scholarly journals Grain-based DEM for Particle Bed Comminution

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 306
Author(s):  
Michael Klichowicz ◽  
Holger Lieberwirth
Keyword(s):  
Grain Size ◽  
Discrete Element Method ◽  
Specific Energy ◽  
Coarse Particles ◽  
Full Understanding ◽  
Real Experiment ◽  
Helpful Tool ◽  
Ore Processing ◽  
Comminution Process ◽  
Particle Bed

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.

scholarly journals Particle Size Effects on Selectivity in Confined Bed Comminution

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 342
Author(s):  
Holger Lieberwirth ◽  
Lisa Kühnel
Keyword(s):  
Particle Size ◽  
High Pressure ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Size Effects ◽  
Experimental Investigations ◽  
Ore Processing ◽  
Tumbling Mills ◽  
Particle Bed ◽  
Vertical Roller

Confined bed comminution in high-pressure grinding rollers (HPGRs) and vertical roller mills (VRMs) was previously used preferably for grinding comparably homogeneous materials such as coal or clinker. Meanwhile, it started to complement or even replace tumbling mills in ore beneficiation with ore and gangue particles of rather different breakage behaviors. The selectivity in the comminution of a mixture of particles with different strengths but similar particle size distribution (PSD) of the constituents in a particle bed was investigated earlier. The strength of a material is, however, also a function of particle size. Finer particles tend to be more competent than coarser ones of the same material. In industrial ore processing using confined bed comminution, this effect cannot be neglected but even be exploited to increase efficiency. This paper presents research results on this topic based on experimental investigations with model materials and with natural particles, which were stressed in a piston–die press. It appeared that the comminution result substantially depends on the material characteristics, the composition of the mixture and the PSD of the constituents. Conclusions will be drawn for the future applications of selective comminution in mineral processing.

Grinding Performance of Porous Diamond Wheels on Different Materials

2011 ◽  
Vol 189-193 ◽  
pp. 3191-3197
Author(s):  
Qiu Lian Dai ◽  
Can Bin Luo ◽  
Fang Yi You
Keyword(s):  
Grain Size ◽  
Specific Energy ◽  
Experimental Results ◽  
Grinding Process ◽  
High Porosity ◽  
Grinding Forces ◽  
Abrasive Grain ◽  
Grinding Conditions ◽  
Medium Porosity ◽  
The One

In this paper, metal-bonded diamond wheels of different sized abrasive grain with different porosity were fabricated. Grinding experiments with these wheels on three kinds of materials were carried out under different grinding conditions. Experimental results revealed that wheel with high porosity (38%) had smaller grinding forces and specific energy than the one with a medium porosity (24%) on grinding G603. However, on grinding harder materials like Red granite or ceramics of Al2O3, the wheel with 38% porosity had bigger grinding forces and specific energy than the wheel with 24% porosity. Both wheels exhibited good self-sharpening capability during the grinding process of G603 and Red granite, but on grinding ceramics of Al2O3 the wheel with 38% porosity displayed in dull state during the grinding process . With the same porosity, the grinding forces of the wheel with a grain size of 230/270 US mesh were lower than the one with a grain size of W10 when grinding Red granite and ceramics of Al2O3. However revising results were obtained on grinding G603.

Effects of Grain Size and Operating Parameters on the Mechanics of Grinding

1972 ◽  
Vol 94 (3) ◽  
pp. 833-842 ◽  
Author(s):  
S. Kannappan ◽  
S. Malkin
Keyword(s):  
Grain Size ◽  
Specific Energy ◽  
Energy Input ◽  
Unit Area ◽  
Grinding Wheel ◽  
Operating Parameters ◽  
Specific Cutting Energy ◽  
Cutting Energy ◽  
G Ratio ◽  
Table Speed

An investigation is described of the effects of grain size and operating parameters on the mechanics of grinding. Results indicate that the specific cutting energy in grinding, which is the total specific grinding energy minus the specific energy due to sliding between the wear flats and the workpiece, is independent of grain size and decreases with increasing table speed and downfeed. It is postulated that the specific cutting energy consists of chip forming energy which is independent of table speed and downfeed, and plowing energy which decreases with increasing table speed and downfeed. Results for G-ratio, surface finish, and burning conditions are also presented. Of particular interest are the effects of grain size on burning conditions. With finer grain size, burning occurs at larger wear flat area and energy input per unit area ground, but the G-ratio and grinding wheel tool life are less. This is related to increased attritious wear with finer grains.

scholarly journals A FRAMEWORK FOR COMMINUTION CIRCUITS DESIGN EVALUATION USING GREY COMPROMISE PROGRAMMING

2013 ◽  
Vol 14 (Supplement_1) ◽  
pp. S188-S212 ◽  
Author(s):  
Dragisa Stanujkic ◽  
Sanja Stojanovic ◽  
Rodoljub Jovanovic ◽  
Nedeljko Magdalinovic
Keyword(s):  
Decision Making ◽  
Circuit Design ◽  
Simple Procedure ◽  
Multiple Criteria Decision Making ◽  
Business Environment ◽  
Compromise Programming ◽  
Ore Processing ◽  
Comminution Process ◽  
Design Selection ◽  
Decision Making Model

Comminution process, particularly grinding, is very important in the mineral processing industry. Some characteristics of ore particles, which occur as a product of grinding process, have a significant impact on the effects of further ore processing. At the same time, this process requires a significant amount of energy and also significantly affects the overall processing costs. Therefore, in this paper, we propose new multiple criteria decision making model based on grey compromise programming for adequate comminution circuit design selection. Although it is based on a simple procedure, we consider that the proposed model is efficient and flexible, and that it also represents the basis for forming more sophisticated models for comminution circuit design selection, as in addition, many other decision making problems in business environment, which is characterized by predictions and uncertainty.

