Research On Tumbling Mill Based On Technology Of Discrete Element Method

Tumbling mill is the primarily equipment of fine grinding, which is widely used in the fields of mine, medicine, food, ceramics, metallurgy, cement, etc.. Because the tumbling mill is limited by the grinding particle size and the speed of cylinder, it leads to the low grinding efficiency of the material, thus limiting the processing efficiency of the whole product. Therefore, how to improve the working efficiency of the tumbling mill has become a subject of great research value. After 100 years of development, tumbling mill developed constantly to the direction of large-scale, and the structure of tumbling mill is also more complex and precision, in order to improve work efficiency of the tumbling mill.Many researchers at home and abroad have made a lot of improvements on the structure of the tumbling mills, such as super critical speed tumbling mill, stirring tumbling mill and so on and carried out a lot of research on tumbling mill. Researches mainly focus on the influencing factors of grinding efficiency and grinding particle size such as the movement law of particles in the mill, the energy distribution, stress distribution and the shape of lifter and grinding media the diameter and rotational speed of cylinder. Assumptions and analysis on the improvement of the mill in theory have been made. And the research of the content of the ball mill constantly will be enriched.The tumbling mill of MQZ Φ1.2m×2.4m is treated as the research object. The motion law of grinding media, motion parameters of cylinder and structure parameters of tumbling mill is studied based on discrete element method. The discrete element model of the traditional tumbling mill is established by programming using PFC3D software. The correctness of the discrete element model is verified by comparing the numerical simulation results with the theoretical calculation results of the grinding ball movement in ball mill getting by changing the structural parameters of the ball mill. The structure of traditional ball mill is improved in order to improve the production efficiency of tumbling mill. And the impact speed of the grinding media increases by adding a rotating baffle in the tumbling mill. The optimum parameters and the reasonable structure parameters of cylinder and rotating baffle are determined by studying the influence of the motion parameters and structure parameters on the grinding ball movement based on the discrete element method. The impact velocity of grinding ball increases from 2m/s to 5m/s getting from the simulation tests on the improved and former tumbling mills, the effect of impact and grinding of grinding balls on the particles are effectively enhanced. The maximum diameter of the particles which processed by the tumbling mill is increased. The limitation of drum diameter to improve the grinding efficiency is eased. Finally, the physical model of the tumbling mill is established. The modal analysis on the cylinder of the improved tumbling mill is made. And find that the cylinder will not resonate with external excitation. And the strength of the cylinder of improved tumbling mill meets the requirement by the stress finite element analysis.