A. Gross energy (kWh/ton of feed) needed to reduce very large feed to such a size that 80% of
the product passes through a 100 micron screen
B. Energy needed to crush one tonne of feed to 200 microns
C. Energy (kWh/ton of feed) needed to crush small feed to such a size that 80% of the product
passes a 200 mesh screen
D. Energy needed to crush one ton of feed to 100 microns
Related Mcqs:
- 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 - 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 - The work index in Bond’s law for crushing of solids has the following dimensions__________________?
A. No units (dimensionless)
B. kWh/ton
C. kW/ton
D. kWh.m1/2/ton - During agitation of liquids, the_________________?
A. Froude number is independent for the curves between power number and Reynolds number in
baffled system
B. Power number becomes independent of impellers Reynolds number at high Reynolds number,
but is dependent on the geometry of the impeller
C. Froude number is used to account for the effect of surface (e.g., the centre vortex) on the
power number
D. All A., B. and C. - If radius of a batch basket centrifuge is halved & the r.p.m. is doubled, then the_________________?
A. Linear speed of the basket is doubled
B. Linear speed of the basket is halved
C. Centrifugal force is doubled
D. Capacity of centrifuge is increased - Weber number is significant and is concerned with the_________________?
A. Solid-liquid mixing
B. Liquid-liquid mixing
C. Dispersion of liquid in liquid
D. Suspension of solid in liquid - In a roll crusher, the specific power consumption and the production rate is affected by the_________________?
A. Reduction ratio
B. Differential roll speed
C. Both A. and B.
D. Neither A. nor B. - A compressible cake has the_________________?
A. Maximum porosity at the upstream side
B. Maximum porosity at the filter medium
C. Same porosity throughout the cake thickness
D. None of these - Filtration should be stopped in a filter press, if the_________________?
A. Cake becomes very dense
B. Liquor stops flowing out to the discharge
C. Filtration pressure rises suddenly
D. Both B. & C. - 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
