Removal of iron from ceramic material is necessitated (by magnetic separation method) so as to avoid discolouration of ceramic products
The operating cost of shaking screen is more than that of a vibrating screen
Screen capacity does not depend upon the specific gravity of the minerals
Asphalt is best crushed using toothed roll crusher
Correct answer: (A) Removal of iron from ceramic material is necessitated (by magnetic separation method) so as to avoid discolouration of ceramic products
222. Pick out the material having minimum Rittinger's number.
Calcite
Pyrite
Quartz
Galena
Correct answer: (C) Quartz
223. Pick out the wrong statement pertaining to the roll crushers.
Maximum feed size determines the required roll diameter
For hard material's crushing, the reduction ratio should not exceed 4
Both the rolls run necessarily at the same speed
Reduction ratio and differential roll speed affect production rate & energy consumed per unit of surface produced
Correct answer: (C) Both the rolls run necessarily at the same speed
224. Pick out the wrong statement pertaining to the turbine agitator.
Recommended peripheral speed for the turbine agitator is 200-250 metres/minute
Pitched blade turbine agitator gives only radial flow with complete absence of the axial flow
Generally, the diameter of the agitator is kept between l/3rd to l/6th of the tank diameter while the blade length is l/4th of agitator diameter (with central disc, it is l/8th of the agitator diameter)
Turbine agitator should be located at a height not less than one agitator diameter length from the bottom. If the depth of liquid in the tank is more than twice the agitator diameter, two agitators should be used
Correct answer: (B) Pitched blade turbine agitator gives only radial flow with complete absence of the axial flow
225. Pick out the wrong statement.
For the compressible cake, voidage & the specific resistance of the cake can be assumed to be constant
Cake resistance is independent of the pressure drop
Crushing of explosive materials are done by employing dry-grinding
Gyratory crusher is a coarse crusher
Correct answer: (B) Cake resistance is independent of the pressure drop
226. Pick out the wrong statement:
Magnetic separation method can be employed to treat both dry & wet ores
Reduction ratio in crushing operation is defined as the ratio of minimum feed size to the maximum product size
Gyratory crusher is used for coarse crushing
Screens are of stationary, moving and vibratory types
Correct answer: (B) Reduction ratio in crushing operation is defined as the ratio of minimum feed size to the maximum product size
227. Pine oil and Cresylic acid are used as _________ in the froth floatation process.
Frother
Collector
Depressor
Conditioner
Correct answer: (A) Frother
228. Pine oil used in froth floatation technique acts as a/an
Collector
Modifier
Frother
Activator
Correct answer: (C) Frother
229. Power consumption during turbulent flow in agitation tank is proportional to the _________ of the liquid.
Viscosity
Thermal conductivity
Surface tension
Density
Correct answer: (D) Density
230. Power required to drive a ball mill with a particular ball load is proportional to (where, D = diameter of ball mill.)