A. Corundum
B. Carborundum
C. Bauxite
D. Periclase
Related Mcqs:
- Silicon carbide refractories have very low ___________________?
A. Refractoriness (< 1700°C)
B. Thermal conductivity
C. Resistance to thermal shock
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. 2400
D. 2700 - Silicon carbide refractories are used in the _____________?
A. Muffle furnace
B. Zinc smelting furnace
C. Ceramic recuperators
D. All A., B. and C. - 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 - Faster rate of drying of moulded refractories results in high _____________ of refractories?
A. Green strength
B. Voids
C. Shrinkage
D. Both B. and C. - 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 - Insulating refractories should have_______________?
A. High porosity
B. Low thermal conductivity
C. Both A. and B.
D. Neither A. not B. - Pyrometric cone equivalent (PCE) value (Segar cone) of ‘Superduty refractories’ is more than 33 which corresponds to a temperature of _____________ °C?
A. 1520
B. 1630
C. 1670
D. 1730 - Magnesite refractories are used for the construction of those furnaces, which are________________?
A. Not required to resist the corrosive action of basic slag
B. Not subjected to fluctuation in temperature
C. Used for raising & maintaining high temperature
D. Both 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
