Minerals

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20 pages, 12985 KiB

Open AccessEditor’s ChoiceArticle

Industry Scale Optimization: Hammer Crusher and DEM Simulations

by Błażej Doroszuk and Robert Król

Minerals 2022, 12(2), 244; https://doi.org/10.3390/min12020244 - 14 Feb 2022

Cited by 7 | Viewed by 4644

The paper shows the preparation of the numerical models necessary for the simulation mapping of industrial-scale crushers of problematic material, such as copper ore with complex lithology. The crushers investigated in this work are located in the KGHM Polska Miedz S.A. copper ore [...] Read more.

The paper shows the preparation of the numerical models necessary for the simulation mapping of industrial-scale crushers of problematic material, such as copper ore with complex lithology. The crushers investigated in this work are located in the KGHM Polska Miedz S.A. copper ore processing plant. The complex ore consisting of sandstone, dolomite and shale is modeled using the Discrete Element Method (DEM) with Particle Replacement Model (PRM) that was chosen to simulate the crushing process. The article discusses the tests and calibration of material parameters and proceeds to test a breakage model in a laboratory-scale jaw crusher. The results are finally validated with the data from actual industrial-scale crushers and compared with the simulations. As an optimization option, the new shape of hammers is proposed and tested in a numerical environment. The performance of the newly designed hammers was examined using numerical methods. The numerical tests showed that the new design performed worse than the current solution. As a result, time and money were saved by avoiding industrial tests. In conclusion, the work shows how complex processes can be characterized in the numerical environment and used for further analysis. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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26 pages, 10999 KiB

Open AccessArticle

Textural and Mineralogical Controls on Rock Strength Elucidated Using a Discrete Element Method Numerical Laboratory

by Temitope Oladele, Lawrence Bbosa and Dion Weatherley

Minerals 2021, 11(9), 1015; https://doi.org/10.3390/min11091015 - 18 Sep 2021

Cited by 5 | Viewed by 2285

Abstract

Numerical modelling techniques such as the discrete element method are now well established and extensively used in many applications including solid earth geoscience, materials science, geotechnical engineering and rock mechanics. The potential for this technique in understanding comminution mechanisms has been identified as [...] Read more.

Numerical modelling techniques such as the discrete element method are now well established and extensively used in many applications including solid earth geoscience, materials science, geotechnical engineering and rock mechanics. The potential for this technique in understanding comminution mechanisms has been identified as highly promising. This work utilizes the discrete element method as a numerical laboratory to conduct investigations relevant to comminution that would otherwise be costly or time-consuming to perform in the field or laboratory. A benchmark numerical model for impact breakage of rock specimens is first established and validated against results of controlled laboratory experiments. Thereafter, the model is utilized to systematically investigate the potential dependency of ore breakage properties upon the prevalence of pre-existing fractures, as well as the mineralogical composition of the ore. These numerical experiments serve to highlight the potential for quantitatively relating the mechanical response of ore to its textural and mineralogical characteristics. Tandem utilization of numerical and laboratory experimentation to formulate and test hypotheses is a promising avenue to illuminate such relationships. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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17 pages, 5606 KiB

Open AccessFeature PaperArticle

Use of Discrete Element Modelling to Evaluate the Parameters of the Sampling Theory in the Feed Grade Sampler of a Sulphide Gold Plant

by Marcus Félix Magalhães, Ana Carolina Chieregati, Dusan Ilic, Rodrigo Magalhães de Carvalho, Mariana Gazire Lemos and Homero Delboni

Minerals 2021, 11(9), 978; https://doi.org/10.3390/min11090978 - 8 Sep 2021

Cited by 3 | Viewed by 2477

Abstract

Cross-stream cutters are widely used in the mining and resources industry to obtain representative samples of particulate flows. Discrete element modelling (DEM) and analysis can be used to investigate influences of operational parameters, sampler design and material physical properties in the generation of [...] Read more.

