### Ball Mills - an overview | ScienceDirect Topics

The critical speed n (rpm) ... It is possible to make an approximate calculation of the capacity of a ball mill with uneven armor by means of the equation: N = 0.104 D 3 L ρ b. a p φ 0.88 + 0.1 L n 1 η 1 η 2. where D is the drum diameter, L is the drum length, ρ b.ap is the apparent density of the balls, φ is the degree of filling of the mill by balls, n is the revolutions per minute ...