Q.1
SiO₂ percentage in firebrick is about
Q.2
High porosity refractory bricks have
Q.3
Which is not a high alumina refractory?
Q.4
Carbon refractories have very high
Q.5
Pick out the wrong statement.
Q.6
RUL of refractories depends on the
Q.7
Firing of refractory brick is done to
Q.8
The linear thermal expansion of __________ bricks upto 1000 °C is very low of the order of ≤ 0.5 percent.
Q.9
__________ of carbon blocks in the hearth of blast furnace helps in avoiding skull formation, when it becomes cold.
Q.10
Bottom of basic open hearth furnace are constructed of
Q.11
Magnesite refractories are used for the construction of those furnaces, which are
Q.12
Natural silica
Q.13
Pick out the wrong statement.
Q.14
Fireclay bricks are not used in the
Q.15
Ramming masses are used for
Q.16
Graphite or carbon refractories
Q.17
Refractories are dried in the
Q.18
Refractoriness/fusion points of 'superduty' refractories is __________ °C.
Q.19
Which of the following has the lowest electrical resistivity?
Q.20
Periclase is
Q.21
Pick out the wrong statement.
Q.22
Fireclay bricks are not used in the
Q.23
With decrease in porosity, the __________ of the refractories decreases.
Q.24
Which refractory must have controlled atmosphere (temperature and humidity) for its safe storage?
Q.25
Pure oxide refractories are generally monocrystaliine in nature and are self bonded __________ bricks are generally used as moderator in nuclear reactors.
Q.26
Which furnace consumes maximum refractory annually in an integrated steel plant?
Q.27
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.
Q.28
Carborundum used for making crucibles for melting non-ferrous metals is chemically
Q.29
Which one contains minimum percentage of SiO₂?
Q.30
Spalling of a refractory means its
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