Cross-stream cutters are widely used in the mining and resources industry to obtain representative samples of particulate flows. Discrete element modelling (DEM) and analysis can be used to investigate influences of operational parameters, sampler design and material physical properties in the generation of the Increment Extraction Error (IEE), which when present, results in a frequently biased, non-representative sample. The study investigates the practicality of the rules and recommendations proposed by Dr. Pierre Gy that were developed and established as principles for the correct extraction of samples in industrial sampling equipment. Results validate Pierre Gy’s sampling theory using DEM in a cross-stream cutter of a sulphide gold plant. Importantly, the outcomes indicate that careful consideration must be given to physical ore properties and, consequently, that sampling systems should be developed specifically to each application. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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30 pages, 8557 KiB

Open AccessArticle

Torque Analysis of a Gyratory Crusher with the Discrete Element Method

by Manuel Moncada, Patricio Toledo, Fernando Betancourt and Cristian G. Rodríguez

Minerals 2021, 11(8), 878; https://doi.org/10.3390/min11080878 - 13 Aug 2021

Cited by 14 | Viewed by 8418

Abstract

Comminution by gyratory crusher is the first stage in the size reduction operation in mineral processing. In the copper industry, these machines are widely utilized, and their reliability has become a relevant aspect. To optimize the design and to improve the availability of [...] Read more.

Comminution by gyratory crusher is the first stage in the size reduction operation in mineral processing. In the copper industry, these machines are widely utilized, and their reliability has become a relevant aspect. To optimize the design and to improve the availability of gyratory crushers, it is necessary to calculate their power and torque accurately. The discrete element method (DEM) has been commonly used in several mining applications and is a powerful tool to predict the necessary power required in the operation of mining machines. In this paper, a DEM model was applied to a copper mining gyratory crusher to perform a comprehensive analysis of the loads in the mantle, the crushing torque, and crushing power. A novel polar representation of the radial forces is proposed that may help designers, engineers, and operators to recognize the distribution of force loads on the mantle in an easier and intuitive way. Simulations with different operational conditions are presented and validated through a comparison with nominal data. A calculation procedure for the crushing power of crushers is presented, and recommendations for the selection of the minimum resolved particle size are given. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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21 pages, 7736 KiB

Open AccessArticle

Introducing Metamodel-Based Global Calibration of Material-Specific Simulation Parameters for Discrete Element Method

by Christian Richter and Frank Will

Minerals 2021, 11(8), 848; https://doi.org/10.3390/min11080848 - 6 Aug 2021

Cited by 8 | Viewed by 3156

Abstract

An important prerequisite for the generation of realistic material behavior with the Discrete Element Method (DEM) is the correct determination of the material-specific simulation parameters. Usually, this is done in a process called calibration. One main disadvantage of classical calibration is the fact [...] Read more.

An important prerequisite for the generation of realistic material behavior with the Discrete Element Method (DEM) is the correct determination of the material-specific simulation parameters. Usually, this is done in a process called calibration. One main disadvantage of classical calibration is the fact that it is a non-learning approach. This means the knowledge about the functional relationship between parameters and simulation responses does not evolve over time, and the number of necessary simulations per calibration sequence respectively per investigated material stays the same. To overcome these shortcomings, a new method called Metamodel-based Global Calibration (MBGC) is introduced. Instead of performing expensive simulation runs taking several minutes to hours of time, MBGC uses a metamodel which can be computed in fractions of a second to search for an optimal parameter set. The metamodel was trained with data from several hundred simulation runs and is able to predict simulation responses in dependence of a given parameter set with very high accuracy. To ensure usability for the calibration of a wide variety of bulk materials, the variance of particle size distributions (PSD) is included in the metamodel via parametric PSD-functions, whose parameters serve as additional input values for the metamodel. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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21 pages, 7628 KiB

Open AccessEditor’s ChoiceArticle

Investigation of Lateral Confinement, Roller Aspect Ratio and Wear Condition on HPGR Performance Using DEM-MBD-PRM Simulations

by Victor Alfonso Rodriguez, Gabriel K. P. Barrios, Gilvandro Bueno and Luís Marcelo Tavares

Minerals 2021, 11(8), 801; https://doi.org/10.3390/min11080801 - 23 Jul 2021

Cited by 24 | Viewed by 3469

Abstract

It has been known that the performance of high-pressure grinding rolls (HPGR) varies as a function of the method used to laterally confine the rolls, their diameter/length (aspect) ratio as well as their condition, if new or worn. However, quantifying these effects through [...] Read more.

