Ultrafine grinders operate principally by_________________?

Related Mcqs:

1. The main size reduction operation in ultrafine grinders is_____________?

   A. Cutting
   B. Attrition
   C. Compression
   D. Impact

2. The reduction ratio for grinders is defined as (where, Df and Dp are average diameters of feed and product respectively) ?

   A. Df/Dp
   B. Dp/Df
   C. Df – Dp
   D. None of these

3. The reduction ratio for fine grinders is_____________?

   A. 5-10
   B. 10-20
   C. 20-40
   D. As high as 100

4. Which of the following size reduction equipments employs mainly attrition for ultrafine grinding ?

   A. Jet mills
   B. Fluid energy mill
   C. Micronizer
   D. All A., B. and C.

5. Size measurement of ultrafine particles can be best expressed in terms of___________________?

   A. Centimetre
   B. Screen size
   C. Micron
   D. Surface area per unit mass

6. To get ultrafine particles, the equipment used is a _________________?

   A. Ball mill
   B. Rod mill
   C. Hammer crusher
   D. Fluid energy mill

7. Which of the following is not an ultrafine grinder (colloid mill) ?

   A. Micronizers
   B. Agitated mills and fluid energy mills
   C. Toothed roll crusher
   D. Hammer mills with internal classification

8. Temperature of the product during ultrafine grinding_____________________?

   A. Increases
   B. Decreases
   C. Remain constant
   D. May increase or decrease; depends on the material being ground

9. For the transportation of ultrafine particles, the equipment used is a ____________ conveyor?

   A. Belt
   B. Pneumatic
   C. Screw
   D. None of these

10. Trommels are revolving screens which normally operate in the range of _______________ rpm?

    A. 1 – 2
    B. 15 – 20
    C. 40 – 50
    D. 60 – 75