Numerical Simulation of a Single and Double-Rotor Impact Crusher Using Discrete Element Method

Murray M. Bwalya,Ngonidzashe Chimwani

doi:10.3390/min12020143

Murray M. Bwalya, Ngonidzashe Chimwani

Open Access

https://doi.org/10.3390/min12020143

Copy DOI

Abstract

The Discrete element method (DEM) is an invaluable tool for studying comminution as it provides detailed information that can help with process analysis as well as trying out new equipment designs before the equipment is physically built. The DEM was used to analyse previous experimental work to gain some insight into the comminution process in an impact crusher with a single impeller. Further DEM simulations were done on a crusher with a second impeller installed. The energy spectra and threshold energy levels calculated from the drop-weight test were used as the basis of comparison. The simulations indicate that even at much lower speeds, the performance of a double impeller impact crusher is exceedingly superior. However, the energy associated with the double impeller impact crusher is much higher and energy intensification, rather than energy efficiency, is the main gain of the double impeller design. The double impeller also offers more operational flexibility, such as spacing between the impellers, which can be tailored to the particle size range being handled.

Highlights

Comminution is a size reduction step that precedes physical separation, as valuable mineral grains must be freed by breakage from the gangue host matrix in order for them to respond to the separation process
With the valuable insights drawn from the foundational work done on systematic particle-based modelling for a wide range of crushers [3,5], this study focuses on the design factors that can improve the performance of an impact crusher
Following promising results obtained in a single impeller crusher that involved repeated crushing of the product [17], the crusher design was improved by introducing a second impeller so that particles encounter two comminution stages before descending to the bottom of the device

Summary

Introduction

Comminution is a size reduction step that precedes physical separation, as valuable mineral grains must be freed by breakage from the gangue host matrix in order for them to respond to the separation process. The larger amount of energy applied to the comminution process does not contribute to particle breakage, but is rather wasted on processes such as driving the mechanical parts of the equipment, heat, and sound energy [1]. Comminution comprises crushing and grinding, but the former has been proven to be 10 to 20 times more energyefficient than the later [2]. Grinding has received more attention than crushing over the years, possibly missing out on possible gains which can be achieved by improving crushing [3]

Methods

Results

Conclusion