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.Management Sciences
Category: Refractory Technology
_____________ is not a single oxide-refractory?
A. Zirconia
B. Silicon carbide
C. Magnesia
D. None of these
Spray test determines the _____________ of refractories?
A. Resistance to slag penetration
B. Resistance to CO attack
C. RUL
D. Permanent linear change
Firing of refractory brick is done to __________________?
A. Dehydrate the dried refractory
B. Develop stable mineral forms in them
C. Form ceramic bonds necessary for development of high crushing strength in the finished
product
D. All A., B. and C.
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
Chrome magnesite is not used in the ____________________?
A. Inner lining of L.D. converter
B. Aluminium melting furnaces
C. Wear out lining of steel melting furnaces
D. All A., and B. and C.
High porosity refractory bricks have _______________?
A. Poor resistance to the penetration of molten slag, metal & flue gases
B. Poor heat conductivity & low strength
C. Better thermal spalling resistance
D. All A., B. and C.
Thermal diffusivity of a refractory brick is high, when its ____________ is high?
A. Density
B. Specific heat
C. Thermal conductivity
D. None of these
Tar bonded dolomite bricks__________________?
A. Are stored under controlled temperature & humidity to avoid hydration
B. Are used in outer lining of L.D. converters
C. Have poorer hydration resistance than pitch bonded bricks
D. All A., B. and C.
Fireclay bricks are not used in the_____________________?
A. Blast furnace
B. Hot blast stove
C. Cupola
D. Wall of coke oven
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