Practice Test: Question Set - 14
1. Fireclay bricks are not used in the
- (A) Blast
furnace
- (B) Hot
blast stove
- (C) Cupola
- (D) Wall of coke oven
2. An insulating refractory brick should have high porosity and low thermal conductivity. Which of the following is not used for inducing porosity in the insulating refractory bricks during its manufacture?
- (A) Cork
- (B) Saw dust
- (C) Sand
- (D) Chemically
prepared foam
3. Permeability of bricks is a measure of the
- (A) Refractoriness
- (B) Melting point
- (C) Rate
at which a fluid will pass through the pores
- (D) Expansion during
heating
4. Magnesite refractories are used for the construction of those furnaces, which are
- (A) Not required to
resist the corrosive action of basic slag
- (B) Not subjected to
fluctuation in temperature
- (C) Used for raising
& maintaining high temperature
- (D) Both (b) and (c)
5. Pick out the wrong statement.
- (A) Insulating
refractories used in place of regular refractory bricks are usually called
light weight refractories, and they have similar composition as heavy bricks
- (B) Graphite refractories
are also called plumbago refractories
- (C) Superduty fireclay
bricks correspond to a pyrometric cone equivalent of 26-28
- (D) Calcined magnesite is
also called dead burnt magnesite
6. Outer combustion chamber of blast furnace stove is lined with __________ bricks.
- (A) Fireclay
- (B) Silica
- (C) Chrome
magnesite
- (D) Zirconia
7. Carborundum used for making crucibles for melting non-ferrous metals is chemically
- (A) Silicon
carbide
- (B) Silicon
nitride
- (C) Crystalline
magnesia
- (D) Zirconium
sulphate
8. Roof of a basic electric furnace is made of __________ bricks.
- (A) Superduty
fireclay
- (B) Silica
- (C) Chromite
- (D) None of these
9. Faster rate of drying of moulded refractories results in high __________ of refractories.
- (A) Green strength
- (B) Voids
- (C) Shrinkage
- (D) Both (b) and (c)
10. Which property of refractories is the most important for top section of the blast furnace?
- (A) Resistance to
abrasion
- (B) Resistance to slag
penetration
- (C) Stability
of volume at high temperature
- (D) Resistance to
corrosion by slag
11. Refractories used in/for _________ should have low thermal conductivity.
- (A) Coke ovens
- (B) Insulation
- (C) Regenerators
- (D) Muffle
furnaces
12. Spalling of silica bricks occurs due to abrupt volume changes, when it is cooled below a temperature of _________ °C.
- (A) 770
- (B) 570
- (C) 270
- (D) 70
13. Lower wall courses of soaking pits are made of __________ bricks to avoid the action of molten slag & scale.
- (A) Chrome or magnesite
- (B) Silicon carbide
- (C) Silica
- (D) Low
duty fireclay
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