A. Increases
B. Lowers
C. Does not affect
D. Either A. or B.; depends on its quantity
Related Mcqs:
- Which is not an alumino-silicate refractory ?
A. Fireclay bricks
B. Mullite bricks
C. Tar dolomite bricks
D. High alumina bricks - Refractoriness/fusion points of ‘Superduty’ refractories is _______________ °C?
A. 1520-1630
B. 1630-1670
C. > 1730
D. > 2000 - Because of its very high refractoriness of the order of __________ °C, silicon carbide refractories are used in zinc smelting furnace, muffle furnace and for supporting the wares in tunnel kilns ?
A. 1800
B. 2200
C. 2400
D. 2700 - Faster rate of drying of moulded refractories results in high _____________ of refractories?
A. Green strength
B. Voids
C. Shrinkage
D. Both B. and C. - With increase in the alumina content in firebricks, its fusion point (refractoriness) ?
A. Decreases linearly
B. Remains unchanged
C. Increases
D. Decreases - Which of the following impurities reduces the refractoriness of magnesite bricks ?
A. Al2O3
B. CaO
C. SiO2
D. All A., B. & C. - High refractoriness of refractory bricks means, that it has a________________?
A. High spalling resistance
B. Low spalling resistance
C. High resistance to fusion
D. Low porosity - Refractoriness under load (RUL) is the most important property for the refractory bricks_________________?
A. At the hearth bottom of the furnace on which stock is placed
B. Used for furnace insulation
C. Used in the roof of the furnace
D. None of these - . Refractoriness under load (RUL) of fireclay bricks (under a load of 2 kg/cm2) is ______________ °C?
A. 500
B. 1000
C. >1350
D. >2000 - Refractoriness under loads (RUL) is quite close to the fusion temperature (PCE) for _____________ bricks?
A. Fireclay
B. Silica
C. Dolomite
D. Very low alumina
