A. Cork
B. Saw dust
C. Sand
D. Chemically prepared foam
Related Mcqs:
- Thermal diffusivity of a refractory brick is high, when its ______________ is high?
A. Density
B. Specific heat
C. Thermal conductivity
D. None of these - 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. - Refractory bricks having lower porosity have _____________________?
A. High insulating properties
B. Low heat capacity
C. Low thermal conductivity
D. Greater strength - Thermal conductivity of refractory bricks____________________?
A. Increases with decrease in porosity
B. Decreases with decreases in porosity
C. Is independent of its porosity and is maximum for insulating bricks
D. Increases with the amount of air entrapped in pores - Refractories used in/for ______________ should have low thermal conductivity?
A. Coke ovens
B. Insulation
C. Regenerators
D. Muffle furnaces - Capacity of a refractory brick to withstand-sudden changes in temperature is denoted by the property called_________________?
A. Spalling resistance
B. Refractoriness
C. Refractoriness under load (RUL)
D. None of these - 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. - 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. - 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 - With increase in the porosity, thermal spalling resistance of fireclay brick_______________?
A. Increases
B. Decreases
C. Remain same
D. May increase or decrease
