regenerators.
    • Discuss
    • 3. Which is the stable form of silica between 1470°C and the melting point 1713°C?

    • Options
    • A. Cristobalite
    • B. Tridymite
    • C. Quartz
    • D. None of these
    • Discuss
    • 4. High porosity refractory bricks have

    • Options
    • A. poor resistance to the peneration of molten slag, metal & flue gases.
    • B. poor heat conductivity & low strength.
    • C. better thermal spalling resistance.
    • D. all (a), (b) and (c).
    • Discuss
    • 5. Capacity of a refractory brick to withstand-sudden changes in temperature is denoted by the property called

    • Options
    • A. spalling resistance.
    • B. refractoriness.
    • C. refractoriness under load (RUL).
    • D. none of these.
    • Discuss
    • 6. RUL of refractories depends on the

    • Options
    • A. chemical composition.
    • B. physical structure.
    • C. presence of impurities like iron & alkali.
    • D. all (a), (b) and (c).
    • Discuss
    • 7. Which of these statement is correct?

    • Options
    • A. Conversion of quartz to tridymite is associated with 16% volume increase.
    • B. Conversion of tridymite to crystoballite involves very large expansion in volume.
    • C. both (a) and (b).
    • D. neither (a) nor (b).
    • Discuss
    • 8. Which property of refractories is the most important for top section of the blast furnace?

    • Options
    • A. Resistance to abrasion.
    • B. Resistance to slag peneration.
    • C. Stability of volume at high temperature.
    • D. Resistance to corrosion by slag.
    • Discuss
    • 9. Which is not a basic refractory?

    • Options
    • A. Chrome magnesite
    • B. Magnesite
    • C. Dolomite
    • D. Silicon carbide
    • Discuss
    • 10. Resistance to slag attack of a refractory

    • Options
    • A. depends on the nature of slag & refractory.
    • B. decreases at higher temperature.
    • C. decreases, if defective joints & cracks exist in the refractory.
    • D. all (a), (b) and (c).
    • Discuss


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