Ceramic recuperators used for waste heat recovery from high temperature flue gas going out of the furnace is made of ________________?

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

Refractoriness/fusion points of ‘Superduty’ refractories is _____________ °C?

A. 1520-1630

B. 1630-1670

C. > 1730

D. > 2000

With increase in the porosity, thermal spalling resistance of fireclay brick_______________?

A. Increases

B. Decreases

C. Remain same

D. May increase or decrease

Quartz is__________________?

A. Stable form of silica upto 870°C

B. Converted to Tridymite on firing between 870 to 1470°C

C. Transformed to Cristobalite on heating above 1470°C

D. All A., B. and C.

Pure oxide refractories are generally monocrystalline in nature and are self bonded ______________ bricks are generally used as moderator in nuclear reactors?

A. Beryllia

B. Carborundum

C. Corundum

D. Thoria