Refractory Technology MCQs – Competitive Latest Chemical Engineering MCQs
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Latest Chemical Engineering MCQs
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Latest Refractory Technology Mcqs
The most occurred mcqs of Refractory Technology in past papers. Past papers of Refractory Technology Mcqs. Past papers of Refractory Technology Mcqs . Mcqs are the necessary part of any competitive / job related exams. The Mcqs having specific numbers in any written test. It is therefore everyone have to learn / remember the related Refractory Technology Mcqs. The Important series of Refractory Technology Mcqs are given below:
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?
A. 35
B. 20
C. 5
D. 55
In chemical process equipments, the conical bottom heads used, usually has an apex angle of____________________?
A. 40°
B. 20°
C. 60°
D. 80°
Si percentage in silica refractories used in the walls of coke oven is about______________________?
A. 60
B. 45
C. 80
D. 95
Chrome magnesite bricks are_________________?
A. Neutral in nature
B. Acidic in nature
C. Having higher RUL than silica bricks
D. Made by mixing 30% Chromite and 70% Periclase
Maximum shrinkage in volume occurring during burning/firing of dried refractories may be as high as ______________ percent?
A. 15
B. 10
C. 20
D. 30
Which of the following consumes the maximum tonnage of refractories annually in an integrated steel plant ?
A. Reheating furnace
B. Soaking pits
C. L.D. converter
D. Rotary lime kiln
Lower part of hot metal mixer are lined with _____________ bricks?
A. High alumina
B. Superduty fireclay
C. Silica
D. Carborundum
Bauxite calcining rotary kilns are lined with ________________ bricks?
A. Carbon
B. Fireclay
C. 85% alumina
D. Corundum
Spalling of a refractory means its____________________?
A. Resistance to compressive loads
B. Fracture due to uneven expansion at high temperature
C. Softening
D. Resistance to chemical action of gases and molten fluxes
The linear thermal expansion of _______________ bricks upto 1000 °C is very low of the order of ≤ 0.5 percent?
A. Fireclay
B. Magnesite
C. Silica
D. Corundum
Chrome magnesite is not used in the ____________________?
A. Aluminium melting furnaces
B. Inner lining of L.D. converter
C. Wear out lining of steel melting furnaces
D. All A., and B. and C.
______________ bricks are used in the burning zone of a cement rotary kiln ?
A. High alumina
B. Thoria
C. Fireclay
D. Silicon carbide
Maximum water percentage in refractory mix meant for hand moulding may be as high as _____________ percent?
A. 5-7
B. 2-3
C. 7-12
D. 14-20
Which of the following has the lowest electrical resistivity ?
A. Graphite
B. Alumina
C. Fireclay
D. Zircon
Refractory castables are used for__________________?
A. Patch work
B. Producing monolithic linings
C. Minimising the number of joints in the structure
D. All A., B. and C.
Thermodynamics Mcqs
Silicon carbide refractories have very low ___________________?
A. Thermal conductivity
B. Refractoriness (< 1700°C)
C. Resistance to thermal shock
D. None of these
Carbon refractories are exclusively used in the_________________?
A. Hearth of blast furnace
B. Regenerators of coke oven
C. Walls of coke oven
D. Side wall of soaking pits
Because of its very high refractoriness of the order of __________ °C, silicon carbide refractories are used in zinc smelting furnace, muffle furnace and for supporting the wares in tunnel kilns ?
A. 2200
B. 1800
C. 2400
D. 2700
Which is the most stable crystalline form of silica at room temperature ?
A. Quartz
B. Tridymite
C. Cristobalite
D. None of these
Which of the following bricks has the most close values of RUL and PCE ?
A. Silica bricks
B. High alumina bricks
C. Fireclay bricks
D. Tar dolomite bricks
Roof of a basic open hearth furnace is lined with ______________ bricks?
A. Silica
B. Dolomite
C. Fireclay
D. Magnesite
Chrome magnesite bricks are used in the_________________?
