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

Related Mcqs:

1. Which of the following is not accomplished by agitation of liquids in agitators ?

   A. Dispersing gas in liquid
   B. Blending of immiscible liquids
   C. Dispersing immiscible liquid in form of emulsion
   D. Suspending solid particles

2. Velocity of a small particle of diameter ‘Dp’ at a distance ‘r’ from the rotational axis of a cyclone rotating at an angular speed ‘ω’ is given by (the other symbols are as per standard notation) ?

   A. [(DP/18). (ρs – ρ/μ)] ω2r
   B. [(DP2/18). (ρs – ρ/μ)] ω2r
   C. [(DP/18). (ρs – ρ/μ)] ω2r2
   D. [(DP2/18). (ρs – ρ/μ)] ω2r

3. Use of baffles in agitators help in minimising the ______________ tendency?

   A. Swirling
   B. Vortexing
   C. Both A. & B.
   D. Neither A. nor B.

4. Actual operating speed of a ball mill may vary from 65 to 80% of the critical speed. Which of the following duties would require the ball mill to be operated at maximum percentage of critical speed ?

   A. Wet grinding in low viscous suspension
   B. Wet grinding in high viscous suspension
   C. Dry grinding of large particles (upto 1.25 cms)
   D. Dry grinding of large particles in un-baffed mills

5. Which of the following clay mixing devices is vacuum operated for deairation of clay ?

   A. Banbury mixer
   B. Pug mill
   C. Muller-mixer
   D. None of these

6. Optimum ratio of operating speed to critical speed of a trommel is_____________________?

   A. 0.33-0.45
   B. 1.33-1.45
   C. 0.5-2
   D. 1.5-2.5

7. The operating speed of a ball mill should be ______________ the critical speed?

   A. Less than
   B. Much more than
   C. At least equal to
   D. Slightly more than

8. Which of the following may prove unsuitable for filtering volatile liquids ?

   A. Pressure filter
   B. Gravity filter
   C. Centrifugal filter
   D. Vacuum filter

9. Which of the following is not used as a filter medium in case of corrosive liquids?

   A. Nylon
   B. Glass cloth
   C. Metal cloth of monel or stainless steel
   D. Cotton fabric

10. The energy required per unit mass to grind limestone particles of very large size to 100 μm is 12.7 kWh/ton. An estimate (using Bond’s law) of the energy to grind the particles from a very large size to 50 μm is________________?

    A. 6.35 kWh/ton
    B. 9.0 kWh/ton
    C. 18 kWh/ton
    D. 25.4 kWh/ton