_____________________ baffles are provided in ball mills ?

Related Mcqs:

1. Ball mills and tube mills with flint or porcelain balls are used for size reduction of_______________?

   A. Asbestos
   B. Rubber
   C. Non-metallic ores
   D. Limestone

2. Size reduction of the ______________ can be suitably done by ball mills, crushing rolls and rod mills?

   A. Metalliferous ores
   B. Non-metallic ores
   C. Basic slags
   D. Asbestos & mica

3. ____________ mills fall in the category of tumbling mills ?

   A. Ball and pebble
   B. Rod and tube
   C. Compartment
   D. All A., B. & C.

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. 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)

6. 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

7. 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

8. For efficient grinding, ball mills must be operated__________________?

   A. At a speed less than the critical speed
   B. At a speed more than the critical speed
   C. At a speed equal to the critical speed
   D. With minimum possible small balls

9. Balls for ball mills are never made of_________________?

   A. Forged/cast steel
   B. Lead
   C. Cast iron
   D. Alloy steel

10. 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