Addition of zircon to silica refractory brick improves 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. 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

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

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

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

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

6. Sillimanite (Al2O3.SiO2) refractory, which is a neutral refractory, is not used in________________?

   A. Pottery furnace
   B. Glass melting furnace
   C. Crucibles
   D. Gas retorts

7. Zircon refractories have__________________?

   A. Low co-efficient of expansion
   B. High RUL (1600°C) and refractoriness (> 2000°C)
   C. High spalling resistance
   D. All A., B. and C.

8. 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.

9. 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.

10. 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.