Refractory Technology What is Thoria? Which is expensive & radioactive, is used in crucibles for melting high purity metals Thoria Has high resistance to basic slags All of these Thoria Has high fusion temperature (> 3000°C) but poor resistance to thermal shock Which is expensive & radioactive, is used in crucibles for melting high purity metals Thoria Has high resistance to basic slags All of these Thoria Has high fusion temperature (> 3000°C) but poor resistance to thermal shock ANSWER DOWNLOAD EXAMIANS APP
Refractory Technology An indication of degree of firing in silica brick is its Specific gravity None of these RUL Fusion point Specific gravity None of these RUL Fusion point ANSWER DOWNLOAD EXAMIANS APP
Refractory Technology __________ bricks are used in the burning zone of a cement rotary kiln. Fireclay Silicon carbide High alumina Thoria Fireclay Silicon carbide High alumina Thoria ANSWER DOWNLOAD EXAMIANS APP
Refractory Technology Which is the most stable crystalline form of silica at room temperature? Cristobalite None of these Tridymite Quartz Cristobalite None of these Tridymite Quartz ANSWER DOWNLOAD EXAMIANS APP
Refractory Technology Refractoriness/fusion points of 'superduty' refractories is __________ °C. > 1730 1520-1630 1630-1670 > 2000 > 1730 1520-1630 1630-1670 > 2000 ANSWER DOWNLOAD EXAMIANS APP
Refractory Technology With decrease in porosity, the __________ of the refractories decreases. None of these Strength Thermal conductivity Spalling resistance None of these Strength Thermal conductivity Spalling resistance ANSWER DOWNLOAD EXAMIANS APP