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- Question
Work index is the gross energy (kWh/tonne of feed) necessary to reduce a very large feed to such a size that 80% of product particles will pass through a 0.1 mm screen. The value of work index determined for wet grinding should be multiplied with __________ to get the same for dry grinding.
Options- A. 1.0
- B. 0.5
- C. 1.34
- D. 4.34
- Correct Answer
- 1.34
- 1. Shell and leaf filter as compared to plate and frame filter
Options- A. entails less labor cost.
- B. facilitates filtration under higher pressure.
- C. provides more effective washing.
- D. all (a), (b) & (c) Discuss
- 2. Angle of nip of the crushing rolls does not depend upon the
Options- A. diameter of the rolls
- B. speed of the rolls
- C. product size
- D. feed size Discuss
- 3. In constant pressure filtration,
Options- A. resistance decreases with time
- B. rate of filtration is constant
- C. rate of filtration increases with time
- D. rate of filtration decreases with time Discuss
- 4. Traces of liquid tar fog present in coke oven gas is separated using
Options- A. electrostatic precipitator
- B. cyclone separator
- C. strainer
- D. none of these Discuss
- 5. Choke crushing (in case of a Jaw crusher) compared to free crushing
Options- A. results in increased capacity.
- B. consumes less power.
- C. consumes more power.
- D. both (a) and (c). Discuss
- 6. __________ are mixed using ribbon blenders.
Options- A. Lumpy solids and low viscosity liquids
- B. Dry powders
- C. High viscosity liquids
- D. Thick pastes Discuss
- 7. The critical speed of a trommel (N) is related to its dia (D) as
Options- A. N ?
- B. N ? D
- C. N ? D
- D. N ?
Discuss
- 8. The process by which fine solids is removed from liquids is termed as
Options- A. decantation
- B. flocculation
- C. sedimentation
- D. classification Discuss
- 9. For crushing of solids, the Rittinger's law states that the work required for crushing is proportional to
Options- A. the new surface created.
- B. the size reduction ratio.
- C. the change in volume due to crushing.
- D. none of these. Discuss
- 10. Activators are those chemicals which help buoying up one mineral in preference to the other in the froth floatation process. Which of the following is an activator?
Options- A. Cresylic acid
- B. Copper sulphate
- C. Calcium carbonate
- D. Sodium carbonate Discuss
Mechanical Operations problems
Search Results
Correct Answer: all (a), (b) & (c)
Correct Answer: speed of the rolls
Correct Answer: rate of filtration decreases with time
Correct Answer: electrostatic precipitator
Correct Answer: consumes more power.
Correct Answer: Dry powders
Correct Answer: N ?
Correct Answer: sedimentation
Correct Answer: the new surface created.
Correct Answer: Copper sulphate
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