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  • Question
  • Which is the stable form of silica below 870°C?


  • Options
  • A. Tridymite
  • B. Cristobalite
  • C. Quartz
  • D. None of these

  • Correct Answer
  • Quartz 


  • Refractory Technology problems


    Search Results


    • 1. Chemically, mullite refractories is

    • Options
    • A. 3Al2O3.2SiO2
    • B. Al2O3
    • C. ZrSO4
    • D. ThO2
    • Discuss
    • 2. Refractoriness of a typical silica brick corresponds to Segar cone number, '32', which is equivalent to a temperature of __________ °C.

    • Options
    • A. 1380
    • B. 1520
    • C. 1710
    • D. 1915
    • Discuss
    • 3. Thoria is an expensive refractory material and is radioactive in nature. Thorium oxide is used in the manufacture of

    • Options
    • A. segar cones.
    • B. muffles for muffle furnaces.
    • C. insulating bricks.
    • D. crucibles used for melting of high purity metals.
    • Discuss
    • 4. Tarapur atomic power station

    • Options
    • A. has two boiling water reactors of American design.
    • B. has an installed capacity of 400 MW.
    • C. is the first power reactor in India, which became critical in 1969.
    • D. all (a), (b) and (c).
    • Discuss
    • 5. The type of pump used for the recirculation of molten sodium coolant in liquid metal cooled reactor is a/an __________ pump.

    • Options
    • A. electromagnetic
    • B. reciprocating
    • C. centrifugal
    • D. volute
    • Discuss
    • 6. Firing of refractory brick is done to

    • Options
    • A. dehydrate the dried refractory.
    • B. develop stable mineral forms in them.
    • C. form ceramic bonds necessary for development of high crushing strength in the finished product.
    • D. all (a), (b) and (c).
    • Discuss
    • 7. Maximum alumina content in high alumina refractory can be as high as __________ percent.

    • Options
    • A. 30
    • B. 50
    • C. 70
    • D. 90
    • Discuss
    • 8. Spalling of silica bricks occurs due to abrupt volume changes, when it is cooled below a temperature of __________ °C.

    • Options
    • A. 770
    • B. 570
    • C. 270
    • D. 70
    • Discuss
    • 9. Firing temperature of magnesite bricks is about __________ °C.

    • Options
    • A. 800-1000
    • B. 1000-1200
    • C. 1600-1800
    • D. 2400-2600
    • Discuss
    • 10. Fireclay bricks are used in the

    • Options
    • A. coke ovens regenerator.
    • B. outer lining of L.D. converter.
    • C. hearth bottom of blast furnace.
    • D. coke oven walls.
    • Discuss


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