A. Are not resistant to the action of basic slags
B. Combine with salts (e.g. chlorides sulphates etc.) & bases (e.g. lime, magnesia etc.) forming
fusible aluminates silicates etc
C. Shrink during firing
D. All A., B. and C.
Related Mcqs:
- Magnesite chrome refractories____________________?
A. Have better spalling resistance than chrome magnesite refractories
B. Have very low thermal co-efficient of expansion
C. Are not at all resistant to the corrosive action of iron oxide
D. Have very low (50 kg/cm2) cold crushing strength (C.C.S.), and cannot be used in metalcase
form - Fireclay bricks are never used in the______________?
A. Beehive oven
B. Coke oven walls
C. Zinc roaster
D. Lead blast furnace - Fireclay bricks are used in the___________________?
A. Furnaces allowed to cool frequently
B. Flues
C. Chimney linings
D. All A., B. and C. - Cold crushing strength of fireclay bricks is about ______________ kgf/cm2?
A. 50-100
B. 100-150
C. 200-400
D. 500-1000 - . Refractoriness under load (RUL) of fireclay bricks (under a load of 2 kg/cm2) is ______________ °C?
A. 500
B. 1000
C. >1350
D. >2000 - Maximum safe working temperature for fireclay bricks is about __________ °C?
A. 1150
B. 1300
C. 1450
D. 1550 - Fireclay refractories have __________________?
A. Low co-efficient of thermal expansion
B. Poor thermal spalling resistance
C. Tendency to expand unduly high during firing
D. Very high cost - Colour of fireclay bricks is_________________?
A. Light buff to reddish buff
B. Yellow
C. Black
D. None of these - Porosity of fireclay refractories is _______________ percent?
A. 5-10
B. 10-25
C. 25-35
D. 35-50 - Fireclay bricks are used in the__________________?
A. Coke ovens regenerator
B. Outer lining of L.D. converter
C. Hearth bottom of blast furnace
D. Coke oven walls
