Simulation of solids flow and energy transfer in a vertical shaft impact crusher using DEM

In spite of its relative operational simplicity and earlier attempts to model its performance, the Vertical shaft impact (VSI) crusher is still lacking a comprehensive mathematical description that allows predicting its performance accurately. One of the reasons is the limited knowledge of particle interaction and solids flow inside the machine. The paper deals with the application of the discrete element method (DEM) in the prediction of solids flow within a pilot-scale VSI crusher operating under different conditions. A large amount of data has been generated and used to calculate the collision energy spectra, as well as the residence time distributions of rock particles that are fed to the machine. It is shown that the collision energy distribution and frequency change significantly if rock or a ring of steel anvils is used as the target and also if a cascading flow of material bypasses the rotor directly into the crushing chamber. Finally, it is discussed how these data, along with models that describe breakage and damage of single particles, can serve as the basis for the development of a fully-predictive model of comminution in this machine in the future.

Figure optionsDownload as PowerPoint slideHighlights
► Breakage energies and frequencies in a VSI can be predicted using DEM.
► The presence or absence of rocks covering anvils influence VSI simulations.
► Residence times are longer for cascading than for ejected rocks.
► Residence times are longer for ejected rocks with autogenous rock beds as anvils.
► DEM can provide valuable data for simulating breakage in VSI using PBM.