It has been known that the performance of high-pressure grinding rolls (HPGR) varies as a function of the method used to laterally confine the rolls, their diameter/length (aspect) ratio as well as their condition, if new or worn. However, quantifying these effects through direct experimentation in machines with reasonably large dimensions is not straightforward, given the challenge, among others, of guaranteeing that the feed material remains unchanged. The present work couples the discrete element method (DEM) to multibody dynamics (MBD) and a novel particle replacement model (PRM) to simulate the performance of a pilot-scale HPGR grinding pellet feed. It shows that rotating side plates, in particular when fitted with studs, will result in more uniform forces along the bed, which also translates in a more constant product size along the rolls as well as higher throughput. It also shows that the edge effect is not affected by roll length, leading to substantially larger proportional edge regions for high-aspect ratio rolls. On the other hand, the product from the center region of such rolls was found to be finer when pressed at identical specific forces. Finally, rolls were found to have higher throughput, but generate a coarser product when worn following the commonly observed trapezoidal profile. The approach often used in industry to compensate for roller wear is to increase the specific force and roll speed. It has been demonstrated to be effective in maintaining product fineness and throughput, as long as the minimum safety gap is not reached. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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26 pages, 14610 KiB

Open AccessArticle

Full-Scale Simulation and Validation of Wear for a Mining Rope Shovel Bucket

by Andreas Svanberg, Simon Larsson, Rikard Mäki and Pär Jonsén

Minerals 2021, 11(6), 623; https://doi.org/10.3390/min11060623 - 11 Jun 2021

Cited by 12 | Viewed by 3637

Abstract

Failure in industrial processes is often related to wear and can cause significant problems. It is estimated that approximately 1–4% of the gross national product for an industrialized nation is related to abrasive wear. This work aims to numerically predict development of wear [...] Read more.

Failure in industrial processes is often related to wear and can cause significant problems. It is estimated that approximately 1–4% of the gross national product for an industrialized nation is related to abrasive wear. This work aims to numerically predict development of wear for full-scale mining applications in harsh sub-arctic conditions. The purpose is to increase the understanding of wear development in industrial processes and optimize service life and minimize costs related to wear. In the present paper, a granular material model consisting of the discrete element method (DEM) and rigid finite element particles is utilized to study wear in full-scale mining applications where granular materials and steel structures are present. A wear model with the basis in Finnie’s wear model is developed to calculate wear from combined abrasive sliding and impact wear. Novel in situ full-scale experiments are presented for calibration of the wear model. A simulation model of the rope shovel loading process is set up where the bucket filling process is simulated several times, and the wear is calculated with the calibrated wear model. From the full-scale validation, it is shown that the simulated wear is in excellent agreement when compared to the experiments, both regarding wear locations and magnitudes. After validation, the model is utilized to study if wear can be minimized by making small changes to the bucket. One major conclusion from the work is that the presented wear simulator is a suitable tool that can be used for product development and optimization of the loading process. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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16 pages, 6863 KiB

Open AccessFeature PaperArticle

Digital Twins with Distributed Particle Simulation for Mine-to-Mill Material Tracking

by Martin Servin, Folke Vesterlund and Erik Wallin

Minerals 2021, 11(5), 524; https://doi.org/10.3390/min11050524 - 15 May 2021

Cited by 9 | Viewed by 4471

Abstract

Systems for transport and processing of granular media are challenging to analyse, operate and optimise. In the mining and mineral processing industries, these systems are chains of processes with a complex interplay among the equipment, control and processed material. The material properties have [...] Read more.

