22351. Coal is finally pulverised to 200 mesh size for burning in boilers by a
22352. Crushing efficiency is the ratio of the
22353. The resistance offered by the filter used in a bag filter is proportional to (where, c = dust concentration, and s = particle size )
22354. Cement clinker is reduced to fine size by a
22355. The crushed material received for separation is called feed or
22356. For spheres, volume shape factor is given by
22357. Which of the following agitators having a large blade area, rotating at slow speed is used for mixing high viscosity liquids ( > 50000 centipoise) ?
22358. __________ is defined as the geometric mean of the relative rejections and the relative recoveries of two minerals.
22359. The operating speed of a ball mill should be __________ the critical speed.
22360. Use of baffles in agitators help in minimising the __________ tendency.
22361. __________ are used for the separation of coarse particles from a slurry of fine particles.
22362. Fibrous material is broken by a
22363. __________ is the most suitable for compounding rubber and plastic solids.
22364. Out of the following size reduction equipments, the maximum feed size can be accepted by the
22365. Bucket elevators are not suitable for the vertical lifting of __________ materials.
22366. The most common filter aid is
22367. For removal of very small amounts of precipitate from large volume of water, the most suitable filter is the __________ filter.
22368. For separation of sugar solution from settled out mud, we use a __________ filter.
22369. The sphericity of a cylinder of 1 mm diameter and length 3 mm is
22370. Pulverised coal passing through 200 mesh screen has a diameter of 0.074 mm (74 micron). The same passing through 50 mesh screen will have a dia of __________ mm.
22371. What is the selectivity index, if the grade of tailings & concentrate is the same ?
22372. The most suitable equipment used to devulcanise rubber scrap and to make water dispersion & rubber solution is a
22373. Traces of solids are removed from, liquid in a
22374. __________ balls capable of grinding the feed in a ball mill gives the maximum efficiency.
22375. The speed of a rotary drum vacuum filter may be about __________ rpm.
22376. Colloid mills achieve size reduction mainly by
22377. Mesh indicates the number of holes per
22378. For achieving maximum capacity of the ball mill, the ball charge should be equal to about __________ percent of the ball mill volume.
22379. According to Bond crushing law, the work required to form particle of size 'D' from very large feed is (where (S/V)p and (S/V)f are surface to volume ratio of the product and feed respectively).
22380. Which of the following gives the work required for size reduction of coal to -200 mesh in a ball mill most accurately ?
22381. Electrical energy consumed by a jaw crusher is not a function of the
22382. Size reduction mechanism used in Jaw crushers is
22383. Trommels employ __________ for screening of materials.
22384. A widely used size reduction equipment for __________ is Bradford breaker.
22385. Ultra centrifuges are used for the separation of __________ solid particles.
22386. Specific surface area is the surface area of a unit __________ of materials.
22387. A. __________ mill is a revolving mill divided into two or more sections by perforated partitions in which preliminary grinding takes place at one end and the finishing grinding at the discharge end.
22388. The constants (Kb, Kr and Kk) used in the laws of crushing (i.e., Bond's law, Rittinger's law and Kick's law) depend upon the
22389. Size reduction does not occur due to compression in case of
22390. According to Taggart's rule for selecting between a gyratory crusher and a jaw crusher; the later should be used, if the hourly tonnage to be crushed divided by the square of the gape expressed in cm is less than
22391. Which of the following represents the plot of filtrate volume versus time for constant pressure filtration ?
22392. Driving force in case of filtration by a centrifuge is the
22393. Rod mills employed for grinding
22394. Production rate __________ with increased fineness, with a given energy input to the size reduction machine.
22395. Gold ore concentration is mostly done using
22396. Mixing of light fine powder such as insecticides is done by
22397. Run of mine (ROM) coal is crushed by a __________ for use in domestic ovens.
22398. Sphericity is the ratio of the surface area of a spherical particle having the same volume as the particle to the surface area of the particle. Which of the following has the maximum value of sphericity ?
22399. The unit of specific cake resistance is
22400. Size reduction of asbestos and mica is done by