球磨过程中介质群运动区域划分方法研究

球磨过程中介质群运动状态变化对物料的破碎效率影响极大,通过对介质群运动状态进行区域划分,探究不同球磨工况下的介质群运动区域特征更能有效揭示介质群对物料的破碎方式和有效破碎区域。针对理论划分介质群运动区域过于理想、单一,试验追踪法成本过高的问题,提出了一种介质群运动区域划分的新方法—EDEM网格划分法。首先把筒体的横截面划分为若干个微元,利用数理统计的方法得到介质群位置概率分布函数,获取介质群运动速度区域分布图和碰撞特性区域分布图。然后给出了回转运动、螺旋运动及复合颤振运动三种工况下介质群运动区域的划分实例,并与试验追踪法对比,验证了EDEM网格划分法的准确性和有效性。最后通过粉磨试验中进料的破碎速率和微细颗粒产率探讨了介质群运动区域特性对颗粒的破碎方式和有效破碎区域的影响效果。本研究为优化球磨过程的影响因素和操作参数提供了一种快捷、有效的方法。

Study on the Method of Dividing Media Motion Region in Ball Milling

The motion morphology of grinding media has an important effect on particles breakage efficiency in ball milling. In order to reveal the broken way and effective broken region when the motion morphology changes in different milling conditions, research on the regional division of the motion morphology of grinding media has been conducted. The theoretical dividing method is too ideal and less application, while the experimental tracking method costs too much time and money. Therefore, a new method of dividing the media motion morphology regions using EDEM grid partition has been proposed. The location function for each grid which is divided from the cross-section of the mill is obtained by the numerical statistics, combined with the regional distributions of media velocity vectors and collision characteristics, the regional distribution examples in three different milling condition, including rotational motion, spiral motion and coupled flutter motion have been provided. The comparison result with the experimental tracking method has verified the validity and availability of the EDEM grid partition method. In the end, the grinding test has been conducted, and the particles' broken way and effective broken region imposed by the media motion morphology has been discussed according to the particles broken effect and broken rate. This conclusion provides a fast and effective method to study and optimize the region changes in different influence factors.