Energy consumed for crushing one ton of material ranges from ______________ kWh?

Related Mcqs:

1. 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

2. 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

3. In a size reduction crushing operation, feed size is 300 to 1500 mm while the product size is 100 to 300 mm. This is a case of the ________________ crushing?

   A. Secondary
   B. Fine
   C. Primary
   D. Ultrafine

4. In a size reduction crushing operation, feed size is 100 to 300 mm. while the product size is 10 to 50 mm. This is a case of the _____________ crushing?

   A. Primary
   B. Secondary
   C. Fine
   D. Ultrafine

5. General crushing equation is given by d(P/m) = -K (dD̅ S/D̅ n S). Bond’s crushing law is obtained by solving this equation for n = _____________ and feed of infinite size?

   A. 1
   B. 1.5
   C. 2
   D. 2.5

6. In a size reduction crushing operation, the feed size is 10 to 50 mm, while the product size is 2 to 10 mm. This is a case of _______________ crushing?

   A. Primary
   B. Secondary
   C. Fine
   D. Ultrafine

7. What is the usual value of angle of nip for crushing of ordinary rock in smooth steel crushing rolls?

   A. 16°
   B. 32°
   C. 40°
   D. 46°

8. For crushing of solids, the Rittinger’s law states that the work required for crushing is proportional to __________________?

   A. The new surface created
   B. The size reduction ratio
   C. The change in volume due to crushing
   D. None of these

9. Crushing efficiency of a machine ranges between __________________ percent?

   A. 0.1 to 2
   B. 5 to 10
   C. 20 to 25
   D. 50 to 70

10. The energy consumed by a ball mill depends on__________________?

    A. Its speed
    B. Its ball load
    C. The density of the material being ground
    D. All A., B. and C.