Use of higher percentage of lime for bonding silica bricks, reduces their__________________?

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. 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

3. Porosity of silica bricks varies from ______________ percent?

   A. 5 to 10
   B. 20 to 30
   C. 45 to 60
   D. 60 to 75

4. Silica bricks have low spalling resistance below 600°C, due to its________________?

   A. Very high thermal conductivity
   B. High co-efficient of expansion upto this temperature
   C. High thermal diffusivity
   D. Low refractoriness

5. The maximum linear expansion of silica bricks during firing is about ______________ percent?

   A. 0.5
   B. 1
   C. 2
   D. 3.5

6. 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

7. Which of the following impurities reduces the refractoriness of magnesite bricks ?

   A. Al2O3
   B. CaO
   C. SiO2
   D. All A., B. & C.

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

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

9. Dry mix hydraulic compositions of refractory aggregates with suitable bonding materials are called refractory_________________?

   A. Mortars
   B. Cements
   C. Castables
   D. None of these

10. 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