8247 + Mcqs in Chemical Engineering Page 6 McqOptions

251.	The largest consumer of refractories is the __________ industry.
A.	cement
B.	metallurgical
C.	fertiliser
D.	power
Answer» C. fertiliser

Discussion

252.	Use of higher percentage of lime for bonding silica bricks, reduces their
A.	strength
B.	abrasion resistance
C.	both (a) & (b)
D.	neither (a) nor (b)
Answer» D. neither (a) nor (b)

Discussion

253.	Graphite or carbon refractories
A.	exihibit wetting characteristics.
B.	should be used in neutral or reducing atmosphere.
C.	exhibit high shrinkage on thermal treatment.
D.	are not resistant to corrosion by slag.
Answer» C. exhibit high shrinkage on thermal treatment.

Discussion

254.	__________ bricks are used in the burning zone of a cement rotary kiln.
A.	High alumina
B.	Fireclay
C.	Thoria
D.	Silicon carbide
Answer» B. Fireclay

Discussion

255.	Furnace atmosphere for softening temperature determination of refractories (in which segar cones are placed) should be
A.	oxidising
B.	neutral
C.	either (a) or (b)
D.	neither (a) nor (b)
Answer» D. neither (a) nor (b)

Discussion

256.	Chrome magnesite brick is not used for lining the
A.	hearth of soaking pits.
B.	bottom hearth of reheating furnace.
C.	coke oven regenerator.
D.	burning zone of limestone rotary kilns.
Answer» D. burning zone of limestone rotary kilns.

Discussion

257.	Roof of a basic open hearth furnace is lined with __________ bricks.
A.	silica
B.	fireclay
C.	dolomite
D.	magnesite
Answer» B. fireclay

Discussion

258.	High alumina refractories are used in the
A.	dome of blast furnace stoves.
B.	electric arc furnace roof.
C.	glass melting furnaces.
D.	all (a), (b) and (c).
Answer» E.

Discussion

259.	Highest melting (m.p = 3070 C) oxide refractory is
A.	alumina
B.	thoria
C.	zirconia
D.	magnesia
Answer» C. zirconia

Discussion

260.	Which one contains minimum percentage of SiO2?
A.	Firebrick
B.	Sillimanite
C.	Semi-silica
D.	Aluminous firebrick
Answer» C. Semi-silica

Discussion

261.	Porosity of silica bricks varies from __________ percent.
A.	5 to 10
B.	20 to 30
C.	45 to 60
D.	60 to 75
Answer» C. 45 to 60

Discussion

262.	Rate of slag attack on refractories increases with rise in temperature due to the
A.	decreased viscosity of slag.
B.	increased thermal conductivity of brick.
C.	oxidising condition in the furnace.
D.	none of these.
Answer» B. increased thermal conductivity of brick.

Discussion

263.	Semi-silica bricks compared to silica bricks have
A.	less fusion point.
B.	better spalling resistance.
C.	both (a) and (b).
D.	neither (a) not (b).
Answer» D. neither (a) not (b).

Discussion

264.	Magnesite refractories have low resistance to
A.	attack by basic slag.
B.	abrasion.
C.	disintegration on sudden change of temperature.
D.	both (b) and (c).
Answer» E.

Discussion

265.	Which of the following is not a high alumina refractory material ?
A.	Kyanite
B.	Sillimanite
C.	Diaspore
D.	Periclase
Answer» E.

Discussion

266.	Magnesite chrome bricks are used in the
A.	roof lining of basic open hearth & other basic furnaces.
B.	reheating furnaces.
C.	soaking pits.
D.	all (a), (b) and (c).
Answer» E.

Discussion

267.	Carbon bricks are not used in the lining of the
A.	combustion chamber of blast furnace stoves.
B.	electric furnaces.
C.	highly chemical resistant equipments.
D.	blast furnace hearth.
Answer» B. electric furnaces.

Discussion

268.	Maximum apparent porosity of magnesite bricks is about __________ percent.
A.	8
B.	24
C.	44
D.	58
Answer» C. 44

Discussion

269.	Dilatometer is used for the determination of __________ of refractories.
A.	modulus of rupture
B.	permanent linear change
C.	resistance to CO attack
D.	RUL
Answer» C. resistance to CO attack

Discussion

270.	With decrease in porosity, the __________ of the refractories decreases.
A.	strength
B.	thermal conductivity
C.	spalling resistance
D.	none of these
Answer» D. none of these

Discussion

271.	Which property is important for bricks used in the combustion chamber & dome of blast furnace stoves ?
A.	High refractoriness.
B.	High resistance to spalling.
C.	High strength and density.
D.	All (a), (b) and (c).
Answer» B. High resistance to spalling.

