chemical engineering refractory technology MCQs – Page 2

Practise multiple-choice questions from chemical engineering refractory technology for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering refractory technology Mcqs
21. Which of the following consumes the maximum tonnage of refractories annually in an integrated steel plant ?
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A. Reheating furnace

B. Soaking pits

C. Rotary lime kiln

D. L.D. converter
22. . Refractoriness under load (RUL) of fireclay bricks (under a load of 2 kg/cm2) is ______________ C?
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A. >2000

B. >1350

C. 500

D. 1000

23. Machine moulding of dry mixture of refractories requires a pressure of the order of _____________ kg/cm2?
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A. 1000

B. 10

C. 500

D. 100

24. Panel test determines the _____________ of refractories?
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A. Fusion point

B. Refractoriness under load (RUL)

C. Slag penetration resistance

D. Spalling resistance
25. Thoria__________________?
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A. Has high resistance to basic slags

B. All A., B. and C.

C. Which is expensive & radioactive, is used in crucibles for melting high purity metals

D. Has high fusion temperature (> 3000C) but poor resistance to thermal shock

26. Chrome magnesite bricks are_________________?
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A. Having higher RUL than silica bricks

B. Neutral in nature

C. Made by mixing 30% Chromite and 70% Periclase

D. Acidic in nature

27. Spray test determines the _____________ of refractories?
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A. Resistance to CO attack

B. Permanent linear change

C. RUL

D. Resistance to slag penetration
28. Which brick undergoes maximum shrinkage on drying ?
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A. Magnesite bricks

B. Fireclay bricks

C. Chromite bricks

D. Tar bonded dolomite bricks

29. High density refractory bricks have lower__________________?
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A. Spalling resistance

B. Slag penetration resistance

C. Fusion point

D. Thermal conductivity

30. Magnesite bricks are used in those parts of furnaces, which are __________________?
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A. Subjected to temperature fluctuation

B. Required to resist corrosive basic slag

C. None of these

D. Subjected to high load

31. Refractories are dried in the _______________?
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A. None of these

B. Sun

C. Rotary kilns

D. Tunnel kilns
32. Conversion of silica mineral to Cristobalite is accompanied by reduction in its ____________________?
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A. Volume

B. Specific gravity

C. Both A. & B.

D. Neither A. nor B.

33. Test piece for determination of RUL of a refractory is heated in a/an____________________?
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A. Oxidising atmosphere

B. Electric furnace

C. Reducing atmosphere

D. Neutral atmosphere

34. Spalling of a refractory means its____________________?
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A. Softening

B. Fracture due to uneven expansion at high temperature

C. Resistance to compressive loads

D. Resistance to chemical action of gases and molten fluxes

35. Porosity of silica bricks varies from ______________ percent?
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A. 5 to 10

B. 20 to 30

C. 60 to 75

D. 45 to 60

36. Fireclay refractories have __________________?
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A. Poor thermal spalling resistance

B. Very high cost

C. Tendency to expand unduly high during firing

D. Low co-efficient of thermal expansion
37. Ganister is a source of the ________________?
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A. Lime

B. Silica

C. Periclase

D. None of these

38. Refractoriness/fusion points of Superduty refractories is _______________ C?
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A. > 1730

B. > 2000

C. 1630-1670

D. 1520-1630

39. Which is the most stable crystalline form of silica at room temperature ?
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A. Cristobalite

B. None of these

C. Tridymite

D. Quartz
40. Chromite refractories_____________________?
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A. Are bonded with lime and clay

B. All A., B. and C.

C. (Free from silica) have better thermal fatigue resistance than silica and magnesite refractories.

D. Are resistant to basic slag