### Ball Mill Operating Speed Mechanical Operations Solved

The critical speed of ball mill is given by where r radius of ball mill r radius of ball for r 1000 mm and r 50 mm n c 307 rpm but the mill is operated at a speed of 15 rpm therefore the mill is operated at 100 x 15307 4886 of critical speed if 100 mm dia balls are replaced by 50 mm dia balls and the other conditions