Discussion

272.	The maximum linear expansion of silica bricks during firing is about __________ percent.
A.	0.5
B.	1
C.	2
D.	3.5
Answer» E.

Discussion

273.	SiO2 percentage in firebrick is about
A.	35-40
B.	55-60
C.	80-85
D.	>94
Answer» C. 80-85

Discussion

274.	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» E.

Discussion

275.	Magnesite bricks have poor resistance to attack by __________ slag.
A.	lime
B.	basic
C.	acid
D.	none of these
Answer» D. none of these

Discussion

276.	Carbon refractories
A.	do not burn/oxidise, when exposed to air on heating.
B.	are not attacked by slags, as they are not wetted by melts.
C.	do not resist temperature fluctuations.
D.	have extremely low thermal & electrical conductivities.
Answer» C. do not resist temperature fluctuations.

Discussion

277.	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» E.

Discussion

278.	Porosity of fireclay refractories is __________ percent.
A.	5-10
B.	10-25
C.	25-35
D.	35-50
Answer» C. 25-35

Discussion

279.	To resist spalling tendency, a refractory should have
A.	greater diffusivity.
B.	low specific heat.
C.	low thermal co-efficient of expansion.
D.	all (a), (b) and (c).
Answer» E.

Discussion

280.	Cold crushing strength of fireclay bricks is about __________ kgf/cm2.
A.	50-100
B.	100-150
C.	200-400
D.	500-1000
Answer» D. 500-1000

Discussion

281.	Refractoriness under load (RUL) of fireclay bricks (under a load of 2 kg/cm2 ) is __________ C.
A.	500
B.	1000
C.	>1350
D.	>2000
Answer» D. >2000

Discussion

282.	Dolomite bricks have good resistance to attack by
A.	molten steel
B.	iron oxide
C.	lime slag
D.	none of these
Answer» B. iron oxide

Discussion

283.	__________ of carbon blocks in the hearth of blast furnace helps in avoiding skull formation, when it becomes cold.
A.	High thermal conductivity
B.	Low porosity
C.	Non-wetting characteristics
D.	High density
Answer» D. High density

Discussion

284.	The highest melting pure oxide (m.p. > 3000 C)is
A.	thoria
B.	alumina
C.	beryllia
D.	zirconia
Answer» B. alumina

Discussion

285.	__________ bricks should not be used in oxidising atmosphere.
A.	Tar dolomite
B.	Carbon
C.	Silica
D.	Fireclay
Answer» C. Silica

Discussion

286.	Most Cermets, which normally have high thermal conductivity and high thermal shock resistance, comprises of ceramic & metallic components of __________ percent respectively.
A.	80 and 20
B.	20 and 80
C.	50 and 50
D.	60 and 40
Answer» B. 20 and 80

Discussion

287.	Which is not a high alumina refractory ?
A.	Mullite
B.	Corrundum
C.	Bauxite
D.	Dolomite
Answer» E.

Discussion

288.	Pure oxide refractories are generally monocrystaliine in nature and are self bonded __________ bricks are generally used as moderator in nuclear reactors.
A.	Beryllia
B.	Carborundum
C.	Corundum
D.	Thoria
Answer» B. Carborundum

Discussion

289.	Faster rate of drying of moulded refractories results in high __________ of refractories.
A.	green strength
B.	voids
C.	shrinkage
D.	both (b) and (c)
Answer» E.

Discussion

290.	Which is an acidic refractory ?
A.	Magnesite
B.	Dolomite
C.	Fireclay
D.	Chrome magnesite
Answer» D. Chrome magnesite

Discussion

291.	Carborundum used for making crucibles for melting non-ferrous metals is chemically
A.	silicon carbide
B.	silicon nitride
C.	crystalline magnesia
D.	zirconium sulphate
Answer» B. silicon nitride

Discussion

292.	An ideal refractory should have high
A.	spalling rate
B.	fusion point
C.	shrinkage ability
D.	none of these
Answer» C. shrinkage ability

Discussion

293.	Ganister is a source of the
A.	silica
B.	periclase
C.	lime
D.	none of these
Answer» B. periclase

Discussion

294.	Which brick undergoes maximum shrinkage on drying ?
A.	Tar bonded dolomite bricks
B.	Fireclay bricks
C.	Magnesite bricks
D.	Chromite bricks
Answer» C. Magnesite bricks

Discussion

295.	Which is the stable form of silica upto 1470 C ?
A.	Quartz
B.	Cristobalite
C.	Tridymite
D.	None of these
Answer» D. None of these

Discussion

296.	Hot face insulating linings of high purity alumina fused mullite are used, where
A.	very high temperatures are involved.
B.	highly reducing conditions are involved.
C.	presence of iron or silica is harmful.
D.	all (a), (b) and (c).
Answer» E.