A. Side walls of soaking pits and arc furnaces
B. Burner block of glass tanks
C. Copper melting furnaces & converters
D. All A., B. and C.
Refractory materials are never used in the construction of _________________?
A. Orton cones
B. Segar cones
C. Pressure vessels
D. Ovens & retorts
Graphite or carbon refractories______________________?
A. Exhibit high shrinkage on thermal treatment
B. Should be used in neutral or reducing atmosphere
C. Exhibit wetting characteristics
D. Are not resistant to corrosion by slag
Zirconia refractory_________________?
A. Cannot be used as an insulator
B. Is produced from baddeleyite
C. Does not react with basic slags
D. Has poor electrical conductivity at high temperature
Carbon refractories have very high __________________?
A. Wetting characteristics
B. Thermal conductivity
C. Refractoriness
D. Both B. and C.
An ideal refractory should have high__________________?
A. Shrinkage ability
B. Fusion point
C. Spalling rate
D. None of these
Fusion point of an acidic refractory material is________________?
A. Not affected by the addition of basic oxides
B. Reduced by the addition of basic oxides
C. Increased by the addition of basic oxides
D. Always more than 2500°C
Segar cones are used for the determination of ____________ of refractories?
A. Softening temperature
B. Electrical conductivity
C. Spalling resistance
D. Resistance to slag attack
Porosity is induced in insulating refractories by adding________________?
A. Ammonium chloride/sulphate
B. Powdered naphthalene
C. Calcium phosphate
D. All A., B. and C.
Machine moulding of dry mixture of refractories requires a pressure of the order of _____________ kg/cm2?
A. 100
B. 10
C. 500
D. 1000
Carbon bricks are not used in the lining of the_________________?
A. Combustion chamber of blast furnace stoves
B. Blast furnace hearth
C. Highly chemical resistant equipments
D. Electric furnaces
Grog addition in fireclay during brick manufacture is done to_________________?
A. Impart greater spalling resistance
B. Reduce its shrinkage on heating
C. Enhance the strength of fired refractories
D. All A., B. and C.
Which of the following does not occur during firing/burning of refractories ?
A. Vitrification
B. Removal of water of hydration
C. Decrease in crushing strength
D. Development of stable mineral form
Conversion of silica mineral to Cristobalite is accompanied by reduction in its ____________________?
A. Volume
B. Specific gravity
C. Both of the above
D. Neither of the above
Magnesite chrome bricks are used in the___________________?
A. Roof lining of basic open hearth & other basic furnaces
B. Soaking pits
C. Reheating furnaces
D. All A., B. and C.
Process Control And Instrumentation Mcqs
Silica bricks are attacked by basic slags at high temperature. Which of the following is not used solely as a binding material ?
A. Lime
B. Water
C. Aluminium phosphate
D. Plaster of Paris
Periclase is___________________?
A. Crystalline form of MgO
B. ZrSO4
C. MgCO3
D. Amorphous magnesite
RUL of refractories depends on the _____________________?
A. Physical structure
B. Chemical composition
C. Presence of impurities like iron & alkali
D. All A., B. and C.
Which one contains maximum percentage of Al2O3 ?
A. Magnesite
B. Sillimanite
C. Firebrick
D. Aluminous firebrick
Which is not a basic refractory ?
A. Magnesite
B. Chrome magnesite
C. Dolomite
D. Silicon carbide
Silica refractories__________________?
A. crack when subjected to sudden change of temperature
B. Have lower thermal conductivity than fireclay bricks
C. Cannot be used in the dome of hot blast stoves
D. All A., B. and C.
Firing of refractory brick is done to __________________?
A. Develop stable mineral forms in them
B. Dehydrate the dried refractory
C. Form ceramic bonds necessary for development of high crushing strength in the finished product
D. All A., B. and C.
Ferromagnetic ceramic material is not used in the__________________?
A. Thermal insulation
B. Magnetic switches
C. Transformers
D. Television sets
Which one expands on heating ?
A. Silica bricks
B. Fireclay bricks
C. Both of the above
D. Neither of the above
_____________ nozzles are used in continuous casting of steel?
A. Zircon
B. Carborundum
C. Thoria
D. Beryllia
Chromite refractories_____________________?