scholarly journals Effect of Annealing on Structure and Mechanical Behavior of an AA2139 Alloy

2014 ◽  
Vol 783-786 ◽  
pp. 258-263 ◽  
Author(s):  
Damir Tagirov ◽  
Daria Zhemchuzhnikova ◽  
Marat Gazizov ◽  
Rustam Kaibyshev
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Flow Stress ◽  
Room Temperature ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Aged Alloy ◽  
Coarse Particles ◽  
Initial Material ◽  
High Ductility

An AA2139 alloy with a chemical composition of Al–4.35Cu-0.46%Mg–0.63Ag-0.36Mn–0.12Ti (in wt.%) and an initial grain size of about 155 μm was subjected to annealing at 430°C for 3 h followed by furnace cooling. This treatment resulted in the formation of a dispersion of coarse particles having essentially plate-like shape. The over-aged alloy exhibits lower flow stress and high ductility in comparison with initial material in the temperature interval 20-450°C. Examination of microstructural evolution during high-temperature deformation showed localization of plastic flow in vicinity of coarse particles. Over-aging leads to transition from ductile-brittle fracture to ductile and very homogeneous ductile fracture at room temperature.

scholarly journals Ripples and grains segregation on unpaved road

2018 ◽  
Vol 29 (12) ◽  
pp. 1850120 ◽  
Author(s):  
Tiago Moy da Silva ◽  
Américo T. Bernardes
Keyword(s):  
Grain Size ◽  
Gravitational Field ◽  
Discrete Element Method ◽  
Computational Study ◽  
Discrete Element ◽  
Developed Countries ◽  
Unpaved Roads ◽  
Unpaved Road ◽  
Size Dispersion ◽  
Product Costs

Ripples or corrugations are common phenomena observed in unpaved roads in less developed countries or regions. They cause several damages in vehicles leading to increased maintenance and product costs. In this paper, we present a computational study about the so-called washboard roads. Also, we study grain segregation on unpaved roads. Our simulations have been performed by the Discrete Element Method (DEM). In our model, the grains are regarded as soft disks. The grains are subjected to a gravitational field and both translational and rotational movements are allowed. The results show that wheels’ of different sizes, weights and moving with different velocities can change corrugations amplitude and wavelength. Our results also show that some wavelength values are related to specific wheels’ speed intervals. Segregation has been studied in roads formed by three distinct grain diameters distribution. We observed that the phenomenon is more evident for higher grain size dispersion.

scholarly journals Grain Size Effect on the Mechanical Behavior of Cohesionless Coarse-Grained Soils with the Discrete Element Method

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Renjie Wen ◽  
Cai Tan ◽  
Yong Wu ◽  
Chen Wang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Shear Strength ◽  
Size Effect ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Force Chain ◽  
Coarse Grained ◽  
Biaxial Compression ◽  
Grain Sizes

Biaxial compression tests with the same specimen size and different maximum grain sizes were simulated for coarse-grained soils using the discrete element method to study the influence of grain size on the mechanical properties and force chain. The maximum grain sizes were 40, 20, 10, and 5 mm, respectively. The grading with self-similar fractal structure in mass is designed to ensure the same pore structure for soils. The shear strength increased with the increase in maximum grain size. Evident increase in shear strength and significant size effect were observed when the ratio of the specimen diameter to maximum grain size was less than five. The shear dilation of coarse-grained soils increases with the increase in maximum grain size. The contact force distribution was uniform when maximum grain size was small but tends to be uneven with the increase in maximum grain size, thereby causing the increase in shear strength by stable strong force chains. This finding demonstrates size effect on the mechanical properties and force chain of cohesionless coarse-grained soils under the biaxial compression condition.

scholarly journals Stress analysis of an agitated particle bed with different particle aspect ratios by the discrete element method

2017 ◽  
Vol 140 ◽  
pp. 06022
Author(s):  
Wei Pin Goh ◽  
Mojtaba Ghadiri ◽  
Frans Muller ◽  
Kushal Sinha ◽  
Nandkishor Nere ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Stress Analysis ◽  
Discrete Element ◽  
Aspect Ratios ◽  
Particle Bed ◽  
Element Method

Microstructure Control Using Precipitate Phases for the Development of Heat Resistant Fe3Al-based Alloys

2006 ◽  
Vol 980 ◽  
Author(s):  
Satoru Kobayashi ◽  
Stefan Zaefferer
Keyword(s):  
Grain Size ◽  
Carbide Phase ◽  
Fine Particle ◽  
Fine Particles ◽  
Composition Range ◽  
Particle Density ◽  
Coarse Particles ◽  
Thermomechanical Process ◽  
Fine Grained ◽  
Special Composition

AbstractA thermomechanical process (TMP) was performed to create a fine grained and recovered structure with densely formed fine particles in Fe3Al-Cr-Mo-C alloys. The TMP consists of two parts; the first part is to obtain fine recrystallised grains using coarse particles and the second to produce deformed/recovered structure using fine particles. It was found that k-Fe3AlC (E21) carbide phase tends to precipitate coarsely, which is effective to refine grain size in the first process. In a special composition range, the k carbide phase is thermo- dynamically stable in the Fe3Al matrix only at higher temperatures and fine M(Mo,Cr,Fe)2C (B81) carbide phase precipitates at lower temperatures. This fine M2C particles stabilize recovered structure by inhibiting the migration of subboundaries in the second process. This result suggests that if the fine particle density remains high, recovered structure can be maintained at 700°C.

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