91. Zirconia refractory
does not react with basic slags.
is produced from baddeleyite.
can not be used as an insulator.
has poor electrical conductivity at high temperature.
✅ The correct answer is option B.
Refractory Technology MCQs
92. Use of higher percentage of lime for bonding silica bricks, reduces their
strength
abrasion resistance
both (a) & (b)
neither (a) nor (b)
✅ The correct answer is option C.
93. Which is a neutral refractory ?
Graphite
Magnesite chrome
Silica
Magnesia
✅ The correct answer is option A.
94. Addition of grog in fireclay brick during its manufacture is advantageous, because it results in
less shrinkage in heating, decreased apparent porosity & increased specific gravity.
high strength & thermal spalling resistance.
less addition of water to get a workable plasticity & lesser time required for drying the raw refractories and hence increased rate of production.
all (a), (b) and (c).
✅ The correct answer is option D.
95. Chromite refractories are used in
bottom of soaking pits.
between acid & basic linings in basic open hearth furnaces to prevent their chemical action with each other.
both (a) & (b)
neither (a) and (b)
✅ The correct answer is option C.
96. Chromite refractories are
acidic refractory.
neutral refractory.
basic refractory.
fired at a temperature of 600°C only.
✅ The correct answer is option B.
97. Porosity of silica bricks varies from __________ percent.
5 to 10
20 to 30
45 to 60
60 to 75
✅ The correct answer is option B.
98. Sillimanite is a __________ refractory.
basic
neutral
high alumina
insulating
✅ The correct answer is option C.
99. Which form of silica has the highest specific gravity ?
Quartz
Cristobalite
Tridymite
All have the same specific gravity
✅ The correct answer is option A.
100. Magnesite refractories have low resistance to
attack by basic slag.
abrasion.
disintegration on sudden change of temperature.
both (b) and (c).
✅ The correct answer is option D.