For efficient grinding, ball mills must be operated__________________?

Which of the following is not used as filter aid ?

A. Asbestos

B. Diatomaceous earth

C. Purified wood cellulose

D. Rice husk

Which of the following mechanical conveyors does not come under the division „carriers‟ ?

A. Belt conveyor

B. Bucket elevator

C. Screw conveyor

D. Apron conveyor

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

Height of liquid in agitation tank is normally maintained equal to the tank diameter. However, if the tank is too tall and a large liquid hold up is desired, then two or more impellers mounted on the same shaft may be used. The clearance between the tank bottom and the bottom most impeller should be about (where, D = impeller diameter) ?

A. 0.5 D

B. D

C. 1.5 D

D. 2 D

Angle of nip of the crushing rolls does not depend upon the_______________?

A. Diameter of the rolls

B. Speed of the rolls

C. Product size

D. Feed size