chemical engineering refractory technology MCQs – Page 3

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 Review each marked answer and report any item that may be outdated or unclear.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
41. With increase in the porosity, thermal spalling resistance of fireclay brick___________________?
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A. Increases

B. Decreases

C. Remain same

D. May increase or decrease

42. Magnesite refractories are generally not used in the___________________?
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A. Open hearth furnace

B. Burning zone of cement kilns

C. Steel melting furnace

D. Electric furnace walls

43. Sillimanite is a _____________ refractory?
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A. Basic

B. Neutral

C. Insulating

D. High alumina
44. Roof of a basic open hearth furnace is lined with ______________ bricks?
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A. Dolomite

B. Silica

C. Magnesite

D. Fireclay

45. Dry mix hydraulic compositions of refractory aggregates with suitable bonding materials are called refractory_________________?
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A. None of these

B. Mortars

C. Castables

D. Cements

46. With increase in the density of silica refractories, its_______________?
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A. Resistance to slag attack increases

B. Spalling resistance reduces

C. Both A. and B.

D. Neither A. nor B.

47. Which furnace consumes maximum refractory annually in an integrated steel plant ?
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A. Soaking pit

B. Blast furnace

C. Coke ovens

D. L.D. converter
48. Silica refractories are not used in _________________?
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A. Beehive coke ovens

B. Dome and upper portion of B.F. stoves

C. Open hearth furnace roof

D. Coke oven walls

49. 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 ?
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A. 1800

B. 2700

C. 2200

D. 2400

50. Silica refractories__________________?
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A. crack when subjected to sudden change of temperature

B. All A., B. and C.

C. Have lower thermal conductivity than fireclay bricks

D. Cannot be used in the dome of hot blast stoves

51. Firing temperature is minimum (1250-1400 C) for _______________ bricks?
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A. Fireclay

B. Silica

C. Direct bonded basic

D. Magnesite

52. Ramming masses are used for____________________?
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A. Obtaining monolithic working faces

B. Repairing construction of various furnace parts

C. Both A. & B.

D. Neither A. nor B.

53. Which is the stable form of silica upto 1470C ?
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A. None of these

B. Quartz

C. Cristobalite

D. Tridymite
54. Carbon refractories have very high __________________?
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A. Wetting characteristics

B. Refractoriness

C. Thermal conductivity

D. Both B. and C.
55. Alumina-graphite bricks are used for lining the ____________________?
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A. Slide gate in teeming laddies

B. Continuous casting systems

C. Both A. and B.

D. Neither A. nor B.

56. Maximum safe working temperature for fireclay bricks is about __________ C?
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A. 1450

B. 1550

C. 1150

D. 1300

57. The highest melting pure oxide (m.p. > 3000C)is___________________?
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A. Zirconia

B. Beryllia

C. Thoria

D. Alumina

58. Walls, roofs & combustion chambers of annealing furnaces are made of ______________ bricks?
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A. Carborundum

B. Mullite

C. High duty fireclay

D. Silica

59. _____________ nozzles are used in continuous casting of steel?
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A. Carborundum

B. Thoria

C. Beryllia

D. Zircon
60. Hot face insulating linings of high purity alumina fused mullite are used, where_________________?
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A. Presence of iron or silica is harmful

B. Very high temperatures are involved

C. All A., B. and C.

D. Highly reducing conditions are involved