Diese Forschung zielt darauf ab, den Einsatz realistischer Mineralmikrostrukturen in Mineralverarbeitungssimulationen Simulationen von Aufbereitungsprozessen zu ermöglichen. Insbesondere Zerkleinerungsprozesse, wie z.B. das Brechen und Mahlen von mineralischen Rohmaterialien, werden stark von der mineralischen Mikrostruktur beeinflusst, da die Textur und die Struktur der vielen Körner und ihre mikromechanischen Eigenschaften das makroskopische Bruchverhalten bestimmen.
Ein Beispiel: Stellen wir uns vor, wir haben ein mineralisches Material, das im Wesentlichen aus Körnern zweier verschiedener Mineralphasen, wie Quarz und Feldspat, besteht. Wenn die mikromechanischen Eigenschaften dieser beiden Phasen unterschiedlich sind, wird sich dies wahrscheinlich auf das makroskopische Bruchverhalten auswirken. Unter der Annahme, dass die Körner eines der Minerale bei geringeren Belastungen brechen, ist es wahrscheinlich, dass sich ein Riss durch einen Stein dieses Materials durch die schwächeren Körner ausbreitet. Tatsächlich ist dies eine wichtige Eigenschaft für die Erzaufbereitung. Um wertvolle Mineralien aus einem Erz zu gewinnen, ist es wichtig, sie aus dem kommerziell wertlosen Material, in dem sie vorkommen, zu befreien. Dazu ist es wichtig zu wissen und zu verstehen, wie das Material auf Korngrößenebene bricht.
Um diesen Bruch simulieren zu können, ist es wichtig, realistische Modelle der mineralischen Mikrostrukturen zu verwenden. Diese Studie zeigt, wie solche realistischen zweidimensionalen Mikrostrukturen auf der Grundlage der quantitativen Mikrostrukturanalyse am Computer erzeugt werden können. Darüber hinaus zeigt die Studie, wie diese synthetischen Mikrostrukturen dann in die gut etablierte Diskrete-Elemente-Methode integriert werden können, bei der der Bruch von mineralischem Material auf Korngrößenebene simuliert werden kann.:List of Acronyms VII
List of Latin Symbols IX
List of Greek Symbols XV
1 Introduction 1
1.1 Motivation for using realistic microstructures in Discrete Element Method (DEM) 1
1.2 Possibilities for using realistic mineral microstructures in DEM simulations . 4
1.3 Objective and disposition of the thesis . . . . . . . . . . . . . . . . . . . . 7
2 Background 9
2.1 Discrete Element Method (DEM) . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1.1 Fundamentals of the Discrete Element Method (DEM) . . . . . . . . 9
2.1.2 Applications of DEM in comminution science . . . . . . . . . . . . . 21
2.1.3 Limitations of DEM in comminution science . . . . . . . . . . . . . . 26
2.2 Quantitative Microstructural Analysis . . . . . . . . . . . . . . . . . . . . . 29
2.2.1 Fundamentals of the Quantitative Microstructural Analysis . . . . . . 29
2.2.2 Applied QMA in mineral processing . . . . . . . . . . . . . . . . . . 49
2.2.3 Applicability of the QMA for the synthesis of realistic microstructures 49
3 Synthesis of realistic mineral microstructures for DEM simulations 51
3.1 Development of a computer-assisted QMA for the analysis of real and synthetic
mineral microstructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
3.1.1 Fundamentals of the computer-assisted QMA . . . . . . . . . . . . 53
3.1.2 The requirements for the false-color image. . . . . . . . . . . . . . 54
3.1.3 The conversion of a given real mineral microstructure into a false-color
image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.1.4 Implementation of the point, line, and area analysis . . . . . . . . . 59
3.1.5 Selection of appropriate QMA parameters for analyzing two-dimensional
microstructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
3.1.6 Summary of the principles of the adapted Quantitative Microstructural
Analysis (QMA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.2 Analysis of possible strategies for the microstructure synthesis . . . . . . . . 71
3.3 Implementation of the drawing method . . . . . . . . . . . . . . . . . . . . 76
3.3.1 Drawing of a single grain . . . . . . . . . . . . . . . . . . . . . . . 77
XVIII List of Greek Symbols
3.3.2 Drawing of multiple grains, which form a synthetic microstructure . . 81
3.3.3 Synthesizing mineral microstructures consisting of multiple phases . 85
3.4 The final program for microstructure analysis and synthesis . . . . . . . . . 89
3.4.1 Synthesis and analysis of an example microstructure . . . . . . . . . 90
3.4.2 Procedure for generating a realistic synthetic microstructure of a given
real microstructure . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
4 Validation of the synthesis approach 103
4.1 Methodical considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
4.1.1 The basic idea of the validation procedure . . . . . . . . . . . . . . 103
4.1.2 The experimental realizations . . . . . . . . . . . . . . . . . . . . . 108
4.2 Basic indenter test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
4.2.1 Considerations for the basic indenter test . . . . . . . . . . . . . . . 109
4.2.2 Realization and evaluation of the real basic indenter test . . . . . . . 114
4.2.3 Realization and evaluation of the simulated basic indenter test . . . 127
4.2.4 Conclusions on the basic indenter test . . . . . . . . . . . . . . . . . 138
4.3 Extended indenter test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
4.3.1 Basic considerations for the extended indenter test . . . . . . . . . . 139
4.3.2 Realization and evaluation of the real extended indenter test . . . . 142
4.3.3 Realization and evaluation of the simulated extended indenter test . 154
4.3.4 Conclusions on the extended indenter test . . . . . . . . . . . . . . 171
4.4 Particle bed test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
4.4.1 Basic considerations for the particle bed test . . . . . . . . . . . . . 173
4.4.2 Realization and evaluation of the real particle bed test . . . . . . . . 176
4.4.3 Realization and evaluation of the simulated particle bed test . . . . . 188
4.4.4 Conclusions on the particle bed test . . . . . . . . . . . . . . . . . . 203
5 Conclusions and directions for future development 205
6 References 211
List of Figures 229
List of Tables 235
Appendix 237 / This research aims to make it possible to use realistic mineral microstructures in simulations of mineral processing. In particular, comminution processes, such as the crushing and grinding of raw mineral materials, are highly aff ected by the mineral microstructure, since the texture and structure of the many grains and their micromechanical properties determine the macroscopic fracture behavior. To illustrate this, consider a mineral material that essentially consists of grains of two diff erent mineral phases, such as quartz and feldspar. If the micromechanical properties of these two phases are diff erent, this will likely have an impact on the macroscopic fracture behavior. Assuming that the grains of one of the minerals break at lower loads, it is likely that a crack through a stone of that material will spread through the weaker grains. In fact, this is an important property for ore processing. In order to extract valuable minerals from an ore, it is important to liberate them from the commercially worthless material in which they are found. For this, it is essential to know and understand how the material breaks at grain-size level.
