GUEST BLOG by Dr Daniel Grasser, Consulting Engineer at TUNRA Bulk Solids, Australia.
Daniel’s expertise in solving industry problems using DEM relates to bulk materials handling including particle flow and design and optimisation of wear liners. This work was conducted during his affiliation with the ARC Training Centre in Alloy Innovation for Mining Efficiency (mineAlloy) at Deakin University, Australia, and in collaboration with Prof Matthew Barnett, A/Prof Michael Pereira and Dr Santiago Corujeira Gallo.
Fighting wear in bulk materials handling
Efficient mining of minerals is more important than ever. This includes the effective handling and transportation of large quantities of minerals. These minerals are often hard particles with sharp edges, which cause significant wear on the mining equipment, for example, the wear liners of chutes. This wear can lead to economic losses and environmental harm because resources are wasted and emissions generated when the worn liners are being replaced; hence, increasing the wear resistance of liners is important.
Reducing the need for experimental wear tests
To achieve maximum wear resistance, composites often combine the beneficial properties of at least two different materials. Composites can be utilised as wear liners and designed to reduce abrasive wear, however traditionally, extensive laboratory scale and field tests were needed. These experimental trials and field tests are expensive and difficult to perform. To reduce the need for experimental trials, Ansys/Rocky was used to simulate and predict the wear performance of composites. Targeted application for these composites were wear liners for mining applications, such as chutes.
Wear process of a composite caused by non-spherical particles studied with DEM.
For example, to reduce the costs of experimental trials, the Dry Sand Rubber Wheel (DRSW) wear test (a commonly used laboratory-scale abrasive wear test) was implemented in Ansys/Rocky DEM [1]. As a validation of the DEM implementation, the results of the DEM implementation showed good agreement with an initial set of experimental trials. From this, DEM was used to systematically study the wear performance of a wide range of proposed composite designs. As a result, composites wear liners with maximum wear resistance were developed, based on the understanding of the occurring flow regimes.
Figure 2: Implementation of a laboratory-scale wear test in DEM. Left image: DEM with position of the video indicated, right image: experiment.
Understanding the mineral particles’ flow mechanisms
Wear can be understood as the volume loss of a material (wear liner) caused by the interaction with another material (mineral particle). Wear is the result of this complex interaction. To reduce wear, physical quantities such as the velocity of the mineral particles, their sliding distance and the contact pressure need to be understood. To develop a composite with maximum wear resistance, these quantities need to be measured and systematically compared for different composite designs [1]. This is important in order to increase the service life, and therefore efficiency, of a wear liner for mining applications.
The composite design for bulk materials handling depends on several geometrical parameters, such as the size and spacing between the reinforcing inserts, in respect to the size of the mineral particles handled. These geometrical relationships determine the mineral particles’ flow and the resulting wear. To make meaningful conclusions, insights into the particles’ motion, such as sliding and rolling motions, must be understood. Ansys/ Rocky DEM allowed measuring these quantities because it is difficult to accurately assess these parameters experimentally.
Figure 3: Left image: wear of a composite, right image: analysis of the particle flow trajectories, both quantities were studied with DEM (laboratory-scale wear test).
The abrasive particle size distribution was simulated quantitatively (scale 1:1), and the particle shape (non-spherical) was implemented qualitatively, in the DSRW wear test.
Figure 4: Left image: implementation of non-spherical particles in DEM, right image: particle used in the experiments (laboratory-scale wear test).
Design principles for wear liners with maximum wear resistance
Based on these insights, an industry-scale chute was simulated in ANSYS/ Rocky DEM. Important quantities associated with the mineral particles’ flow, such as the particle flow trajectories indicating the particle velocity, were compared for different composite designs. For example, design principles leading to the formation of a protective particle layer, reducing abrasion and impacts, were discovered. Ultimately, the relationship between the size of the handled mineral particles, the design of the composite and the resulting wear were found. Based on these relationships, design principles for an optimum design were formulated [2].
Figure 5: Analysis of a chute. Left image: 3D view of a chute with a composite wear liner, centre image: conventional wear liner with the particle velocity indicated, right image: composite wear liner with an optimum design forming a slow-moving protective layer.
Conclusion
Using Ansys/ Rocky DEM, the need for experimental wear tests was reduced. Once a validated DEM setup was established, concepts and proposed design principles were tested more quickly than with experiments. Moreover, DEM allowed insight into the underlying particle flow mechanisms. Design principles for wear-resistant composites with inserts were formulated. Experimental trials on a laboratory scale indicated benefits of up to 43% in wear reduction [3], while even higher benefits are predicted for an industry scale chute [2]. This is an important step towards increased efficiency during bulk materials handling and related sectors in the mining industry.
Figure 6: Wear intensity. Left image: conventional wear liner, right image: composite wear liner with an optimum design.
About the author
Dr Daniel Grasser is interested in solving problems associated with bulk materials handling, such particle flow and wear of wear liners. Daniel’s expertise is numerical investigations using Discrete Element Modelling (DEM), experimental analysis of particle flow and resulting wear, and design engineering. The work presented in this study was conducted during the affiliation with the ARC Training Centre in Alloy Innovation for Mining Efficiency (mineAlloy) at Deakin University, Australia, and in collaboration with Prof Matthew Barnett, A/Prof Michael Pereira and Dr Santiago Corujeira Gallo. Currently, Daniel is a Consulting Engineer at TUNRA Bulk Solids, Australia, and solving industry problems related to bulk materials handling, especially for clients in the mining sector. We thank Daniel for sharing his research and engineering expertise with ANSYS/ Rocky DEM.
Contact
Dr Daniel Grasser
Daniel.Grasser@newcastle.edu.au
TUNRA Bulk
70 Vale Street
Shortland, NSW 2307, Australia
References
[1] Wear simulation and validation of composites (insert-reinforced matrix) in the dry sand rubber wheel test, Minerals Engineering, 2024, https://doi.org/10.1016/j.mineng.2024.108583
[2] Design principles for wear liners with inserts in mining chutes, Powder Technology, 2024, https://doi.org/10.1016/j.powtec.2024.119450
[3] Experimental investigation of the effect of insert spacing on abrasion wear resistance of a composite, Wear, 2022, https://doi.org/10.1016/j.wear.2022.204277
