An ideal refractory should have high__________________? A. Spalling rateB. Fusion point C. Shrinkage ability D. None of these

Carbon refractories have very high __________________? A. Wetting characteristics B. Refractoriness C. Thermal conductivityD. Both B. and C.

Zirconia refractory_________________? A. Does not react with basic slagsB. Is produced from baddeleyite C. Cannot be used as an insulator D. Has poor electrical conductivity at high temperature

Graphite or carbon refractories______________________? A. Exhibit wetting characteristicsB. Should be used in neutral or reducing atmosphere C. Exhibit high shrinkage on thermal treatment D. Are not resistant to corrosion by slag

Refractory materials are never used in the construction of _________________? A. Segar cones B. Orton conesC. Pressure vessels D. Ovens & retorts

Chrome magnesite bricks are used in the_________________? A. Side walls of soaking pits and arc furnaces B. Copper melting furnaces & converters C. Burner block of glass tanksD. All A., B. and C.

Roof of a basic open hearth furnace is lined with ______________ bricks? A. Silica B. Fireclay C. Dolomite D. Magnesite

Which of the following bricks has the most close values of RUL and PCE ? A. Silica bricks B. Fireclay bricks C. High alumina bricks D. Tar dolomite bricks

Which is the most stable crystalline form of silica at room temperature ? A. Quartz B. Cristobalite C. Tridymite D. None of these

Because of its very high refractoriness of the order of __________ °C, silicon carbide refractories are used in zinc smelting furnace, muffle furnace and for supporting the wares in tunnel kilns ? A. 1800 B. 2200 C. 2400D. 2700