To be able to simulate this breakage, it is important to use realistic models of the mineral microstructures. This study demonstrates how such realistic two-dimensional microstructures can be generated on the computer based on quantitative microstructural analysis. Furthermore, the study shows how these synthetic microstructures can then be incorporated into the well-established discrete element method, where the breakage of mineral material can be simulated at grain-size level.:List of Acronyms VII
List of Latin Symbols IX
List of Greek Symbols XV
1 Introduction 1
1.1 Motivation for using realistic microstructures in Discrete Element Method (DEM) 1
1.2 Possibilities for using realistic mineral microstructures in DEM simulations . 4
1.3 Objective and disposition of the thesis . . . . . . . . . . . . . . . . . . . . 7
2 Background 9
2.1 Discrete Element Method (DEM) . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1.1 Fundamentals of the Discrete Element Method (DEM) . . . . . . . . 9
2.1.2 Applications of DEM in comminution science . . . . . . . . . . . . . 21
2.1.3 Limitations of DEM in comminution science . . . . . . . . . . . . . . 26
2.2 Quantitative Microstructural Analysis . . . . . . . . . . . . . . . . . . . . . 29
2.2.1 Fundamentals of the Quantitative Microstructural Analysis . . . . . . 29
2.2.2 Applied QMA in mineral processing . . . . . . . . . . . . . . . . . . 49
2.2.3 Applicability of the QMA for the synthesis of realistic microstructures 49
3 Synthesis of realistic mineral microstructures for DEM simulations 51
3.1 Development of a computer-assisted QMA for the analysis of real and synthetic
mineral microstructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
3.1.1 Fundamentals of the computer-assisted QMA . . . . . . . . . . . . 53
3.1.2 The requirements for the false-color image. . . . . . . . . . . . . . 54
3.1.3 The conversion of a given real mineral microstructure into a false-color
image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.1.4 Implementation of the point, line, and area analysis . . . . . . . . . 59
3.1.5 Selection of appropriate QMA parameters for analyzing two-dimensional
microstructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
3.1.6 Summary of the principles of the adapted Quantitative Microstructural
Analysis (QMA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.2 Analysis of possible strategies for the microstructure synthesis . . . . . . . . 71
3.3 Implementation of the drawing method . . . . . . . . . . . . . . . . . . . . 76
3.3.1 Drawing of a single grain . . . . . . . . . . . . . . . . . . . . . . . 77
XVIII List of Greek Symbols
3.3.2 Drawing of multiple grains, which form a synthetic microstructure . . 81
3.3.3 Synthesizing mineral microstructures consisting of multiple phases . 85
3.4 The final program for microstructure analysis and synthesis . . . . . . . . . 89
3.4.1 Synthesis and analysis of an example microstructure . . . . . . . . . 90
3.4.2 Procedure for generating a realistic synthetic microstructure of a given
real microstructure . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
4 Validation of the synthesis approach 103
4.1 Methodical considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
4.1.1 The basic idea of the validation procedure . . . . . . . . . . . . . . 103
4.1.2 The experimental realizations . . . . . . . . . . . . . . . . . . . . . 108
4.2 Basic indenter test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
4.2.1 Considerations for the basic indenter test . . . . . . . . . . . . . . . 109
4.2.2 Realization and evaluation of the real basic indenter test . . . . . . . 114
4.2.3 Realization and evaluation of the simulated basic indenter test . . . 127
4.2.4 Conclusions on the basic indenter test . . . . . . . . . . . . . . . . . 138
4.3 Extended indenter test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
4.3.1 Basic considerations for the extended indenter test . . . . . . . . . . 139
4.3.2 Realization and evaluation of the real extended indenter test . . . . 142
4.3.3 Realization and evaluation of the simulated extended indenter test . 154
4.3.4 Conclusions on the extended indenter test . . . . . . . . . . . . . . 171
4.4 Particle bed test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
4.4.1 Basic considerations for the particle bed test . . . . . . . . . . . . . 173
4.4.2 Realization and evaluation of the real particle bed test . . . . . . . . 176
4.4.3 Realization and evaluation of the simulated particle bed test . . . . . 188
4.4.4 Conclusions on the particle bed test . . . . . . . . . . . . . . . . . . 203
5 Conclusions and directions for future development 205
6 References 211
List of Figures 229
List of Tables 235
Appendix 237
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:72835 |
| Date | 30 November 2020 |
| Creators | Klichowicz, Michael |
| Contributors | Lieberwirth, Holger, Powell, Malcolm, Technische Universität Bergakademie Freiberg |
| Publisher | OpenD |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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