Investigation of the effect of filling level on the wear and vibration of a SAG mill by DEM

Semi-autogenous grinding(SAG)mill is widely used in the grinding process of coal and ores because of its strong applicability,large capacity and low consumption of grinding media.Therefore,the research of SAG mill is still of great important practical significance.Among those parameters of the SAG mill,the flling level is very important for it is not only directly related to the processing capacity of the mill,but also affects the operation cost and stability of mill.In this paper,combined with shear impact energy model(SIEM)and discrete element method(DEM),the particle collision energy spectrum was applied to analyze the influence of ore flling level and media flling level on the power draw of the mill,the impact energy on ore,and the wear of liner and media in a slice of an industrial SAG mill.It was found that increasing the ore flling level would increase energy consumption and reduce the energy efficiency and the wear of liner and grinding media.Furthermore,the vibration of mill was explored from the collision energy on liner.The results showed that the low frequency but high energy ollision between grinding media and liner was the main reason for liner wear and mill vibration.

Reliability study of super-ellipsoid DEM in representing the packing structure of blast furnace

In industrial blast furnaces(BFs),the investigations involving the flow behaviors of particles and the resultant burden structure are essential to optimize its operation stability and energy consumption.With the advance of computing capability and mathematical model,the discrete element method(DEM)specialized in characterizing particle behavior has manifested its power in the investigation of BFs.In the framework of DEM,many particle models have been developed,but which model is more suitable for simulating the particle behaviors of BFs remains a question because real particles in BFs have large shape and size dispersity.Among these particle models,the super-ellipsoid model possesses the ability to change shape flexibly.Therefore,the focus of this study is to investigate whether the super-ellipsoid model can meet the requirement of authenticity and accuracy in simulating the behaviors of particles with large shape and size dispersity.To answer this question,a simplified BF charging system composed of a hopper and a storage bin is established.The charging process and the final packing structure are analyzed and compared between experiments and simulations with different shape indexes.The results show that super-ellipsoid particles have prominent advantages over spherical particles in terms of representing the real BF particles,and it can more reasonably reproduce the flow behaviors and packing structure of experimental particles.The computation cost of super-ellipsoid particles is also acceptable for engineering applications.Finally,the micro-scale characteristics of packing structure is analyzed and the single-ring charging process in industry-scale BF using super-ellipsoid particles is conducted.