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  • Question
  • Length/diameter ratio of a ball mill is


  • Options
  • A. 1.5
  • B. 1
  • C. < 1
  • D. > 1

  • Correct Answer
  • < 1 


  • Mechanical Operations problems


    Search Results


    • 1. Basic slag is not ground in

    • Options
    • A. jaw crushers
    • B. ball mills
    • C. compartment mills
    • D. tube mills
    • Discuss
    • 2. For spheres, volume shape factor is given by

    • Options
    • A. ?(=A/D2)
    • B. 2?(=2A/D2)
    • C. ?/6(=V/D3)
    • D. AD/V
    • Discuss
    • 3. Coal is finally pulverised to 200 mesh size for burning in boilers by a

    • Options
    • A. hammer crusher
    • B. ball mill
    • C. roll crusher
    • D. gyratory crusher
    • Discuss
    • 4. Which of the following agitators having a large blade area, rotating at slow speed is used for mixing high viscosity liquids ( > 50000 centipoise)?

    • Options
    • A. Propeller
    • B. Helical screw
    • C. Flat blade turbine
    • D. Curved blade turbine
    • Discuss
    • 5. The controlling resistance in a rotary drum vacuum filter is the __________ resistance.

    • Options
    • A. piping
    • B. cake
    • C. filter medium
    • D. none of these
    • Discuss
    • 6. A tube mill as compared to a ball mill

    • Options
    • A. employs smaller balls.
    • B. gives finer size reduction but consumes more power.
    • C. has larger length/diameter ratio (>2 as compared to 1 for ball mill).
    • D. all (a), (b) and (c).
    • Discuss
    • 7. Bucket elevators are not suitable for the vertical lifting of __________ materials.

    • Options
    • A. fine (e.g. - 200 mesh size coal)
    • B. sticky (e.g. clay paste)
    • C. small lumpy (e.g. grains and sand)
    • D. free flowing
    • Discuss
    • 8. Traces of solids are removed from, liquid in a

    • Options
    • A. classifier
    • B. clarifier
    • C. sparkler filter
    • D. rotary vacuum filter
    • Discuss
    • 9. Driving force in case of filtration by a centrifuge is the

    • Options
    • A. speed of the centrifuge.
    • B. centrifugal pressure exerted by the liquid.
    • C. narrow diameter of the vessel.
    • D. formation of highly porous cake.
    • Discuss
    • 10. Addition of filter aid to the slurry before filtration is done to ...... of the cake.

    • Options
    • A. increase the porosity
    • B. increase the compressibility co-efficient
    • C. decrease the porosity
    • D. decrease the compressibility co-efficient
    • Discuss


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