A. Thoria
B. Alumina
C. Beryllia
D. Zirconia
Related Mcqs:
- Highest melting (m.p = 3070°C) oxide refractory is__________________?
A. Alumina
B. Thoria
C. Zirconia
D. Magnesia - 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 - _____________ is not a single oxide-refractory?
A. Zirconia
B. Silicon carbide
C. Magnesia
D. None of these - Thoria is an expensive refractory material and is radioactive in nature. Thorium oxide is used in the manufacture of______________?
A. Segar cones
B. Muffles for muffle furnaces
C. Insulating bricks
D. Crucibles used for melting of high purity metals - Beryllia (which is used in making crucibles for melting uranium & thorium) is superior to alumina in all respects for high temperature (> 1900°C ) use, except ?
A. Cost
B. Electrical conductivity
C. Thermal conductivity
D. Fusion point - Which is the stable form of silica between 1470°C and the melting point 1713°C ?
A. Cristobalite
B. Tridymite
C. Quartz
D. None of these - Carborundum used for making crucibles for melting non-ferrous metals is chemically________________?
A. Silicon carbide
B. Silicon nitride
C. Crystalline magnesia
D. Zirconium sulphate - Pure bauxite is the best raw material for the manufacture of high alumina refractories, in which maximum alumina content can be as high as _____________ percent?
A. 55
B. 70
C. 80
D. 90 - Fusion temperature of pure silica (SiO2) is _______________ °C?
A. 1350
B. 1715
C. 2570
D. 2800 - 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.
