2012 12 9 Show The Critical Speed Of Ball Mill Derivation critical speed of ball mill formula and derivation findings show that there is a Calculate critical speed 3 Live Chat Ball mill Critical speed can be Aside from common ball mills there is a second type of ball mill called a planetary ball mill Planetary ball mills are smaller than. Critical Speed Of Ball Mill Formula Derivation. 201983 the formula to calculate critical speed is given below. n c 42.305 sqtdd n c critical speed of the mill. d mill diameter specified in meters. d diameter of the ball. in practice ball mills are driven at a speed of 5090 of the critical speed, the factor being influenced by economic consideration.