A. Angle of repose is always greater than the angle of slide
B. A hopper is a small bin with a sloping bottom
C. A silo is a short height vessel of very large diameter used for the storage of high volatile
matter coal
D. Pine oil is used as a ‘modifying agent’ (for activating or depressing the adsorption of filming
agents) in froth floatation process
Related Mcqs:
- Pick out the correct statement ?
A. Plastic chips are called non-cohesive solids
B. Kick’s crushing law is, P/m = K . ln (D̅ sa/D̅ sb)
C. Communition is a generic term for size enlargement operation
D. Energy required in kwh per ton of product, such that 80% of it passes through a 200 mesh
screen, is called ‘Work index’ - Pick out the correct statement ?
A. Removal of iron from ceramic material is necessitated (by magnetic separation method) so as
to avoid discolouration of ceramic products
B. The operating cost of shaking screen is more than that of a vibrating screen
C. Screen capacity does not depend upon the specific gravity of the minerals
D. Asphalt is best crushed using toothed roll crusher - Pick out the correct statement?
A. The capacity and the effectiveness of a screen are the same
B. The capacity and the effectiveness of screen are opposing factors
C. The screening surface of a ‘reel’ (a revolving screen used in flour mills) is made of silk bolting
cloth supported by wire mesh
D. Both B. and C. - Pick out the wrong statement?
A. Cumulative analysis for determining surface area is preferred over differential analysis,
because of the assumption that “all particles in a simple fraction equal in size” is not needed
for cumulative analysis unlike differential analysis
B. A gate diagram is a plot of cumulative percent by weight undersize vs. the reciprocal of
diameter, in which the area beneath the curve represents the surface
C. Capacity of crusher in choke feeding is increased
D. Rolling of pebbles/balls from top to bottom of the heap in tumbling mills is called ‘cascading
and throwing of the balls through the air to the toe of the heap is called ‘cataracting’ - Pick out the wrong statement ?
A. More commonly used jaw crusher between Dodge jaw crusher and Blake jaw crusher is the
later one
B. There are only four methods namely compression, impact, attrition and cutting, which the size
reduction equipments employ
C. Cutting machines mainly employ ‘attrition’ for size reduction of solids
D. Operating principles of Dodge and Blake jaw crushers are combined in the working of
universal jaw crushers - Pick out the wrong statement ?
A. For the compressible cake, voidage & the specific resistance of the cake can be assumed to be
constant
B. Cake resistance is independent of the pressure drop
C. Crushing of explosive materials are done by employing dry-grinding
D. Gyratory crusher is a coarse crusher - Pick out the wrong statement pertaining to the roll crushers?
A. Maximum feed size determines the required roll diameter
B. For hard material’s crushing, the reduction ratio should not exceed 4
C. Both the rolls run necessarily at the same speed
D. Reduction ratio and differential roll speed affect production rate & energy consumed per unit
of surface produced - Pick out the wrong statement?
A. Recycled coarse material to the grinder by a classifier is termed as circulating load
B. Wear and tear in wet crushing is more than that in dry crushing of materials
C. Size enlargement (opposite of size reduction) is not a mechanical operation
D. A ‘dust catcher’ is simply an enlargement in a pipeline which permits the solids to settle down
due to reduction in velocity of the dust laden gas - Pick out the wrong statement ?
A. Gape is the greatest distance between the crushing surfaces or the jaws
B. The angle of nip (2α) is the angle between roll faces at the level where they will just take hold
of a particle and draw it in the crushing zone
C. Crushing efficiency is the ratio of the energy absorbed by the solid to the surfaces energy
created by crushing
D. Reduction ratio is the ratio of the maximum size of the particles in the feed to that in the
product - Pick out the wrong statement?
A. Close circuit grinding is more economical than open circuit grinding
B. Cod oil, beef tallow or aluminium stearates are used as grinding aids in cement ‘industries’
C. The equipment used for the removal of traces of solids from a liquid is called a classifier
D. Size enlargement is a mechanical operation exemplified by medicinal tablet making
