Discrete Element Simulation Analysis Of Influencing Factors Of Grinding Performance Of Ball Mill

Ball mill is an important and widely used grinding equipment,in the process of grinding operation,it is input a lot of energy to maintain moving steadily and continuously.The ball mill has a low grinding efficiency because a large part of its energy is wasted,so it is necessary to study the factors that influence the grinding effect of ball mill.In this paper,a discrete element software,EDEM,was used to simulate the industrial ball mill of(37)3.2m×4.5m specification.The effect of three kinds of liner shapes,including rectangle,trapezoidal and waveform,on grinding efficiency of ball mill was studied.The waveform liner was selected,and the influence of grinding parameters,that are rotation speed rate and filling rate,on grinding efficiency of ball mill was analyzed.The effect of ore particle shape on grinding efficiency of ball mill was studied under certain rotation speed rate and filling rate.The effects of liner shapes on grinding performance of ball mill were studied.The motion of particles,ball mill power,collision energy distribution of ore particles and stress distribution of cylinder were analyzed.The results show that the shape of liner has a great influence on the motion of particles in the ball mill,and the rotation speed rates of the ball mills with different shapes of liner are different when they achieve their best grinding effect respectively.With the increase of rotation rate,the power of ball mill with different liner shapes will increase,but the increase is different.The collision energy distributions of ore particles in ball mills with three kinds of liner shapes exist differences when they are at their respective appropriate rotation speed rates.With the increase of the rotation rate,the maximum stresses of ball cylinders with three kinds of liner shapes gradually increase.The effects of rotation speed rate and filling rate on grinding performance of ball mill were studied.The motion of particles,ball mill power,impact characteristic of grinding media,collision energy distribution of ore particles,stress distribution of cylinder and wear amount of liner were analyzed.The results show that the higher the rotation speed rate is,the higher the lifting height of the particles is,and the more particles are cast in the outermost layer,while the filling rate has opposite effects.When the speed exceeds the critical speed,the particles start to do centrifugal movement.When the rotation speed does not exceed the critical speed,the power increases with the increase of the rotation speed rate and filling rate,but the increase decreases.The number of collisions decreases when the rotation speed rate increases,while it increases when the filling rate increases.But when the filling rate is too high,the number of collisions in the effective collision energy range decreases.The larger the rotation speed rate and filling rate are,the greater the maximum stress of cylinder and wear amount of the liner of the ball mill will be.The effects of ore particle shapes on the grinding performance of ball mill were studied.The motion of particles,ball mill power,collision energy of ore particles,stress distribution of cylinder and wear amount of liner were analyzed.The results show that when the ore particle shape is spherical,ellipsoid and polyhedron respectively,the motion status of particles in ball mill is similar.When spherical ore particles are used,the power consumption is the minimum.The collision energy of ore particles is the maximum at the minimum collision times.when the ore particle shapes are spherical,the maximum stress of cylinder is the maximum,the wear amount of liner is the minimum.In this paper,the grinding performance of the ball mill is studied from the three aspects,that are mill structure,working condition parameters and material properties,in order to provide meaningful reference value for the ball mill to choose the right shape of liner,the appropriate working condition parameters and adopt the appropriate ore particle model to carry out simulations.