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.Management Sciences
Category: Refractory Technology
Ceramic recuperators used for waste heat recovery from high temperature flue gas going out of the furnace is made of________________?
0
A. Fireclay
B. Silicon carbide
C. Corundum
D. Siliceous fireclay
With increase in the porosity, thermal spalling resistance of fireclay brick___________________?
A. Increases
B. Decreases
C. Remain same
D. May increase or decrease
Silica refractories__________________?
A. crack when subjected to sudden change of temperature
B. Cannot be used in the dome of hot blast stoves
C. Have lower thermal conductivity than fireclay bricks
D. All A., B. and C.
Carbon refractories have very high __________________?
A. Wetting characteristics
B. Refractoriness
C. Thermal conductivity
D. Both B. and C.
Cermets are combination of ceramic and metallic materials due to which they have high strength & resistance to high temperature. Cermets are used in the_______________?
A. Hearth of the blast furnace
B. Nuclear reactors, missiles & space crafts
C. Insulation of high temperature furnaces
D. Roof of electric furnaces
Machine moulding of dry mixture of refractories requires a pressure of the order of _____________ kg/cm2?
A. 10
B. 100
C. 500
D. 1000
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