A. Decreased viscosity of slag
B. Increased thermal conductivity of brick
C. Oxidising condition in the furnace
D. None of these
Related Mcqs:
- Faster rate of drying of moulded refractories results in high _____________ of refractories?
A. Green strength
B. Voids
C. Shrinkage
D. Both B. and C. - Resistance to slag attack of a refractory _____________________?
A. Depends on the nature of slag & refractory
B. Decreases at higher temperature
C. Decreases, if defective joints & cracks exist in the refractory
D. All A., B. and C. - Magnesite bricks have poor resistance to attack by _____________ slag?
A. Lime
B. Basic
C. Acid
D. None of these - Magnesite refractories are generally not used in the___________________?
A. Electric furnace walls
B. Steel melting furnace
C. Open hearth furnace
D. Burning zone of cement kilns - 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 - Furnace atmosphere for softening temperature determination of refractories (in which Seger Cones are placed) should be __________________?
A. Oxidising
B. Neutral
C. Either A. or B.
D. Neither A. nor B. - PCE value (Segar cone) of Superduty refractories is more than 33, which is equivalent to a temperature of ____________ °C?
A. 1520
B. 1630
C. 1670
D. 1730 - Except _____________, all other refractories are bad conductors of electricity (i.e, have low electrical conductivity)?
A. Fireclay
B. Carborundum
C. Graphite
D. Chromite - 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 - With decrease in porosity, the ______________ of the refractories decreases?
A. Strength
B. Thermal conductivity
C. Spalling resistance
D. None of these
