Recent developments have provided the opportunity to recover valuable materials from AMD treatment; this is a sustainable approach that allows to reduce waste while generating incomes that balance the cost of the treatment. This book provides insights to innovative and affordable routes for AMD valorisation that can certainly motivate the mining industry to effectively manage their wastes and minimize environmental impact while generating jobs opportunities.
Table of Contents
Preface xiii
Part 1: Prediction and Prevention of AMD Formation 1
1 Management of Metalliferous Solid Waste and its Potential to Contaminate Groundwater: A Case Study of O’Kiep, Namaqualand South Africa 3
Innocentia G. Erdogan, Elvis Fosso-Kankeu, Seteno K.O. Ntwampe, Frans B. Waanders and Nils Hoth
List of Abbreviations 4
1.1 Introduction 4
1.2 CMMs: Overview and Challenges 5
1.3 Metalliferous Solid Waste 6
1.3.1 Stockpiled Overburden Materials 6
1.3.2 Stockpiled Metalliferous Waste 7
1.3.3 Metalliferous Tailings 8
1.4 Environmental and Social Impact of CMMs and MSW 10
1.5 Soil Contamination 12
1.6 Groundwater Contamination 12
1.7 Atmospheric Contamination 12
1.8 Metalliferous Solid Waste Management 13
1.9 Rehabilitation and Restoration Strategies 13
1.10 ARD Formation and Groundwater Contamination 14
1.11 Overview of Challenges Associated with CMMs 15
1.12 Conclusion 16
References 16
2 Mine Water Treatment and the Use of Artificial Intelligence in Acid Mine Drainage Prediction 23
Viswanath Ravi Kumar Vadapalli, Emmanuel Sakala, Gloria Dube and Henk Coetzee
List of Abbreviations 23
2.1 Acid Mine Drainage (AMD) 24
2.1.1 AMD Generation 24
2.1.2 Factors Controlling AMD Generation 25
2.2 Remediation of AMD 27
2.2.1 Introduction 27
2.2.2 Passive Treatment of AMD 27
2.2.3 Active Treatment of AMD 29
2.2.4 Challenges With Current AMD Treatment 32
2.2.5 Value Recovery From AMD Treatment 33
2.3 Prediction of AMD 34
2.3.1 Limitations of Predictive Tools 35
2.4 Application of Artificial Intelligence for AMD Quality Prediction 36
2.4.1 Introduction 36
2.4.2 Different AI Techniques Used to Predict AMD Quality 37
2.4.3 Limitations of AI Techniques in Prediction of AMD Quality 38
2.4.4 Case Study - Ermelo Coalfield, South Africa 39
2.5 Conclusions 40
References 41
3 The Prediction of Acid Mine Drainage Potential Using Mineralogy 49
Deshenthree Chetty, Olga Bazhko, Veruska Govender and Samuel Ramatsoma
3.1 Introduction 49
3.2 Mineralogical Approach for Prediction of AMD Potential 51
3.2.1 AMD Chemistry for Maximum Acid Generation or Consumption Potential 51
3.2.2 Mineral Modal Abundance 54
3.2.3 Mineral Reactivity 54
3.2.4 Mineral Liberation 56
3.2.5 Calculation of the AMD Potential 57
3.3 Application of the AMD Predictive Protocol 58
3.3.1 Experimental Procedures 59
3.3.2 Results and Discussion 60
3.4 Conclusions and Further Work 67
References 68
4 Oxidation Processes and Formation of Acid Mine Drainage from Gold Mine Tailings: A South African Perspective 73
Bisrat Yibas
4.1 Introduction 73
4.2 Weathering and Oxidation of the Witwatersrand Gold Tailings 74
