基于DEM的球磨机内介质碰撞特征研究

Study on Medium Collision Characteristics in Ball Mill Based on DEM

针对某铅锌矿选厂球磨机排矿粒度指标不理想,通过破碎统计力学进行介质配比优化,得到球磨机介质推荐补加方案Φ120 mm:Φ100 mm:Φ90 mm=50∶20∶30。使用Solidworks建立具有代表性的球磨机筒体,基于离散元方法,对现场及推荐介质配比进行仿真模拟研究。引入了惰性区面积作为评价磨矿介质方案合理的指标之一,将球磨机内惰性区域面积进行对比,得出优化后的推荐方案介质配比流动性较现场方案有一定提升,惰性区面积有所减小。将介质群运动状态、速度分布特征进行对比分析,中介质群循环中心坐标向右上方由(22.8,9.8)偏移到(24,12),表明推荐方案增加了磨机内的相对速度。通过引入不同尺寸矿石的断裂能以及数值模拟磨机内碰撞能量分析得出,大颗粒矿石的一次破碎次数基本为零,粗颗粒破碎是以研磨为主导的疲劳破碎,细颗粒破碎主要是冲击破碎。通过离散元方法模拟验证了推荐方案在各方面优于现场方案,提高了球磨机内的有效研磨面积,提高了能量的利用率,降低了能耗,证明了推荐方案优于现场方案,研究结果为选厂球磨机介质配比的优化提供了参考和指导。

Addressing the problem that at a lead-zinc ore processing plant the ball mill discharge size index is not ideal,the crushing statistical mechanics was used to optimize the size ratios of the grinding media,obtaining the ball mill media recommended replenishment schemeΦ120 mm:Φ100 mm:Φ90 mm=50∶20∶30.Using Solidworks to build a representative ball mill cylinder,based on the discrete element method,the field and the recommended media ratios were studied by simulation.The research introduced the inert area as one of the indicators for evaluating the reasonableness of the grinding media program,compared the inert area in the ball mill,and concluded that the optimized media ratio mobility of the recommended program has been improved compared with the on-site program,and the area of the inert area has been reduced.The media group movement state,velocity distribution characteristics,comparative analysis,the center of the media group circulation center coordinates to the upper right by(22.8,9.8)offset to(24,12),indicating that the recommended program increases the relative velocity in the mill.The analysis by introducing the fracture energy of different sizes of ores and numerical simulation of collision energy in the mill concluded that the number of primary crushing of large-grained ores is basically zero,coarse-grained crushing is fatigue crushing dominated by grinding,and fine-grained crushing is mainly impact crushing.The simulation by discrete element method verifies that the recommended scheme is better than the field scheme in all aspects,improves the effective grinding area in the ball mill,improves the utilization of energy,reduces energy consumption,proves that the recommended scheme is better than the field scheme,and the results of the study provide a reference and guidance for the optimization of the media ratios of the ball mill of the processing plant.