Which brick undergoes maximum shrinkage on drying ?

Related Mcqs:

1. Maximum shrinkage in volume occurring during burning/firing of dried refractories may be as high as ______________ percent?

   A. 10
   B. 15
   C. 20
   D. 30

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. Grog addition in fireclay during brick manufacture is done to_________________?

   A. Reduce its shrinkage on heating
   B. Impart greater spalling resistance
   C. Enhance the strength of fired refractories
   D. All A., B. and C.

4. Firing of refractory brick is done to __________________?

   A. Dehydrate the dried refractory
   B. Develop stable mineral forms in them
   C. Form ceramic bonds necessary for development of high crushing strength in the finished
   product
   D. All A., B. and C.

5. 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

6. An indication of degree of firing in silica brick is its____________________?

   A. Specific gravity
   B. Fusion point
   C. RUL
   D. None of these

7. Thermal diffusivity of a refractory brick is high, when its ____________ is high?

   A. Density
   B. Specific heat
   C. Thermal conductivity
   D. None of these

8. Addition of grog in fireclay brick during its manufacture is advantageous, because it results in_____________________?

   A. Less shrinkage in heating, decreased apparent porosity & increased specific gravity
   B. High strength & thermal spalling resistance
   C. Less addition of water to get a workable plasticity & lesser time required for drying the raw
   refractories and hence increased rate of production
   D. All A., B. and C.

9. Cold crushing strength of ordinary fireclay brick is about 950 kg/cm2. On exposure to a temperature of about 1500°C, its crushing strength may come down to as low as ______________ kg/cm2?

   A. 450
   B. 250
   C. 150
   D. 65

10. 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.