In a grinding operation, the limiting particle size is the size of the _______________ particle in the sample?

Related Mcqs:

1. Use of ‘grinding aids’ is done in _______________ grinding?

   A. Dry
   B. Wet
   C. Ultrafine
   D. Intermediate

2. Number of particles in a crushed solid sample is given by (where, m = mass of particles in a sample, Vp = volume of one particle, ρ= density of particles) ?

   A. m/ρ . Vp
   B. m . ρ/Vp
   C. m . Vp/ρ
   D. Vp/m . ρ

3. Sphericity for a non-spherical particle is given by (where, V and S are volume and surface area respectively of one particle. and, D = equivalent diameter of particle)?

   A. 6.V/D.S
   B. V/6D.S
   C. D.S/V
   D. V/D.S

4. Sphericity is the ratio of the surface area of a spherical particle having the same volume as the particle to the surface area of the particle. Which of the following has the maximum value of sphericity ?

   A. Sphere
   B. Cube
   C. Cylinder (L/D = 1)
   D. Raschig rings

5. Which of the following grinding mills has the horizontally arranged rods as the grinding elements thereby delivering more uniform granular products with minimum fines ?

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

6. The value of work index does not change materially from one equipment to another. If the value of work index determined for close circuit grinding is Wi, then the same for open circuit grinding will be_________________?

   A. 0.5 Wi
   B. Wi
   C. 1.34 Wi
   D. 3.34 Wi

7. Work index is the gross energy (kWh/tonne of feed) necessary to reduce a very large feed to such a size that 80% of product particles will pass through a 0.1 mm screen. The value of work index determined for wet grinding should be multiplied with ______________ to get the same for dry grinding?

   A. 1.0
   B. 0.5
   C. 1.34
   D. 4.34

8. 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

9. 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

10. In closed circuit grinding as compared to open circuit grinding, the_________________?

    A. Specific surface of product is more
    B. Product has lesser size uniformity
    C. Production rate at a given limiting size is lower
    D. Operation is economical