Refractory Technology problems
- 1. Refractoriness under loads (RUL) is quite close to the fusion temperature (PCE) for __________ bricks.
Options- A. fireclay
- B. silica
- C. dolomite
- D. very low alumina Discuss
Correct Answer: silica
- 2. Fireclay refractories
Options- A. are not resistant to the action of basic slags.
- B. combine with salts (e.g. chlorides sulphates etc.) & bases (e.g. lime, magnesia etc.) forming fusible aluminates silicates etc.
- C. shrink during firing
- D. all (a), (b) and (c) Discuss
Correct Answer: all (a), (b) and (c)
- 3. Rotary kilns meant for calcination of limestone are lined with chrome magnesite in __________ zone.
Options- A. preheating
- B. cooling
- C. burning
- D. all Discuss
Correct Answer: burning
- 4. In panel test for spalling resistance, the average face temperature of panel assembly is maintained at __________ °C for 24 hours.
Options- A. 700
- B. 1000
- C. 1600
- D. 2000 Discuss
Correct Answer: 1600
- 5. Hot blast main (carrying air at 1000°C) in blast furnace are lined with __________ bricks.
Options- A. silica
- B. fireclay
- C. magnesite
- D. zirconia Discuss
Correct Answer: fireclay
- 6. Ceramic recuperators used for waste heat recovery from high temperature flue gas going out of the furnace is made of
Options- A. fireclay
- B. silicon carbide
- C. corrundum
- D. siliceous fireclay Discuss
Correct Answer: silicon carbide
- 7. Pick out the wrong statement.
Options- 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. Discuss
Correct Answer: Superduty fireclay bricks correspond to a pyrometric cone equivalent of 26-28.
- 8. Dolomite bricks have good resistance to attack by
Options- A. molten steel
- B. iron oxide
- C. lime slag
- D. none of these Discuss
Correct Answer: molten steel
- 9. Magnesite chrome refractories
Options- A. have better spalling resistance than chrome magnesite refractories.
- B. have very low thermal co-efficient of expansion.
- C. are not at all resistant to the corrosive action of iron oxide.
- D. have very low (50 kg/cm2 ) cold crushing strength (C.C.S.), and can not be used in metalcase form. Discuss
Correct Answer: have better spalling resistance than chrome magnesite refractories.
- 10. Silica bricks are never used for lining the
Options- A. beehive coke ovens.
- B. by-product coke ovens.
- C. dome of blast furnace stoves.
- D. roof of open hearth furnace. Discuss
Correct Answer: beehive coke ovens.
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