Which of the following is not a revolving/tumbling mill used for size reduction ?

Related Mcqs:

1. ______________ mill is not a revolving mill ?

   A. Pebble
   B. Compartment
   C. Cage
   D. Tube

2. A _____________ mill is a revolving mill divided into two or more sections by perforated partitions in which preliminary grinding takes place at one end and the finishing grinding at the discharge end?

   A. Compartment
   B. Tube
   C. Rod
   D. Pebble

3. In a ball mill, the volume occupied by the balls (when the mill is stopped) is about _______________ percent of the volume of the mill?

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

4. Pebble mills are tumbling mills widely used for grinding in the manufacture of paints & pigments and cosmetic industries, where iron contamination in the product is highly objectionable. Pebbles used in pebble mill are made of__________________?

   A. Bronze
   B. Stainless steel
   C. Flint or porcelain
   D. Concrete

5. In case of a revolving mill, wet grinding compared to dry grinding__________________?

   A. Requires more energy
   B. Has less capacity
   C. Complicates handling & classification of the product
   D. None of these

6. Wet grinding in a revolving mill ______________ as compared to dry grinding ?

   A. Gives less wear on chamber walls
   B. Requires more energy
   C. Increases capacity
   D. Complicates handling of the product

7. 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

8. Critical Speed (Nc) of a ball mill is given by (where R1 and R2 are radii of ball mill and the ball respectively) ?

   A. Nc = (1/4π). √(g/R1 – R2)
   B. Nc = (1/2π). √(g/R1 – R2)
   C. Nc = (1/π). √(g/R1 – R2)
   D. Nc = (1/2π). √(R1 – R2/g)

9. For achieving maximum capacity of the ball mill, the ball charge should be equal to about ______________ percent of the ball mill volume?

   A. 10
   B. 25
   C. 50
   D. 75

10. Power required to drive a ball mill with a particular ball load is proportional to (where, D = diameter of ball mill.) ?

    A. D
    B. 1/D
    C. D2.5
    D. 1/D2.5