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Chemical Engineering :: Mechanical Operations

  1. Cement clinker is reduced to fine size by a

  2. A.
    roll crusher
    B.
    ball mill
    C.
    tube mill
    D.
    hammer mill

  3. The crushed material received for separation is called feed or

  4. A.
    tailing
    B.
    heading
    C.
    concentrate
    D.
    middling

  5. For spheres, volume shape factor is given by

  6. A.
    π(=A/D2)
    B.
    2π(=2A/D2)
    C.
    π/6(=V/D3)
    D.
    AD/V

  7. Which of the following agitators having a large blade area, rotating at slow speed is used for mixing high viscosity liquids ( > 50000 centipoise) ?

  8. A.
    Propeller
    B.
    Helical screw
    C.
    Flat blade turbine
    D.
    Curved blade turbine

  9. __________ is defined as the geometric mean of the relative rejections and the relative recoveries of two minerals.

  10. A.
    Separation efficiency
    B.
    Selectivity index
    C.
    Concentration ratio
    D.
    none of these

  11. The operating speed of a ball mill should be __________ the critical speed.

  12. A.
    less than
    B.
    much more than
    C.
    at least equal to
    D.
    slightly more than

  13. Use of baffles in agitators help in minimising the __________ tendency.

  14. A.
    swirling
    B.
    vortexing
    C.
    both (a) & (b)
    D.
    neither (a) nor (b)

  15. __________ are used for the separation of coarse particles from a slurry of fine particles.

  16. A.
    Thickeners
    B.
    Classifiers
    C.
    Hydrocyclones
    D.
    Decanters

  17. Fibrous material is broken by a

  18. A.
    rollcrusher
    B.
    squirrel-cage disintegrator
    C.
    ball mill
    D.
    tube mill

  19. __________ is the most suitable for compounding rubber and plastic solids.

  20. A.
    Banbery mixer
    B.
    Pan mixer
    C.
    Pug mill
    D.
    Charge can mixer