Optimization Of Semi-self-grinding Media In Wushan Copper Mine Based On Discrete Element Method

Due to the advantages of short process flow,low operation cost and high production capacity,semi-autogenous mill is widely used in the mining industry.For a long time,many scholars and technicians on mineral processing have studied the grinding mechanism and formed a lot of grinding theory starting from the motion state of grinding medium and ore in semi-autogenous mill.Because of the complexity of grinding system,grinding mechanism of semi-autogenous mill is still ununderstood.Based on the research project about optimization study of semi-autogenous mill grinding medium and domestic and foreign reference on the study of s semi-autogenous mill grinding mechanism,this paper launches the optimization study on semi-autogenous mill grinding medium in wushan copper mine by discrete element method.Under the prerequisites of normal semi autogenous mill feed size distribution,75%speed ration and 35%filling rate,the discrete element simulation study was carried out with 180mm rod-ball,150mm steel ball and new-150mm-steel ball.Starting from the collision energy spectrum of grinding media and 20mm?150mm in semi-autogenous mill with ore broken theory,taking ore broken probability,production capacity,medium consumption as the evaluation criteria for semi autogenous grinding efficiency and combining with the laboratory verified tests,to provide a scientific basis for the research and optimization of the industrial test in wushan copper mine.Discrete element simulation research found that the steel ball plays an important role on ore broken,and +100mm ore used as grinding medium plays a supporting role,because impact energy between ball medium and ore is much higher than that of ore medium.According to the grinding effect of the three type grinding medium,the new 150mm steel ball performs best generally.When the new-150-mm steelball is adopted,ore broken probability is 0.6958%,and there is no broken behavior happened to+100mm ore;production capacity of semi-autogenous mill is 85.61t/h,which is 55.18t/h higher than the 1#semi-autogenous mill adopted 180mm rod-ball;relative value of grinding media consumption is 0.54,which is the lowest in the three type medium.Laboratory verified tests results,as same as the prediction of discrete element simulation basically,show that the new 150mm steel ball performs bests that fraction of +100mm ore used as grinding medium increases gradually,fraction of 35mm?50mm decreases,fraction of qualified grade and grinding ability is higher,fraction of over-grinding is lower.The industrial test results show that the new 150mm steel ball achieved a perfect results that grinding efficiency is increased from 119.8t/h to 129.23t/h,and 9.25t/h higher than before,i.e.8%increments;medium steel consumption decreased from 0.827kg/t to 0.555kg/t,and 0.272kg/t lower than before,i.e.a decline of 32.89%,the lowest in all media;+0.20mm fraction in the discharge from 53.01%to 51.7%,a decrease of 1.31 percentage points,the fraction of-0.074mm increased from 35.71%to 38.76%,an increase of 3.05 percentage points,the fraction of-0.038mm increased from 25.31%to 26.75%,an increase of 1.44 percentage points.The results of industrial experiments and laboratory verified tests are in full agreement with the simulation results,which verifies the reliability of the discrete element simulation.