101. What is the selectivity index, if the grade of tailings & concentrate is the same ?
102. The most suitable equipment used to devulcanise rubber scrap and to make water dispersion & rubber solution is a
103. Traces of solids are removed from, liquid in a
104. __________ balls capable of grinding the feed in a ball mill gives the maximum efficiency.
105. The speed of a rotary drum vacuum filter may be about __________ rpm.
106. Colloid mills achieve size reduction mainly by
107. Mesh indicates the number of holes per
108. For achieving maximum capacity of the ball mill, the ball charge should be equal to about __________ percent of the ball mill volume.
109. 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).
110. Which of the following gives the work required for size reduction of coal to -200 mesh in a ball mill most accurately ?
111. Electrical energy consumed by a jaw crusher is not a function of the
112. Size reduction mechanism used in Jaw crushers is
113. Trommels employ __________ for screening of materials.
114. A widely used size reduction equipment for __________ is Bradford breaker.
115. Ultra centrifuges are used for the separation of __________ solid particles.
116. Specific surface area is the surface area of a unit __________ of materials.
117. 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.
118. 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
119. Size reduction does not occur due to compression in case of
120. 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
121. Which of the following represents the plot of filtrate volume versus time for constant pressure filtration ?
122. Driving force in case of filtration by a centrifuge is the
123. Rod mills employed for grinding
124. Production rate __________ with increased fineness, with a given energy input to the size reduction machine.