Fireclay refractories___________________? 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 firingD. All A., B. and C.

Silica bricks are never used for lining the_________________? A. Beehive coke ovens B. By-product coke ovens C. Dome of blast furnace stoves D. Roof of open hearth furnace

Refractory bricks having lower porosity have _____________________? A. High insulating properties B. Low heat capacity C. Low thermal conductivityD. Greater strength

Ceramic recuperators used for waste heat recovery from high temperature flue gas going out of the furnace is made of ________________? A. FireclayB. Silicon carbide C. Corundum D. Siliceous fireclay

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

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°CD. All A., B. and C.

With increase in the porosity, thermal spalling resistance of fireclay brick_______________? A. Increases B. Decreases C. Remain same D. May increase or decrease

Refractoriness/fusion points of ‘Superduty’ refractories is _____________ °C? A. 1520-1630 B. 1630-1670C. > 1730 D. > 2000

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