Chemical Engineering - Refractory Technology

21. 

Maximum shrinkage in volume occurring during burning/firing of dried refractories may be as high as __________ percent.

A. 10
B. 15
C. 20
D. 30

Answer: Option D

Explanation:

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22. 

Porosity of fireclay refractories is __________ percent.

A. 5-10
B. 10-25
C. 25-35
D. 35-50

Answer: Option B

Explanation:

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23. 

SiO2 percentage in firebrick is about

A. 35-40
B. 55-60
C. 80-85
D. >94

Answer: Option B

Explanation:

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24. 

Porosity is induced in insulating refractories by adding

A. powdered naphthalene.
B. ammonium chloride/sulphate.
C. calcium phosphate.
D. all (a), (b) and (c).

Answer: Option D

Explanation:

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25. 

Magnesite bricks have poor resistance to attack by __________ slag.

A. lime
B. basic
C. acid
D. none of these

Answer: Option C

Explanation:

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