Discussion

297.	__________ is not a single oxiderefractory.
A.	Zirconia
B.	Silicon carbide
C.	Magnesia
D.	None of these
Answer» C. Magnesia

Discussion

298.	Refractory bricks having lower porosity have
A.	high insulating properties
B.	low heat capacity
C.	low thermal conductivity
D.	greater strength
Answer» E.

Discussion

299.	Hot blast main (carrying air at 1000 C) in blast furnace are lined with __________ bricks.
A.	silica
B.	fireclay
C.	magnesite
D.	zirconia
Answer» C. magnesite

Discussion

300.	High alumina refractory compared to fireclay bricks have
A.	less load bearing capacity.
B.	less resistance to slag attack.
C.	low refractoriness.
D.	high resistance to thermal shock and creep.
Answer» E.

Discussion

Explore topic-wise MCQs in Engineering.

The largest consumer of refractories is the __________ industry.

Use of higher percentage of lime for bonding silica bricks, reduces their

Graphite or carbon refractories

__________ bricks are used in the burning zone of a cement rotary kiln.

Furnace atmosphere for softening temperature determination of refractories (in which segar cones are placed) should be

Chrome magnesite brick is not used for lining the

Roof of a basic open hearth furnace is lined with __________ bricks.

High alumina refractories are used in the

Highest melting (m.p = 3070 C) oxide refractory is

Which one contains minimum percentage of SiO2?

Porosity of silica bricks varies from __________ percent.

Rate of slag attack on refractories increases with rise in temperature due to the

Semi-silica bricks compared to silica bricks have

Magnesite refractories have low resistance to

Which of the following is not a high alumina refractory material ?

Magnesite chrome bricks are used in the

Carbon bricks are not used in the lining of the

Maximum apparent porosity of magnesite bricks is about __________ percent.

Dilatometer is used for the determination of __________ of refractories.

With decrease in porosity, the __________ of the refractories decreases.

Which property is important for bricks used in the combustion chamber &amp; dome of blast furnace stoves ?

The maximum linear expansion of silica bricks during firing is about __________ percent.

SiO2 percentage in firebrick is about

Porosity is induced in insulating refractories by adding

Magnesite bricks have poor resistance to attack by __________ slag.

Carbon refractories

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

Porosity of fireclay refractories is __________ percent.

To resist spalling tendency, a refractory should have

Cold crushing strength of fireclay bricks is about __________ kgf/cm2.

Refractoriness under load (RUL) of fireclay bricks (under a load of 2 kg/cm2 ) is __________ C.

Dolomite bricks have good resistance to attack by

__________ of carbon blocks in the hearth of blast furnace helps in avoiding skull formation, when it becomes cold.

The highest melting pure oxide (m.p. &gt; 3000 C)is

__________ bricks should not be used in oxidising atmosphere.

Most Cermets, which normally have high thermal conductivity and high thermal shock resistance, comprises of ceramic &amp; metallic components of __________ percent respectively.

Which is not a high alumina refractory ?

Pure oxide refractories are generally monocrystaliine in nature and are self bonded __________ bricks are generally used as moderator in nuclear reactors.

Faster rate of drying of moulded refractories results in high __________ of refractories.

Which is an acidic refractory ?

Carborundum used for making crucibles for melting non-ferrous metals is chemically

An ideal refractory should have high

Ganister is a source of the

Which brick undergoes maximum shrinkage on drying ?

Which is the stable form of silica upto 1470 C ?

Hot face insulating linings of high purity alumina fused mullite are used, where

__________ is not a single oxiderefractory.

Refractory bricks having lower porosity have

Hot blast main (carrying air at 1000 C) in blast furnace are lined with __________ bricks.

High alumina refractory compared to fireclay bricks have

Which property is important for bricks used in the combustion chamber & dome of blast furnace stoves ?

The highest melting pure oxide (m.p. > 3000 C)is

Most Cermets, which normally have high thermal conductivity and high thermal shock resistance, comprises of ceramic & metallic components of __________ percent respectively.