Machine moulding of dry mixture of refractories requires a pressure of the order of _____________ kg/cm2?

A. Buckstay
B. Breast wall
C. Armouring
D. Baffle

A. Do not burn/oxidise, when exposed to air on heating
B. Are not attacked by slags, as they are not wetted by melts
C. Do not resist temperature fluctuations
D. Have extremely low thermal & electrical conductivities

A. Fireclay bricks
B. Mullite bricks
C. Tar dolomite bricks
D. High alumina bricks

A. Green strength
B. Voids
C. Shrinkage
D. Both B. and C.

A. Reduce its shrinkage on heating
B. Impart greater spalling resistance
C. Enhance the strength of fired refractories
D. All A., B. and C.

A. Low co-efficient of thermal expansion
B. Poor thermal spalling resistance
C. Tendency to expand unduly high during firing
D. Very high cost