### Ball Mills an overview | ScienceDirect Topics

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