Sizing of very fine particles of the order of 5 to 10 microns is done by elutriation, which is a _____________ operation?

Related Mcqs:

1. For sizing of fine materials, the most suitable equipment is a____________________?

   A. Trommel
   B. Grizzly
   C. Shaking screen
   D. Vibrating screen

2. ______________ are used for the separation of coarse particles from a slurry of fine particles?

   A. Thickeners
   B. Classifiers
   C. Hydrocyclones
   D. Decanters

3. 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

4. For Indian standard (IS) screens, the mesh number is equal to its aperture size expressed to the nearest deca-micron (0.01 mm). Aperture width of IS screen of mesh number 50 will be approximately _____________ microns?

   A. 5
   B. 50
   C. 500
   D. 5000

5. 200 mesh sieve size corresponds to _____________ microns?

   A. 24
   B. 74
   C. 154
   D. 200

6. What is the reduction ratio in a fine crushing operation having following feed and product sizes ?

   A. 0.5
   B. 2
   C. 5
   D. 10

7. The energy required per unit mass to grind limestone particles of very large size to 100 μm is 12.7 kWh/ton. An estimate (using Bond’s law) of the energy to grind the particles from a very large size to 50 μm is________________?

   A. 6.35 kWh/ton
   B. 9.0 kWh/ton
   C. 18 kWh/ton
   D. 25.4 kWh/ton

8. Mixing of light fine powder such as insecticides is done by____________________?

   A. Banbury mixer
   B. Pug mill
   C. Impact wheels
   D. Kneader

9. Particle size range in which dust catcher (gravity settling chamber) works most effectively and efficiently is ______________ microns?

   A. < 5
   B. 10 to 25
   C. < 74
   D. > 1000

10. Ultra centrifuges are used for the separation of _____________ solid particles?

    A. Coarse
    B. Fine
    C. Colloidal
    D. Dissolved