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.Management Sciences
Category: Refractory Technology
‘Super refractories’ are made from pure____________________?
0
A. Carbides
B. Oxides
C. Borides
D. Nitrides
With increasing alumina content, the fusion point of high alumina refractories__________________?
A. Increases
B. Decreases
C. Remain constant
D. May increase or decrease; depends on its alumina content
Alumina-graphite bricks are used for lining the ____________________?
A. Slide gate in teeming laddies
B. Continuous casting systems
C. Both A. and B.
D. Neither A. nor B.
Presence of MgO in alumino-silicate refractories _______________ its refractoriness?
A. Increases
B. Lowers
C. Does not affect
D. Either A. or B.; depends on its quantity
Roof of a basic electric furnace is made of _____________ bricks?
A. Superduty fireclay
B. Silica
C. Chromite
D. None of these
Cold crushing strength of a refractory does not depend upon its ____________________?
A. Shape
B. Composition
C. Firing temperature
D. Texture
Maximum water percentage in refractory mix meant for hand moulding may be as high as _____________ percent?
A. 2-3
B. 5-7
C. 7-12
D. 14-20
Fireclay bricks are used in the___________________?
A. Furnaces allowed to cool frequently
B. Flues
C. Chimney linings
D. All A., B. and C.
Which is the most stable crystalline form of silica at room temperature ?
A. Quartz
B. Cristobalite
C. Tridymite
D. None of these
______________ bricks are used in the burning zone of a cement rotary kiln ?
A. High alumina
B. Fireclay
C. Thoria
D. Silicon carbide
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