Systems for transport and processing of granular media are challenging to analyse, operate and optimise. In the mining and mineral processing industries, these systems are chains of processes with a complex interplay among the equipment, control and processed material. The material properties have natural variations that are usually only known at certain locations. Therefore, we explored a material-oriented approach to digital twins with a particle representation of the granular media. In digital form, the material is treated as pseudo-particles, each representing a large collection of real particles of various sizes, shapes and mineral properties. Movements and changes in the state of the material are determined by the combined data from control systems, sensors, vehicle telematics and simulation models at locations where no real sensors could see. The particle-based representation enables material tracking along the chain of processes. Each digital particle can act as a carrier of observational data generated by the equipment as it interacts with the real material. This make it possible to better learn the material properties from process observations and to predict the effect on downstream processes. We tested the technique on a mining simulator and demonstrated the analysis that can be performed using data from cross-system material tracking. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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19 pages, 14029 KiB

Open AccessFeature PaperArticle

Grain-Based DEM for Particle Bed Comminution

by Michael Klichowicz and Holger Lieberwirth

Minerals 2021, 11(3), 306; https://doi.org/10.3390/min11030306 - 16 Mar 2021

Cited by 2 | Viewed by 3297

Abstract

The comminution at the grain size level for liberating the valuable minerals usually requires the highest size-specific energy. Therefore, a full understanding of the comminution process at this level is essential. Models based on the Discrete Element Method (DEM) can become a helpful [...] Read more.

The comminution at the grain size level for liberating the valuable minerals usually requires the highest size-specific energy. Therefore, a full understanding of the comminution process at this level is essential. Models based on the Discrete Element Method (DEM) can become a helpful tool for this purpose. One major concern, however, is the missing representativeness of mineral microstructures in the simulations. In this study, a method to overcome this limitation is presented. The authors show how a realistic microstructure can be implemented into a particle bed comminution simulation using grain-based models in DEM (GBM-DEM). The improved algorithm-based modeling approach is exemplarily compared to an equivalent real experiment. The simulated results obtained within the presented study show that it is possible to reproduce the interfacial breakage observed in real experiments at the grain size level. This is of particular interest as the aim of comminution in mineral processing is not only the size reduction of coarse particles, but often an efficient liberation of valuable components. Simulations with automatically generated real mineral microstructures will help to further improve the efficiency of ore processing. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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20 pages, 5244 KiB

Open AccessFeature PaperArticle

Grinding Media Motion and Collisions in Different Zones of Stirred Media Mills

by Greta Fragnière, Aleksandra Naumann, Marcel Schrader, Arno Kwade and Carsten Schilde

Minerals 2021, 11(2), 185; https://doi.org/10.3390/min11020185 - 11 Feb 2021

Cited by 12 | Viewed by 5850

Abstract

Product fineness during grinding in stirred media mills is mainly influenced by the specific energy input, the stress energy transferred by the colliding grinding media and the stress frequency. The stress energy from grinding media collisions is heterogeneously distributed in stirred media mills. [...] Read more.

Product fineness during grinding in stirred media mills is mainly influenced by the specific energy input, the stress energy transferred by the colliding grinding media and the stress frequency. The stress energy from grinding media collisions is heterogeneously distributed in stirred media mills. Herein, in order to characterize the stress energy distribution and the local grinding media collision frequencies, the grinding media motion was calculated using discrete element method (DEM) simulations coupled with computational fluid dynamics (CFD). The local grinding media concentration, velocity profiles, grinding media collisions and stress energies were compared for varied total grinding media fillings and stirrer speeds. It was confirmed that the normalized grinding media velocity profile can be used to divide the grinding chamber into four types of zones that allow the modeling of the stress energy distribution. However, the collision frequency showed very different distributions for varied stirrer velocities and grinding media fillings. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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19 pages, 9747 KiB

Open AccessEditor’s ChoiceArticle

A Novel Particle-Based Approach for Modeling a Wet Vertical Stirred Media Mill

by Simon Larsson, Juan Manuel Rodríguez Prieto, Hannu Heiskari and Pär Jonsén

Minerals 2021, 11(1), 55; https://doi.org/10.3390/min11010055 - 9 Jan 2021

Cited by 16 | Viewed by 3244

Abstract

Modeling of wet stirred media mill processes is challenging since it requires the simultaneous modeling of the complex multiphysics in the interactions between grinding media, the moving internal agitator elements, and the grinding fluid. In the present study, a multiphysics model of an [...] Read more.

