type of grinding media (balls, rods, cylinders, rings, etc.), mill rotation speed, vibration amplitude and milling dura-tion (Karinkanta et al. 2013, 2014; Kim et al. 2013). The velocity of a rotary ball mill is limited by its critical speed, thus the size reduction rate is much lower than that of a planetary ball mill (Schwanninger et al. 2004 ...Web