Chemical Engineering - Refractory Technology

26. 

Thermal diffusivity of a refractory brick is high, when its __________ is high.

A. density
B. specific heat
C. thermal conductivity
D. none of these

Answer: Option C

Explanation:

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27. 

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 (a), (b) and (c).

Answer: Option D

Explanation:

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28. 

Vacuum steel degassing units are lined with

A. silica bricks
B. low duty firebricks
C. high alumina bricks
D. graphite blocks

Answer: Option C

Explanation:

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29. 

Pyrometric cone equivalent (PCE) value (Segar cone) of 'superduty refractories' is more than 33 which corresponds to a temperature of __________ °C.

A. 1520
B. 1630
C. 1670
D. 1730

Answer: Option D

Explanation:

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30. 

Which is the stable form of silica below 870°C ?

A. Tridymite
B. Cristobalite
C. Quartz
D. None of these

Answer: Option C

Explanation:

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