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Chemical Engineering :: Mechanical Operations

  1. Cyclones are used primarily for separating

  2. A.
    solids
    B.
    solids from fluids
    C.
    liquids
    D.
    solids from solids

  3. There is practically no alternative/competitor to __________ in the beneficiation treatment of sulphide ores.

  4. A.
    classification
    B.
    tabling
    C.
    jigging
    D.
    froth floatation

  5. Separation of isotopes is generally done using a/an __________ centrifuge.

  6. A.
    ultra
    B.
    disk-bowl
    C.
    both (a) & (b)
    D.
    neither (a) nor (b)

  7. Temperature of the product during ultrafine grinding

  8. A.
    increases
    B.
    decreases
    C.
    remains constant
    D.
    may increase or decrease ; depends on the material being ground

  9. Reciprocating screens are normally inclined at an angle of 5° with the horizontal and employ gyratory motion at feed end & reciprocating motion at the discharge end. They are not suitable for the screening of the

  10. A.
    light metal powder down upto 4 meshsize.
    B.
    dry chemicals.
    C.
    heavy tonnages of rocks or gravel.
    D.
    powdered food & granular materials.

  11. In a ball mill, the volume occupied by the balls (when the mill is stopped) is about __________ percent of the volume of the mill.

  12. A.
    35
    B.
    50
    C.
    70
    D.
    85

  13. Separation of materials of the same density based on their sizes by using then-different rates of flow is called

  14. A.
    sorting
    B.
    sizing
    C.
    flocculation
    D.
    elutriation

  15. Molten ammonium nitrate is mixed with ground limestone in fertilizer plant in a

  16. A.
    pug mill
    B.
    mixer-extruder
    C.
    banbury mixer
    D.
    muller mixer

  17. Agglomeration of individual particles into clusters (flocs) is called flocculation. To prevent flocculation, the most commonly used dispersing agents are

  18. A.
    carbonates
    B.
    sulphates
    C.
    silicates & phosphates
    D.
    bi-carbonates

  19. For a sphere falling in the constant drag co-efficient regime, its terminal velocity depends on its diameter (d) as

  20. A.
    d
    B.
    d
    C.
    d2
    D.
    1/d