Research On Working Parameters Optimization Of Ball Mill Using Discrete Element Method

Ball mill is one of the main equipments on mineral processing for particle size reduction, it is widely used because of its advantages such as high throughput, easy operation, compact structure and so on. However, it has several prominent defects such as high power consumption and low efficiency. Accordingly, it is meaningful to improve grinding efficiency and reduce energy consumption. In industry production, unreasonable work parameter value is one major reason for high energy consumption and low efficiency of ball mill. To solve this problem, the influencing mechanism of working parameters on mill performance must be analysed, ore broken mechanism in ball mill will be studied using discrete element method. The reasonable work parameter values will be obtained by numerical simulation experiment so as to improve mill performance.The research object of the thesis is Φ2100mm×3000mm industrial ball mill in a dressing plant. Experiment program was drafted by uniformly orthogonal design method. Based on discrete element method, in ball mill grinding test was numerically simulated using three-dimensional discrete element software EDEM. Experimental indicators were a few main mill performance indicators—throughput, grinding efficiency, useless energy consumption, operational stability, which reflect the mill performance from different aspects. Three remarkable factors—rotational speed rate, fill rate, powder-to-ball weight ratio which impact the work status of ball mill were selected as experimental factors.Research found that the main impact breakage way of ore grains is mostly incremental impact breakage by multiple effective low energy impact events. Combing the experimental data such as impact energy, instantaneous torque and the related mathematical model such as breakage probability model, mill performance parameter values are worked out. Experimental results are analysed by regression analysis method, then the regression model between each index and working parameters are set up, combination value of reasonable working parameters is find out. Compared with the actual operation, after parameters optimization, throughput is increased significantly, specific energy consumption is greatly declined, useless energy consumption is reduced, operational stability is improved. In addition, the product particle size distribution is predicted using breakage severity model.