chemical engineering refractory technology MCQs – Page 7

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 Review each marked answer and report any item that may be outdated or unclear.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
121. Grog addition in fireclay during brick manufacture is done to_________________?
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A. Impart greater spalling resistance

B. All A., B. and C.

C. Enhance the strength of fired refractories

D. Reduce its shrinkage on heating

122. Outer combustion chamber of blast furnace stove is lined with _____________ bricks?
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A. Chrome magnesite

B. Silica

C. Zirconia

D. Fireclay
123. Spinel, a refractory mineral is chemically represented as____________________?
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A. MgAl2O3

B. MgAl2O3.2H2O

C. MgAl2O4

D. MgSO4

124. High alumina refractories are used in the ___________________?
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A. Electric arc furnace roof

B. All A., B. and C.

C. Glass melting furnaces

D. Dome of blast furnace stoves

125. Cermets are____________________?
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A. Composite material containing both ceramic & metallic constituents

B. Having high strength & resistance to high temperature

C. Used in space vehicles, missiles & nuclear energy plants

D. All A., B. and C.
126. Fireclay bricks are used in the___________________?
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A. All A., B. and C.

B. Furnaces allowed to cool frequently

C. Chimney linings

D. Flues

127. Water content in ground refractory material to be shaped into bricks by hand moulding is about ______________ percent?
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A. 55

B. 5

C. 20

D. 40

128. Addition of grog in fireclay brick during its manufacture is advantageous, because it results in_____________________?
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A. Less shrinkage in heating, decreased apparent porosity & increased specific gravity

B. Less addition of water to get a workable plasticity & lesser time required for drying the raw

C. All A., B. and C.

D. High strength & thermal spalling resistance

E. ractories and hence increased rate of production

129. Which of the following does not occur during firing/burning of refractories ?
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A. Removal of water of hydration

B. Vitrification

C. Development of stable mineral form

D. Decrease in crushing strength
130. Zircon refractories have__________________?
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A. High spalling resistance

B. Low co-efficient of expansion

C. High RUL (1600C) and refractoriness (> 2000C)

D. All A., B. and C.
131. Silica bricks are attacked by basic slags at high temperature. Which of the following is not used solely as a binding material ?
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A. Aluminium phosphate

B. Plaster of Paris

C. Water

D. Lime

132. Chrome magnesite brick is not used for lining the___________________?
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A. Bottom hearth of reheating furnace

B. Coke oven regenerator

C. Hearth of soaking pits

D. Burning zone of limestone rotary kilns

133. 10 to 30% magnesite is added to Chromite to produce chrome-magnesite refractories. Magnesite addition is mainly done to improve the _____________ of Chromite?
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A. Crushing strength

B. Resistance to slag

C. Refractoriness

D. Spalling resistance
134. Faster rate of drying of moulded refractories results in high _____________ of refractories?
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A. Green strength

B. Voids

C. Shrinkage

D. Both B. and C.
135. Upper portion of hot metal mixer are lined with mullite bricks, which helps in resisting the_________________?
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A. Washing action of metal

B. Corrosion by layer of slag

C. Both A. & B.

D. Neither A. nor B.

136. Lessing ring is formed by the addition of a partition across the centre of a raschig ring, which results in an area increase of about ______________ percent?
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A. 35

B. 55

C. 5

D. 20
137. Which property is important for bricks used in the combustion chamber & dome of blast furnace stoves ?
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A. All A., B. and C.

B. High resistance to spalling

C. High strength and density

D. High refractoriness
138. Zirconia refractories are not used in_____________________?
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A. Lining high temperature ceramic kilns

B. High frequency induction furnaces in the form of inductors

C. Making sheaths for thermocouple

D. Furnaces subjected to fluctuating temperature
139. To resist spalling tendency, a refractory should have________________?
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A. Low specific heat

B. Greater diffusivity

C. Low thermal co-efficient of expansion

D. All A., B. and C.
140. Thermal diffusivity of a refractory brick is high, when its ____________ is high?
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A. Density

B. Thermal conductivity

C. Specific heat

D. None of these