Related Questions

Porosity of fireclay refractories is __________ percent.
A 5-10
B 10-25
C 25-35
D 35-50
Fireclay refractories have
A Low co-efficient of thermal expansion
B Poor thermal spalling resistance
C Tendency to expand unduly high during firing
D Very high cost
Faster rate of drying of moulded refractories results in high __________ of refractories.
A Green strength
B Voids
C Shrinkage
D Both B and C
Addition of grog in fireclay brick during its manufacture is advantageous, because it results in
A Less shrinkage in heating, decreased apparent porosity & increased specific gravity
B High strength & thermal spalling resistance
C Less addition of water to get a workable plasticity & lesser time required for drying the raw refractories and hence increased rate of production
D All of the above
Maximum safe working temperature for fireclay bricks is about __________ °C.
A 1150
B 1300
C 1450
D 1550
Fireclay bricks is not used for lining the
A Cupola
B Gas producer
C Bottom of hot metal mixer
D Roof of open hearth furnace
Colour of fireclay bricks is
A Light buff to reddish buff
B Yellow
C Black
D None of these
With increase in the porosity, thermal spalling resistance of fireclay brick
A increases
B decreases
C remains same
D may increase or decrease
Grog addition in fireclay during brick manufacture is done to
A Reduce its shrinkage on heating
B Impart greater spalling resistance
C Enhance the strength of fired refractories
D All of the above
Fireclay bricks are used in the
A Furnaces allowed to cool frequently
B Flues
C Chimney linings
D All of the above

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