Design Of SAG Mill Liner Based On Bond Theory And Discrete Element Method

SAG mill is a large-scale grinding equipment,and it's now used by more and more large-scale concentrators for its advantages,such as large body,high processing capacity,simple to process and easy to achieve in automation.But precisely because of its large size characteristics,the liner of mill often wear too fast,and which results in the need for frequent replacement and maintenance,so most SAG mills are not so good in efficiency.According to statistics,the operating rate for those who used SAG mill circuit system is less than 80%,while it's 95%for those who used traditional ball mill circuit.As SAG mill is used in many fields,it's vital to improve the SAG mill liner structure to improve the operating rate of the SAG mill.According to a large domestic copper mine survey,it's found that the processing capacity,energy consumption and product size of the three main performance index continued to improve when the liner is worn,and the worn cylinder liner is similar to the wave liner used in the ball mill.Based on the discrete element theory and the BPM theory in rock mechanics,this paper establishes the BPM bond model of ore.The model makes up for the defects of poor applicability of the broken probability model,in the meantime,this model solves the shortcomings of ignoring the ore crushing energy with the ore size changes in the critical ratio energy method.The method is used to analyze the collision energy and broken bond number.By coupling the EDEM and ANSYS to study the equivalent stress and its distribution of the liner,the method solves the problems of poor visual performance and complicated processing steps of the EDEM software.The wear amount of the liner was analyzed by using the Archard wear model,this method can be used to qualitative analyze the wear amount and wear area of the liner,which is of great value and engineering significance to study the wear principle of liner and improve the grinding performance and wear resistance of liner.By analyzing the number of broken bonds and the effective collision energy,it is found that the trapezoidal liner has a better ability in lifting the materials,and the wave liner has a better ability in breaking ores.The results of the static analysis show that the stress concentration happens at the corners and the transition position between the lifting bar and the base on the trapezoidal liner,and the stress distribution of the wave liner is uniform,and the stress of the wave liner is much smaller than the trapezoidal liner at the same position.According to the analysis results of the wear amount of the liner,it can be seen that the wear amount of the trapezoidal liner is smaller and the service life is longer.Based on the above research results,this paper argues that the trapezoidal liner should be designed into a split body,and the corners being smoothed;As for the design of the wave liner,both sides of the main lift should be added with auxiliary lift,and the size of auxiliary lift is 1/3 of the main lift.At the same time,in order to verify the correctness of this design method,the new liner and original liner are compared and analyzed,it is found that the new liner has a great improvement in both grinding effect and wear resistance.