A. Are resistant to basic slag
B. (Free from silica) have better thermal fatigue resistance than silica and magnesite refractories.
C. Are bonded with lime and clay
D. All A., B. and C.
Zircon refractories have__________________?
A. High spalling resistance
B. High RUL (1600°C) and refractoriness (> 2000°C)
C. Low co-efficient of expansion
D. All A., B. and C.
Cermets are combination of ceramic and metallic materials due to which they have high strength & resistance to high temperature. Cermets are used in the_______________?
A. Roof of electric furnaces
B. Nuclear reactors, missiles & space crafts
C. Insulation of high temperature furnaces
D. Hearth of the blast furnace
Which is the stable form of silica upto 1470°C ?
A. Cristobalite
B. Quartz
C. Tridymite
D. None of these
Thermal spalling mainly occurs during _____________ of furnaces?
A. Warming up
B. Cooling down
C. Both A. & B.
D. Neither A. nor B.
High alumina refractories are used in the ___________________?
A. Electric arc furnace roof
B. Dome of blast furnace stoves
C. Glass melting furnaces
D. All A., B. and C.
_____________ is not a single oxide-refractory?
A. Magnesia
B. Silicon carbide
C. Zirconia
D. None of these
Chrome magnesite brick is not used for lining the___________________?
A. Bottom hearth of reheating furnace
B. Hearth of soaking pits
C. Coke oven regenerator
D. Burning zone of limestone rotary kilns
Fluid Mechanics Mcqs
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. 50 and 50
C. 20 and 80
D. 60 and 40
____________ of carbon blocks in the hearth of blast furnace helps in avoiding skull formation, when it becomes cold?
A. Low porosity
B. High thermal conductivity
C. Non-wetting characteristics
D. High density
Rotary kilns meant for calcination of limestone are lined with chrome magnesite in ______________ zone?
A. Cooling
B. Preheating
C. Burning
D. All the above
Semi-silica bricks compared to silica bricks have_______________?
A. Better spalling resistance
B. Less fusion point
C. Both A. and B.
D. Neither A. not B.
Which of the following impurities reduces the refractoriness of magnesite bricks ?
A. CaO
B. Al2O3
C. SiO2
D. All A., B. & C.
SiO2 percentage in firebrick is about____________________?
A. 80-85
B. 55-60
C. 35-40
D. > 94
‘Spinel’, a refractory mineral is chemically represented as____________________?
A. MgAl2O4
B. MgSO4
C. MgAl2O3
D. MgAl2O3.2H2O
With increase in the density of silica refractories, its_______________?
A. Spalling resistance reduces
B. Resistance to slag attack increases
C. Both A. and B.
D. Neither A. nor B.
Mixing of ground refractory material and water is done in a ______________ mill?
A. Pug
B. Tube
C. Ball
D. Rod
Silicon carbide refractories are used in the _____________?
A. Zinc smelting furnace
B. Muffle furnace
C. Ceramic recuperators
D. All A., B. and C.
Firing temperature of magnesite bricks is about _____________ °C?
A. 1000-1200
B. 800-1000
C. 1600-1800
D. 2400-2600
Which of the following is not an acidic refractory?
A. Fireclay bricks
B. Silica bricks
C. Bauxite bricks
D. Magnesia bricks
Grog__________________?
A. Is crushed firebrick
B. Contains both alumina and silica
C. Is a non-plastic material
D. All A., B. and C.
Except _____________, all other refractories are bad conductors of electricity (i.e, have low electrical conductivity)?
A. Carborundum
B. Fireclay
C. Graphite
D. Chromite
Refractoriness of a typical silica brick corresponds to Segar cone number, ’32’, which is equivalent to a temperature of _____________ °C?
A. 1520
B. 1380
C. 1710
D. 1915
With increase in the alumina content in firebricks, its fusion point (refractoriness) ?
A. Remains unchanged
B. Decreases linearly
C. Increases
D. Decreases