‘Spinel’, a refractory mineral is chemically represented as____________________?

Related Mcqs:

1. Mullite is chemically represented by_________________?

   A. Al2O3. 2SiO2
   B. 3Al2O3. 2SiO2
   C. Al2O3. SiO2
   D. 2Al2O3. 3SiO2

2. 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

3. Chemically, mullite refractories is____________________?

   A. 3Al2O3.2SiO2
   B. Al2O3
   C. ZrSO4
   D. ThO2

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

   A. Volume
   B. Specific gravity
   C. Both A. & B.
   D. Neither A. nor B.

5. An ideal refractory should have high__________________?

   A. Spalling rate
   B. Fusion point
   C. Shrinkage ability
   D. None of these

6. Which is required in an insulating refractory ?

   A. High thermal conductivity
   B. Low porosity
   C. Both A. and B.
   D. Neither A. nor B.

7. Which is not a high alumina refractory ?

   A. Mullite
   B. Corundum
   C. Bauxite
   D. Dolomite

8. Cold crushing strength of a refractory does not depend upon its ____________________?

   A. Shape
   B. Composition
   C. Firing temperature
   D. Texture

9. High alumina refractory compared to fireclay bricks have____________________?

   A. Less load bearing capacity
   B. Less resistance to slag attack
   C. Low refractoriness
   D. High resistance to thermal shock and creep

10. Refractory bricks with lower permeability is produced by using __________________?

    A. Higher firing temperature
    B. Higher moulding pressure
    C. Finer grog size
    D. All A., B. and C.