Practice Test: Question Set - 11
1. With decrease in porosity, the _________ of the refractories decreases.
- (A) Strength
- (B) Thermal conductivity
- (C) Spalling resistance
- (D) None of these
2. Refractories are dried in the
- (A) Rotary kilns
- (B) Tunnel kilns
- (C) Sun
- (D) None of these
3. ________ bricks should not be used in oxidizing atmosphere.
- (A) Tar dolomite
- (B) Carbon
- (C) Silica
- (D) Fireclay
4. Which refractory must have controlled atmosphere (temperature and humidity) for its safe storage?
- (A) Tar bonded dolomite bricks
- (B) Fireclay bricks
- (C) Mullite bricks
- (D) Magnesite bricks
5. Magnesite bricks have poor resistance to attack by _________ slag.
- (A) Lime
- (B) Basic
- (C) Acid
- (D) None of these
6. An indication of degree of firing in silica brick is its
- (A) Specific gravity
- (B) Fusion point
- (C) RUL
- (D) None of these
7. Which is not a natural insulating material?
- (A) Diatomaceous earth/kieselgur
- (B) Asbestos
- (C) Vermiculite
- (D) None of these
8. Which is not an alumino-silicate refractory?
- (A) Fireclay bricks
- (B) Mullite bricks
- (C) Tar dolomite bricks
- (D) High alumina bricks
9. Which of the following is not a high alumina refractory material?
- (A) Kyanite
- (B) Sillimanite
- (C) Diaspore
- (D) Periclase
10. Resistance to slag attack of a refractory
- (A) Depends on the nature of slag & refractory
- (B) Decreases at higher temperature
- (C) Decreases, if defective joints & cracks
exist in the refractory
- (D) All (a), (b) and (c)
11. ________ is the measure of the strength of refractory under the combined effect of temperature & load.
- (A) Porosity
- (B) RUL
- (C) Specific gravity
- (D) Thermal conductivity
12. Fireclay bricks are never used in the
- (A) Beehive oven
- (B) Coke oven walls
- (C) Zinc roaster
- (D) Lead blast furnace
13. Which one contains minimum percentage of SiO2?
- (A) Firebrick
- (B) Sillimanite
- (C) Semi-silica
- (D) Aluminous firebrick
14. Magnesite bricks are used in those parts of furnaces, which are
- (A) Subjected to temperature fluctuation
- (B) Required to resist corrosive basic slag
- (C) Subjected to high load
- (D) None of these
15. Pure bauxite is the best raw material for the manufacture of high alumina refractories, in which maximum alumina content can be as high as ________ percent.
- (A) 55
- (B) 70
- (C) 80
- (D) 90
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