Conversion of silica mineral to Cristobalite is accompanied by reduction in its ____________________?

Related Mcqs:

1. Semi-silica bricks compared to silica bricks have_______________?

   A. Less fusion point
   B. Better spalling resistance
   C. Both A. and B.
   D. Neither A. not B.

2. Si percentage in silica refractories used in the walls of coke oven is about______________________?

   A. 45
   B. 60
   C. 80
   D. 95

3. Silica bricks are attacked by basic slags at high temperature. Which of the following is not used solely as a binding material ?

   A. Aluminium phosphate
   B. Water
   C. Lime
   D. Plaster of Paris

4. Which is the stable form of silica upto 1470°C ?

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

5. With increase in the density of silica refractories, its_______________?

   A. Resistance to slag attack increases
   B. Spalling resistance reduces
   C. Both A. and B.
   D. Neither A. nor B.

6. Refractoriness of a typical silica brick corresponds to Segar cone number, ’32’, which is equivalent to a temperature of _____________ °C?

   A. 1380
   B. 1520
   C. 1710
   D. 1915

7. Silica refractories are not used in _________________?

   A. Coke oven walls
   B. Beehive coke ovens
   C. Dome and upper portion of B.F. stoves
   D. Open hearth furnace roof

8. Fusion temperature of pure silica (SiO2) is _______________ °C?

   A. 1350
   B. 1715
   C. 2570
   D. 2800

9. Addition of zircon to silica refractory brick improves its_____________________?

   A. Crushing strength
   B. Resistance to slag attack
   C. Both A. and B.
   D. Neither A. nor B.

10. Silica bricks are never used for lining the____________________?

    A. Beehive coke ovens
    B. By-product coke ovens
    C. Dome of blast furnace stoves
    D. Roof of open hearth furnace