Modeling of wet stirred media mill processes is challenging since it requires the simultaneous modeling of the complex multiphysics in the interactions between grinding media, the moving internal agitator elements, and the grinding fluid. In the present study, a multiphysics model of an HIG5 pilot vertical stirred media mill with a nominal power of 7.5 kW is developed. The model is based on a particle-based coupled solver approach, where the grinding fluid is modeled with the particle finite element method (PFEM), the grinding media are modeled with the discrete element method (DEM), and the mill structure is modeled with the finite element method (FEM). The interactions between the different constituents are treated by loose (or weak) two-way couplings between the PFEM, DEM, and FEM models. Both water and a mineral slurry are used as grinding fluids, and they are modeled as Newtonian and non-Newtonian fluids, respectively. In the present work, a novel approach for transferring forces between grinding fluid and grinding media based on the Reynolds number is implemented. This force transfer is realized by specifying the drag coefficient as a function of the Reynolds number. The stirred media mill model is used to predict the mill power consumption, dynamics of both grinding fluid and grinding media, interparticle contacts of the grinding media, and the wear development on the mill structure. The numerical results obtained within the present study show good agreement with experimental measurements. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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12 pages, 6959 KiB

Open AccessArticle

Exploring the End-Liner Forces Using DEM Software

by Ngonidzashe Chimwani and Murray M. Bwalya

Minerals 2020, 10(12), 1047; https://doi.org/10.3390/min10121047 - 24 Nov 2020

Cited by 5 | Viewed by 2287

Abstract

The main roles of liners are to protect the mill shell and promote effective ball motion for grinding. For this reason the liner profile is carefully selected to ensure that the productivity is maximized and due liner replacement is made when this objective [...] Read more.

The main roles of liners are to protect the mill shell and promote effective ball motion for grinding. For this reason the liner profile is carefully selected to ensure that the productivity is maximized and due liner replacement is made when this objective is no longer met. These issues have been extensively studied on shell liners as mill relining is a significant cost component of ball milling. To date, not much has been written about end-liners and the kind of forces they are subjected to. A discrete element method (DEM) simulation scheme is conducted to look at how ball size distribution, mill filling, end-liner configuration and shape affect the distribution of forces acting on the liners that were assessed to understand end-liner wear and damage. The results showed how forces varied both radially and tangentially for the different sections of end-liner, with important insights drawn for end-liner manufactures. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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23 pages, 7117 KiB

Open AccessArticle

A Dynamic Model of Inertia Cone Crusher Using the Discrete Element Method and Multi-Body Dynamics Coupling

by Jiayuan Cheng, Tingzhi Ren, Zilong Zhang, Dawei Liu and Xin Jin

Minerals 2020, 10(10), 862; https://doi.org/10.3390/min10100862 - 29 Sep 2020

Cited by 11 | Viewed by 4768

Abstract

The cone crusher is an indispensable equipment in complex ore mineral processing and a variant of the cone crusher is the inertia cone crusher. A real-time dynamic model based on the multibody dynamic and discrete element method is established to analyze the performance [...] Read more.

The cone crusher is an indispensable equipment in complex ore mineral processing and a variant of the cone crusher is the inertia cone crusher. A real-time dynamic model based on the multibody dynamic and discrete element method is established to analyze the performance of the inertia cone crusher. This model considers an accurate description of the mechanical motions, the nonlinear contact, and the ore material loading response. Especially the calibration of ore material simulated parameters is based on the Taguchi method for the Design of Experiments. For model verification, the industrial-scale experiment was conducted on a GYP1200 inertia cone crusher. Two different drive speeds were included in the experiments, and the testing devices were used to acquire crusher performances, for instance, displacement amplitude, power draw, product size distribution, and throughput capacity in order to accurately compare simulation results. The preliminary model can be qualitatively evaluated the flow pattern of particles and quantitatively evaluated the crushing force distribution in the concave. Furthermore, the simulation predicts the variety of crusher performances using the drive speed and the fixed cone mass as input variables. The simulation model provides novel insight regarding the improvement of linings wear period, lowering manufacturing cost, and obtaining optimal operation parameters. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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