Chemical Engineering - Refractory Technology

26. 

Zirconia refractories are not used in

A. making sheaths for thermocouple.
B. lining high temperature ceramic kilns.
C. furnaces subjected to fluctuating temperature.
D. high frequency induction furnaces in the form of inductors.

Answer: Option C

Explanation:

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27. 

Carbon refractories

A. do not burn/oxidise, when exposed to air on heating.
B. are not attacked by slags, as they are not wetted by melts.
C. do not resist temperature fluctuations.
D. have extremely low thermal & electrical conductivities.

Answer: Option B

Explanation:

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28. 

Magnesite refractories have low resistance to

A. attack by basic slag.
B. abrasion.
C. disintegration on sudden change of temperature.
D. both (b) and (c).

Answer: Option D

Explanation:

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29. 

Which property is important for bricks used in the combustion chamber & dome of blast furnace stoves ?

A. High refractoriness.
B. High resistance to spalling.
C. High strength and density.
D. All (a), (b) and (c).

Answer: Option A

Explanation:

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30. 

The maximum linear expansion of silica bricks during firing is about __________ percent.

A. 0.5
B. 1
C. 2
D. 3.5

Answer: Option D

Explanation:

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