Related Mcqs:

1. 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)

2. 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

3. 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

4. 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

5. 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

6. Tube mill compared to ball mill_______________________?

   A. Produces finer products
   B. Is long in comparison with its diameter
   C. Uses smaller balls
   D. All A., B. & C.

7. A tube mill as compared to a ball mill__________________?

   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.

8. A tube mill compared to a ball mill__________________?

   A. Has a higher length/diameter ratio
   B. Produces a coarser product
   C. Has a higher diameter/length ratio
   D. Uses much larger balls

9. Crushing of mineral particles is accomplished in a ‘cage mill’, when one or more alloy steel bars are revolved in opposite directions. It is a type of ______________ mill?

   A. Impact
   B. Roll
   C. Vibratory
   D. None of these

10. 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