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- Question
Pebble mills are tumbling mills widely used for grinding in the manufacture of paints & pigments and cosmetic industries, where iron contamination in the product is highly objectionable. Pebbles used in pebble mill are made of
Options- A. bronze
- B. stainless steel
- C. flint or porcelain
- D. concrete
- Correct Answer
- flint or porcelain
- 1. For a non-spherical particle, the sphericity
Options- A. is defined as the ratio of surface area of a sphere having the same volume as the particle to the actual surface area of the particle.
- B. has the dimension of length.
- C. is always less than 1.
- D. is the ratio of volume of a sphere having the same surface area as the particle to the actual volume of the particle. Discuss
- 2. Size reduction of __________ is accomplished in steam heated rollers and roll crushers.
Options- A. resins
- B. gums
- C. hard rubber
- D. waxes Discuss
- 3. Which of the following is not an ultrafine grinder (colloid mill)?
Options- A. Micronizers
- B. Agitated mills and fluid energy mills
- C. Toothed roll crusher
- D. Hammer mills with internal classification Discuss
- 4. __________ centrifuge is normally used in sugar mills.
Options- A. Tubular bowl
- B. Disc-bowl
- C. Suspended batch basket
- D. Perforated horizontal basket continuous Discuss
- 5. Filter aid is used to
Options- A. increase the rate of filtration.
- B. decrease the pressure drop.
- C. increase the porosity of the cake.
- D. act as a support base for the septum. Discuss
- 6. In continuous filtration (at a constant pressure drop), filtrate flow rate varies inversely as the
Options- A. square root of the velocity.
- B. square of the viscosity.
- C. filtration time only.
- D. washing time only. Discuss
- 7. Pick out the correct statement:
Options- A. Removal of iron from ceramic material is necessitated (by magnetic separation method) so as to avoid discolouration of ceramic products.
- B. The operating cost of shaking screen is more than that of a vibrating screen.
- C. Screen capacity does not depend upon the specific gravity of the minerals.
- D. Asphalt is best crushed using toothed roll crusher. Discuss
- 8. Froth floatation is the most suitable for treating
Options- A. iron ores
- B. sulphide ores
- C. quartzite
- D. none of these Discuss
- 9. Balls for ball mills are never made of
Options- A. forged/cast steel
- B. lead
- C. cast iron
- D. alloy steel Discuss
- 10. Which of the following is not categorised as a "mechanical operation"?
Options- A. Agitation
- B. Filtration
- C. Size enlargement
- D. Humidification Discuss
Mechanical Operations problems
Search Results
Correct Answer: is defined as the ratio of surface area of a sphere having the same volume as the particle to the actual surface area of the particle.
Correct Answer: hard rubber
Correct Answer: Toothed roll crusher
Correct Answer: Suspended batch basket
Correct Answer: increase the porosity of the cake.
Correct Answer: square root of the velocity.
Correct Answer: Removal of iron from ceramic material is necessitated (by magnetic separation method) so as to avoid discolouration of ceramic products.
Correct Answer: sulphide ores
Correct Answer: lead
Correct Answer: Humidification
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