Refractory Technology pdf Test Paper - Set 11 - ObjectiveBooks

Refractory Technology pdf Test Paper - Set 11

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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