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  • Question
  • With increase in the alumina content, the refractoriness of high alumina refractories


  • Options
  • A. increases
  • B. decreases
  • C. remains same
  • D. may increase or decrease

  • Correct Answer
  • increases 


  • Refractory Technology problems


    Search Results


    • 1. Grog

    • Options
    • A. contains both alumina and silica.
    • B. iscrushed firebrick.
    • C. is a non-plastic material.
    • D. all (a), (b) and (c).
    • Discuss
    • 2. A steel member used in the furnace construction to take the thrust of the brickwork is called

    • Options
    • A. buckstay
    • B. breast wall
    • C. armouring
    • D. baffle
    • Discuss
    • 3. Water content in ground refractory material to be shaped into bricks by hand moulding is about __________ percent.

    • Options
    • A. 5
    • B. 20
    • C. 40
    • D. 55
    • Discuss
    • 4. Walls, roofs & combustion chambers of annealing furnaces are made of __________ bricks.

    • Options
    • A. high duty fireclay
    • B. silica
    • C. mullite
    • D. carborundum
    • Discuss
    • 5. Skull is not formed on the carbon blocks in the hearth of a blast furnace, when it becomes cold, becaus of its

    • Options
    • A. non-wetting characteristic.
    • B. high thermal conductivity.
    • C. high crushing strength.
    • D. none of these.
    • Discuss
    • 6. Thermal diffusivity of a refractory brick is high, when its __________ is high.

    • Options
    • A. density
    • B. specific heat
    • C. thermal conductivity
    • D. none of these
    • Discuss
    • 7. An indication of degree of firing in silica brick is its

    • Options
    • A. specific gravity
    • B. fusion point
    • C. RUL
    • D. none of these
    • Discuss
    • 8. Quartz is

    • Options
    • A. stable form of silica upto 870°C.
    • B. converted to tridymite on firing between 870 to 1470°C.
    • C. transformed to crystoballite on heating above 1470°C.
    • D. all (a), (b) and (c).
    • Discuss
    • 9. Thoria

    • Options
    • A. has high fusion temperature (> 3000°C) but poor resistance to thermal shock.
    • B. has high resistance to basic slags.
    • C. which is expensive & radioactive, is used in crucibles for melting high purity metals.
    • D. all (a), (b) and (c).
    • Discuss
    • 10. Pyrometric cone equivalent (PCE) value (Segar cone) of 'superduty refractories' is more than 33 which corresponds to a temperature of __________ °C.

    • Options
    • A. 1520
    • B. 1630
    • C. 1670
    • D. 1730
    • Discuss


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