Refractory Technology MCQ Questions & Answers

71

High porosity refractory bricks have

A) Poor resistance to the peneration of molten slag, metal & flue gases B) Poor heat conductivity & low strength C) Better thermal spalling resistance D) All of the above

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Answer & Solution

Answer: Option D

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72

Which is not a high alumina refractory?

A) Mullite B) Corrundum C) Bauxite D) Dolomite

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Answer & Solution

Answer: Option D

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73

Which of the following has the lowest electrical resistivity?

A) Graphite B) Fireclay C) Alumina D) Zircon

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Answer & Solution

Answer: Option A

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74

Periclase is

A) Crystalline form of MgO B) MgCO₃ C) ZrSO₄ D) Amorphous magnesite

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Answer & Solution

Answer: Option A

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75

Pick out the wrong statement.

A) Refractories used in muffle furnace should have low thermal conductivity B) The electrical resistivity of refractories drops rapidly with rise in temperature C) For reducing spalling tendency, the refractory should be well fired and its porosity should be more D) Refractoriness under load (RUL) of a refractory is always less than its refractoriness

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Answer & Solution

Answer: Option A

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76

Quartz is

A) Stable form of silica upto 870°C B) Converted to tridymite on firing between 870 to 1470°C C) Transformed to crystoballite on heating above 1470°C D) All of the above

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Answer & Solution

Answer: Option D

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77

Refractory castables are used for

A) Producing monolithic linings B) Patch work C) Minimising the number of joints in the structure D) All of the above

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Answer & Solution

Answer: Option D

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78

Silliminite (Al₂O₃.SiO₂) refractory, which is a neutral refractory, is not used in

A) Pottery furnace B) Glass melting furnace C) Crucibles D) Gas retorts

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Answer & Solution

Answer: Option D

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79

Ramming masses are used for

A) Obtaining monolithic working faces B) Repairing construction of various furnace parts C) Both A & B D) Neither A nor B

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Answer & Solution

Answer: Option C

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80

Graphite or carbon refractories

A) Exihibit wetting characteristics B) Should be used in neutral or reducing atmosphere C) Exhibit high shrinkage on thermal treatment D) Are not resistant to corrosion by slag

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Answer & Solution

Answer: Option B

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Refractory Technology MCQ Questions & Answers | Chemical Engineering