equation Of critical speed In ball mill. derivation of critical speed in a ball mill pdf youtube. may 24, 2018 critical speed the critical speed nc is the speed, where the centrifugal force at the mill lining is equal to the gravitational force normal mill speeds are 80% of the critical speed.materials science and engineering 381 can be ... Variables in Ball Mill Operation Paul O Abbe Critical speed (CS) is the speed at which the grinding media will centrifuge against the wall of the cylinder Obviously no milling will occur when the media is pinned against the cylinder so operating speed will be some percentage of the CS The formula for critical speed is CS 1/2 (g/(Rr) where g is the gravitational constant, R is derive ...