Porosity of silica bricks varies from ______________ percent?

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

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

3. Maximum apparent porosity of magnesite bricks is about _____________ percent?

   A. 8
   B. 24
   C. 44
   D. 58

4. 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

5. 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

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

   A. Strength
   B. Abrasion resistance
   C. Both A. & B.
   D. Neither A. nor B.

7. 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

8. High porosity refractory bricks have _______________?

   A. Poor resistance to the penetration of molten slag, metal & flue gases
   B. Poor heat conductivity & low strength
   C. Better thermal spalling resistance
   D. All A., B. and C.

9. Refractory bricks having lower porosity have_________________________?

   A. High insulating properties
   B. Low heat capacity
   C. Low thermal conductivity
   D. Greater strength

10. Water content in ground refractory material to be shaped into bricks by hand moulding is about ______________ percent?

    A. 5
    B. 20
    C. 40
    D. 55