A. Higher firing temperature
B. Higher moulding pressure
C. Finer grog size
D. All A., B. and C.
Related Mcqs:
- An insulating refractory brick should have high porosity and low thermal conductivity. Which of the following is not used for inducing porosity in the insulating refractory bricks during its manufacture ?
A. Cork
B. Saw dust
C. Sand
D. Chemically prepared foam - Refractory bricks having lower porosity have _____________________?
A. High insulating properties
B. Low heat capacity
C. Low thermal conductivity
D. Greater strength - Permeability of bricks is a measure of the___________________?
A. Refractoriness
B. Melting point
C. Rate at which a fluid will pass through the pores
D. Expansion during heating - 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 - 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. - Lower wall courses of soaking pits are made of _____________ bricks to avoid the action of molten slag & scale?
A. Chrome or magnesite
B. Silicon carbide
C. Silica
D. Low duty fireclay - 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 - 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. - Test piece for determination of RUL of a refractory is heated in a/an__________________?
A. Oxidising atmosphere
B. Reducing atmosphere
C. Electric furnace
D. Neutral atmosphere - Fusion point of a basic refractory material is________________?
A. Reduced by the addition of acid oxides
B. Increased by the addition of acid oxides
C. Not affected by the addition of acid oxides
D. Always less than 1000°C
