Study On The Modeling Simulation And Experiment Of Dual-planetary Ball Mill Based On Discrete Element Method

As the main equipment of grinding mill,ball mill has always been highly regarded by researchers. A variety of new grinding equipment continue to emerge, but the research of relevant theory is relatively slow. This paper studied on dual-planetary ball mill which is a new kind of ball mill.Reasearch of the law of motion of medium and the realation between the working parameters with the grinding ability in dual planetary ball mill has important significance for the development of this kind of equipment.The law of motion of balls that explains the work principles of dual-planetary ball mill was obtained by theoretical anlaysising and discrete element simulation in PFC3D.The best range of working parameters was obtained by simulation and experiment of grinding copper mine. The simulation of scale-up dual-planetary ball mill can provide a reference for the widely application in factories.Discrete element method is seldom used in unconventional ball mill, this paper uses dynamic simulation software solving the motion data of dual-planetary ball mill, which was successfully applied in PFC3D discrete element modeling to simulate the complex movement of dual-planetary ball mill.This modeling processing can overcome the disadvantages of the PFC3D,and provides a reference for discrete element modeling on relevant aspects. The main conclusions in this paper are:l.The motion of balls in dual-planetary ball mill can be conclused as three stages:centrifugal motion, off motion,centrifugal motion.The off motion occurred when the milling tank farthest from the center of the ball mill,the materials can be grinded by the balls in this stage.2.The mean contact force of balls increases linearly with rotation speed,the impact energy increases cubic with rotation speed,the rotation speed of dual-planetary ball mill in this paper should be obtained over150r/min to ensure the balls can grind materials. The production rate increases rapidly with increasing of rotation speed,the growth of production rate becomes slow when the production rate reaches55%. The mean contact force and the impact energy of balls decreases with the increasing of filling rate.High filling rate would cause most of balls always keeping in centrifugal motion state so the materials cannot be grinded, the best filling rate of the dual-planetary ball mill in this paper is about20%. The production rate of powder decreases with the increasing of filling rate. The mean contact force of balls increases linearly with the diameter of ball,and the impact energy decreases linearly.The production rate of powder achieves maximum when the diameter of ball was8mm in this paper. Milling pot shape design must be considered both height and diameter, the optimal design diameter of mill pot in this paper is (35～40) mm.