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1) The process by which fine solids is removed from liquids is termed as _____________________? a. Decantation b. Flocculation c. Sedimentation d. Classification
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2) Which of the following is the hardest material ? a. Calcite b. Quartz c. Corundum d. Gypsum
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3) In constant pressure filtration ? 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
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4) Use of ‘grinding aids’ is done in _______________ grinding? a. Dry b. Wet c. Ultrafine d. Intermediate
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5) Which of the following crushing laws is most accurately applicable to the fine grinding of materials ? a. Bond’s crushing law b. Kick’s law c. Rittinger’s law d. None of these
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6) _______________ is a cohesive solid ? a. Wheat b. Sand c. Wet clay d. None of these
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7) Pine oil used in froth floatation technique acts as a/an_____________________? a. Collector b. Modifier c. Frother d. Activator
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8) Raw materials are charged in the iron blast furnace using____________________? a. Bucket elevator b. Skip hoist c. Screw conveyor d. None of these
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9) Solid particles of different densities are separated by _____________________? a. Filters b. Thickness c. Cyclones d. Sorting classifier
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10) Moore filter is a ______________ filter ? a. Leaf b. Press c. Rotary d. Sand
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11) In coal washeries, three products namely the valuable product (i.e. clean/washed coal), discarded product (i.e. mineral matter) and an additional concentrated product called _____________ is produced? a. Concentrate b. Tailing c. Middling d. None of these
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12) During agitation of liquids, power consumption during laminar flow is not proportional to the ________________? a. Density of the liquid b. Viscosity of the liquid c. Cube of impeller diameters d. Square of rotational speed
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13) The main differentiation factor between tube mill and ball mill is the ___________________? a. Length to diameter ratio b. Size of the grinding media c. Final product size d. Operating speed
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14) For sizing of fine materials, the most suitable equipment is a____________________? a. Trommel b. Grizzly c. Shaking screen d. Vibrating screen
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15) The specific surface of spherical particles is given by (where D and ρ are diameter and density of particle) ? a. 6/D.ρ b. 2/D.ρ c. 4/D.ρ d. 12/D.ρ
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16) Trommels are revolving screens which normally operate in the range of _______________ rpm? a. 1 – 2 b. 15 – 20 c. 40 – 50 d. 60 – 75
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17) Filter aids like asbestos, kieselguhr, diatomaceous earth etc. are used to increase the porosity of the final filter cake & reducing the cake resistance during filtration. Filter aid is_______________? a. Added to the feed slurry b. Pre-coated on the filter medium prior to filtration c. Separated from the cake by dissolving solids or by burning it off d. All A, B. & C.
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18) Ultracentrifuges running at speeds upto 100000 rpm is normally used for the_____________________? a. Separation of isotopes based on their density or molecular weights difference b. Concentration of rubber latex c. Separation of cream from milk d. Dewaxing of lubricating oil
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19) Maximum size reduction in a fluid energy mill is achieved by___________________? a. Compression b. Interparticle attrition c. Cutting d. Impact
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20) Which of the following is not a wet classifier ? a. Sharpies super-centrifuge b. Hydrocyclones c. Dorr Oliver rake classifier d. None of these
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21) Size reduction of fibrous materials like wood, asbestos, mica etc. is done by a disintegrator exemplified by the _________________? a. Blake jaw crusher b. Cage mill c. Stamp mill d. Bradford’s breaker
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22) Specific surface area is the surface area of a unit _______________ of materials? a. Weight b. Volume c. Either A. or B. d. Neither A. nor B.
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23) Separation of a suspension or slurry into a supernatant clear liquid (free from particles) and a thick sludge containing a high concentration of solid is called__________________? a. Classification b. Sedimentation c. Clarification d. Decantation
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24) If a force greater than that of gravity is used to separate solids & fluids of different densities, the process is termed as the __________________? a. Sedimentation b. Flocculation c. Dispersion d. Centrifugation
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25) The ratio of the actual mesh dimension of Taylor series to that of the next smaller screen is_______________? a. 2 b. √2 c. 1.5 d. √3
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26) The energy consumed by a ball mill depends on__________________? a. Its speed b. Its ball load c. The density of the material being ground d. All A., B. and C.
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27) Size reduction of asbestos and mica is done by____________________? a. Hammer mills b. Rod mills c. Gyratory crushers d. Crushing rolls
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28) In case of a hammer crusher, the final product size depends on the____________________? a. Feed rate b. Rotor speed c. Clearance between hammer & grinding plates d. All A., B. and C.
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29) Tube mill compared to ball mill_______________________? a. Produces finer products b. Is long in comparison with its diameter c. Uses smaller balls d. All A., B. & C.
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30) Tabling process used for separating two materials of different densities by passing the dilute pulp over a table/deck, which is inclined from the horizontal surface at an angle of about________________? a. 1 to 2° b. 2 to 5° c. 5 to 10° d. 10 to 15°
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