Refractory Technology problems
- 1. Which of the following is not an acidic refractory?
Options- A. Silica bricks
- B. Fireclay bricks
- C. Bauxite bricks
- D. Magnesia bricks Discuss
Correct Answer: Magnesia bricks
- 2. Fireclay refractories have
Options- A. low co-efficient of thermal expansion.
- B. poor thermal spalling resistance.
- C. tendency to expand unduly high during firing.
- D. very high cost. Discuss
Correct Answer: low co-efficient of thermal expansion.
- 3. 'Super refractories' are made from pure
Options- A. carbides
- B. oxides
- C. borides
- D. nitrides Discuss
Correct Answer: oxides
- 4. Chromite refractories are
Options- A. acidic refractory.
- B. neutral refractory.
- C. basic refractory.
- D. fired at a temperature of 600°C only. Discuss
Correct Answer: neutral refractory.
- 5. Spalling resistance of a refractory can not be increased by
Options- A. increasing its porosity.
- B. using a coarser grog during its manufacture.
- C. decreasing its thermal co-efficient of expansion.
- D. making it denser. Discuss
Correct Answer: making it denser.
- 6. Alumina-graphite bricks are used for lining the
Options- A. slide gate in teeming laddies.
- B. continuous casting systems.
- C. both (a) and (b).
- D. neither (a) nor (b). Discuss
Correct Answer: both (a) and (b).
- 7. Zirconia refractory
Options- A. does not react with basic slags.
- B. is produced from baddeleyite.
- C. can not be used as an insulator.
- D. has poor electrical conductivity at high temperature. Discuss
Correct Answer: is produced from baddeleyite.
- 8. With increasing alumina content, the fusion point of high alumina refractories
Options- A. increases.
- B. decreases.
- C. remains constant.
- D. may increase or decrease ; depends on its alumina content. Discuss
Correct Answer: increases.
- 9. Which of the following does not occur during firing/burning of refractories?
Options- A. Removal of water of hydration.
- B. Vitrification.
- C. Decrease in crushing strength.
- D. Development of stable mineral form. Discuss
Correct Answer: Decrease in crushing strength.
- 10. Cermets are
Options- A. composite material containing both ceramic & metallic constituents.
- B. having high strength & resistance to high temperature.
- C. used in space vehicles, missiles & nuclear energy plants.
- D. all (a), (b) and (c). Discuss
Correct Answer: all (a), (b) and (c).
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