chemical engineering refractory technology MCQs – Page 8

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 Review each marked answer and report any item that may be outdated or unclear.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
141. Beryllia (which is used in making crucibles for melting uranium & thorium) is superior to alumina in all respects for high temperature (> 1900C ) use, except ?
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A. Cost

B. Electrical conductivity

C. Thermal conductivity

D. Fusion point

142. A steel member used in the furnace construction to take the thrust of the brickwork is called___________________?
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A. Buckstay

B. Baffle

C. Armouring

D. Breast wall

143. Zirconia refractory_________________?
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A. Does not react with basic slags

B. Is produced from baddeleyite

C. Cannot be used as an insulator

D. Has poor electrical conductivity at high temperature

144. Which is not a high alumina refractory ?
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A. Dolomite

B. Corundum

C. Bauxite

D. Mullite

145. Fireclay bricks are not used in the _________________?
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A. Beehive coke oven

B. Combustion chamber of B.F. stoves

C. By-product coke oven walls

D. Coke oven regenerators

146. Firing temperature of magnesite bricks is about _____________ C?
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A. 800-1000

B. 1600-1800

C. 2400-2600

D. 1000-1200

147. Cold crushing strength of fireclay bricks is about ______________ kgf/cm2?
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A. 500-1000

B. 100-150

C. 50-100

D. 200-400
148. Graphite or carbon refractories______________________?
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A. Are not resistant to corrosion by slag

B. Should be used in neutral or reducing atmosphere

C. Exhibit wetting characteristics

D. Exhibit high shrinkage on thermal treatment

149. Carbon refractory blocks ___________________?
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A. Are wetted by molten iron

B. All A., B. and C.

C. Are used in the hearth of blast furnace

D. Are acidic in nature

150. Periclase refractory contains mainly________________?
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A. CaO

B. MgO

C. SiO2

D. Al2O3

151. Chemically, mullite refractories is____________________?
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A. ZrSO4

B. Al2O3

C. ThO2

D. 3Al2O3.2SiO2
152. Insulating refractories should have_______________?
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A. High porosity

B. Low thermal conductivity

C. Both A. and B.

D. Neither A. not B.

153. Use of higher percentage of lime for bonding silica bricks, reduces their__________________?
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A. Strength

B. Abrasion resistance

C. Both A. & B.

D. Neither A. nor B.

154. Si percentage in silica refractories used in the walls of coke oven is about______________________?
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A. 95

B. 45

C. 80

D. 60

155. Porosity is induced in insulating refractories by adding________________?
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A. Ammonium chloride/sulphate

B. Powdered naphthalene

C. Calcium phosphate

D. All A., B. and C.
156. Which of the following is not an acidic refractory?
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A. Magnesia bricks

B. Silica bricks

C. Fireclay bricks

D. Bauxite bricks

157. Rotary kilns meant for calcination of limestone are lined with chrome magnesite in ______________ zone?
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A. Burning

B. All the above

C. Cooling

D. Preheating

158. Rate of slag attack on refractories increases with rise in temperature due to the___________________?
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A. Decreased viscosity of slag

B. Oxidising condition in the furnace

C. Increased thermal conductivity of brick

D. None of these

159. Silicon carbide refractories are used in the _____________?
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A. All A., B. and C.

B. Ceramic recuperators

C. Muffle furnace

D. Zinc smelting furnace

160. Grog__________________?
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A. Contains both alumina and silica

B. Is crushed firebrick

C. Is a non-plastic material

D. All A., B. and C.