chemical engineering refractory technology Mcqs
201. Which form of silica has the highest specific gravity ?
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A. Tridymite

B. Quartz

C. All have the same specific gravity

D. Cristobalite

202. Silica bricks are never used for lining the____________________?
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A. Roof of open hearth furnace

B. Dome of blast furnace stoves

C. By-product coke ovens

D. Beehive coke ovens
203. Fireclay refractories____________________?
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A. ible aluminates silicates etc

B. Are not resistant to the action of basic slags

C. All A., B. and C.

D. Combine with salts (e.g. chlorides sulphates etc.) & bases (e.g. lime, magnesia etc.) forming

E. Shrink during firing

204. Which is not an acidic refractory ?
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A. Carbon black

B. Silica

C. Fireclay

D. High alumina refractory

205. Refractories subjected to alternate cycles of heating & cooling are liable to loose their resistance to__________________?
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A. Fusion under load

B. CO attack

C. Thermal spalling

D. Slag attack

206. Which is an acidic refractory ?
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A. Magnesite

B. Dolomite

C. Fireclay

D. Chrome magnesite

207. Fireclay bricks are used in the__________________?
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A. Outer lining of L.D. converter

B. Coke oven walls

C. Hearth bottom of blast furnace

D. Coke ovens regenerator

208. Mullite is chemically represented by_________________?
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A. 2Al2O3. 3SiO2

B. Al2O3. SiO2

C. Al2O3. 2SiO2

D. 3Al2O3. 2SiO2
209. Fusion temperature of pure silica (SiO2) is _______________ C?
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A. 1715

B. 2800

C. 2570

D. 1350

210. Which one contains minimum percentage of SiO2 ?
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A. Sillimanite

B. Firebrick

C. Semi-silica

D. Aluminous firebrick

211. Refractoriness under loads (RUL) is quite close to the fusion temperature (PCE) for _____________ bricks?
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A. Dolomite

B. Silica

C. Very low alumina

D. Fireclay

212. ___________________ is the measure of the strength of refractory under the combined effect of temperature & load ?
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A. Specific gravity

B. Porosity

C. RUL

D. Thermal conductivity

213. Dilatometer is used for the determination of ______________ of refractories?
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A. Resistance to CO attack

B. Permanent linear change

C. RUL

D. Modulus of rupture

214. Pure oxide refractories are generally monocrystalline in nature and are self bonded _______________ bricks are generally used as moderator in nuclear reactors?
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A. Corundum

B. Carborundum

C. Beryllia

D. Thoria

215. Pick out the wrong statement?
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A. Calcined magnesite is also called dead burnt magnesite

B. Graphite refractories are also called plumbago refractories

C. Superduty fireclay bricks correspond to a pyrometric cone equivalent of 26-28

D. Insulating refractories used in place of regular refractory bricks are usually called light weight

E. ractories, and they have similar composition as heavy bricks

216. Porosity of fireclay refractories is _______________ percent?
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A. 25-35

B. 10-May

C. 35-50

D. 10-25
217. With decrease in porosity, the ______________ of the refractories decreases?
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A. None of these

B. Thermal conductivity

C. Strength

D. Spalling resistance
218. Magnesite bricks have poor resistance to attack by _____________ slag?
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A. None of these

B. Acid

C. Lime

D. Basic