Refractoriness/fusion points of ‘Superduty’ refractories is _____________ °C?

Related Mcqs:

1. Presence of MgO in alumino-silicate refractories ______________ its refractoriness ?

   A. Increases
   B. Lowers
   C. Does not affect
   D. Either A. or B.; depends on its quantity

2. Faster rate of drying of moulded refractories results in high ______________ of refractories?

   A. Green strength
   B. Voids
   C. Shrinkage
   D. Both B. and C.

3. With increase in the alumina content, the refractoriness of high alumina refractories_________________?

   A. Increases
   B. Decreases
   C. Remain same
   D. May increase or decrease

4. Fusion point of a basic refractory material is________________?

   A. Reduced by the addition of acid oxides
   B. Increased by the addition of acid oxides
   C. Not affected by the addition of acid oxides
   D. Always less than 1000°C

5. 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

6. Refractories subjected to alternate cycles of heating & cooling are liable to loose their resistance to__________________?

   A. Thermal spalling
   B. Slag attack
   C. Fusion under load
   D. CO attack

7. Panel test determines the ______________ of refractories?

   A. Fusion point
   B. Spalling resistance
   C. Slag penetration resistance
   D. Refractoriness under load (RUL)

8. Chemically, mullite refractories is________________?

   A. 3Al2O3.2SiO2
   B. Al2O3
   C. ZrSO4
   D. ThO2

9. Magnesite refractories are used for the construction of those furnaces, which are_______________?

   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.

10. Which property of refractories is the most important for top section of the blast furnace ?

    A. Resistance to abrasion
    B. Resistance to slag penetration
    C. Stability of volume at high temperature

    D. Resistance to corrosion by slag