81. Rotary kilns meant for calcination of limestone are lined with chrome magnesite in __________ zone.
preheating
cooling
burning
all
✅ The correct answer is option C.
Refractory Technology MCQs
82. Which is the most stable crystalline form of silica at room temperature ?
Quartz
Cristobalite
Tridymite
None of these
✅ The correct answer is option A.
83. ‘Spinel’, a refractory mineral is chemically represented as
MgAl2O4
MgAl2O3
MgSO4
MgAl2O3.2H2O
✅ The correct answer is option A.
84. The largest consumer of refractories is the __________ industry.
cement
metallurgical
fertiliser
power
✅ The correct answer is option B.
85. Silica bricks have low spalling resistance below 600°C, due to its
very high thermal conductivity.
high co-efficient of expansion upto this temperature.
high thermal diffusivity.
low refractoriness.
✅ The correct answer is option B.
86. The maximum linear expansion of silica bricks during firing is about __________ percent.
0.5
1
2
3.5
✅ The correct answer is option D.
87. Most Cermets, which normally have high thermal conductivity and high thermal shock resistance, comprises of ceramic & metallic components of __________ percent respectively.
80 and 20
20 and 80
50 and 50
60 and 40
✅ The correct answer is option A.
89. Which property is important for bricks used in the combustion chamber & dome of blast furnace stoves ?
High refractoriness.
High resistance to spalling.
High strength and density.
All (a), (b) and (c).
✅ The correct answer is option A.
90. Rate of slag attack on refractories increases with rise in temperature due to the
decreased viscosity of slag.
increased thermal conductivity of brick.
oxidising condition in the furnace.
none of these.
✅ The correct answer is option A.