Mechanical Operations Rittinger's crushing law states that Work required to form a particle of any size is proportional to the square of the surface to volume ratio of the product Work required in crushing is proportional to the new surface created For a given machine and feed, crushing efficiency is dependent on the size of the feed & product Work required to form a particle of a particular size is proportional to the square root of the surface to volume ratio of the product Work required to form a particle of any size is proportional to the square of the surface to volume ratio of the product Work required in crushing is proportional to the new surface created For a given machine and feed, crushing efficiency is dependent on the size of the feed & product Work required to form a particle of a particular size is proportional to the square root of the surface to volume ratio of the product ANSWER DOWNLOAD EXAMIANS APP
Mechanical Operations Tube mill compared to ball mill Produces finer products Is long in comparison with its diameter All of these Uses smaller balls Produces finer products Is long in comparison with its diameter All of these Uses smaller balls ANSWER DOWNLOAD EXAMIANS APP
Mechanical Operations Actual operating speed of a ball mill may vary from 65 to 80% of the critical speed. Which of the following duties would require the ball mill to be operated at maximum percentage of critical speed? Wet grinding in high viscous suspension Dry grindng of large particles in un-baffed mills Wet grinding in low viscous suspension Dry grinding of large particles (upto 1.25 cms) Wet grinding in high viscous suspension Dry grindng of large particles in un-baffed mills Wet grinding in low viscous suspension Dry grinding of large particles (upto 1.25 cms) ANSWER DOWNLOAD EXAMIANS APP
Mechanical Operations During the washing of cake Filter medium resistance decreases Cake resistance decreases All the resistances are constant Filter medium resistance increases Filter medium resistance decreases Cake resistance decreases All the resistances are constant Filter medium resistance increases ANSWER DOWNLOAD EXAMIANS APP
Mechanical Operations The specific cake resistance for incompressible sludges is (where ΔP = pressure drop over cake) ∝ 1/ ΔP ∝ ΔP Independent of ΔP ∝ √ΔP ∝ 1/ ΔP ∝ ΔP Independent of ΔP ∝ √ΔP ANSWER DOWNLOAD EXAMIANS APP
Mechanical Operations The specific surface of spherical particles is given by (where D and ρ are diameter and density of particle). 12/D.p 6/D.p 4/D.p 2/D.p 12/D.p 6/D.p 4/D.p 2/D.p ANSWER DOWNLOAD EXAMIANS APP
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