4.3 Water Infiltration and Oxygen Diffusion vs Oxidation Processes 76
4.3.1 Hydrogeology of Tailings Storage Facilities 76
4.3.1.1 Introduction 76
4.3.1.2 Primary Hydraulic Characteristics 78
4.3.1.3 Geological Structures as Preferential Flow Paths 80
4.3.2 Oxygen Diffusion 82
4.4 Geochemical and Mineralogical Evolution 84
4.4.1 Tailings Geochemistry and Mineralogy 84
4.4.2 Pore Water Geochemistry 86
4.5 Discussion, Conclusion, and Recommendations 89
4.5.1 Discussion 89
4.5.1.1 Mapping of the Oxidation Zones in Tailings Dams 89
4.5.1.2 Hydrogeological Situation 90
4.5.1.3 Oxygen Diffusion With Depth 90
4.5.1.4 Mineralogical and Geochemical Evolution of Tailings 91
4.5.1.5 Evolution of Pore Water Chemistry 91
4.5.1.6 Oxidation Processes and Drainage Formation 91
4.5.2 Conclusions 92
4.5.3 Recommendations 93
Acknowledgements 93
References 94
Part 2: AMD Treatment 97
5 Technologies that can be Used for the Treatment of Wastewater and Brine for the Recovery of Drinking Water and Saleable Products 99
Tumelo Monty Mogashane, Johannes Philippus Maree, Munyaradzi Mujuru and Mabel Mamasegare Mphahlele-Makgwane
5.1 Introduction 100
5.1.1 Formation of Acid Mine Water 100
5.1.2 Water Volumes 100
5.1.3 Legislation 101
5.1.4 Government Initiatives 102
5.1.5 Required Criteria 103
5.2 Neutralization Technologies 103
5.2.1 Neutralization Using Lime 103
5.2.1.1 Conventional Treatment With Lime 103
5.2.1.2 High-Density Sludge Process 104
5.2.2 Limestone Neutralization 105
5.2.3 Limestone Handling and Dosing System 106
5.2.4 Utilization of Alkali in Mine Water for Removal of Iron(II) 107
5.2.5 Modeling 107
5.2.6 Lime/Limestone Neutralization 109
5.2.6.1 Description of the Process 109
5.2.6.2 Removal of H2SO4, Fe3+, and Al3+ with Limestone 110
5.2.6.3 Removal of H2SO4, Fe3+, Al3+, and Fe2+ with Limestone 111
5.3 Chemical Desalination 111
5.3.1 SAVMIN 111
5.3.2 Barium Sulfate Treatment Process 112
5.4 Membrane Processes 115
5.4.1 Reverse Osmosis 115
5.4.2 NF Technologies 117
5.4.3 High Recovery Precipitating Reverse Osmosis (HiPRO®) Process 117
5.4.4 Electrodialysis 120
5.4.5 Vibration Shear Enhanced Process 121
5.4.6 Multi-Effect Membrane Distillation 122
5.4.7 Forward Osmosis Desalination 122
5.4.8 Biomimetic Desalination - Aquaporin Proteins 123
5.4.9 Carbon Nanotube Distillation 123
5.5 Ion-Exchange Technologies 124
5.5.1 Introduction 124
5.5.2 Conventional Ion-Exchange 125
5.5.3 The GYP-CIX 125
5.5.4 KNeW 125
5.6 Biological Processes 126
5.6.1 Background 126
5.6.2 Biological Sulfate Reduction 127
5.6.3 Constructed Bioreactors 128
5.6.4 Paques Technologies 129
5.6.5 BioSURE Technology 130
5.6.6 The VitaSOFT Process 131
5.6.7 In Situ Reactor 132
5.6.8 Constructed Aerobic Wetlands 133
5.6.9 Permeable Reactive Barriers 133
5.6.10 General Aspects and Various Passive Technologies 133
5.7 Electrochemical Processes 135
5.7.1 Electrocoagulation 135
5.7.2 Nanoelectrochemical Process for the Treatment of AMD 135
5.8 Freezing-Based Technologies 136
5.8.1 Basics 136
5.8.2 Eutectic Freeze Crystallization 136
5.8.3 HybridICE™ Technology 136
5.9 Sludge Processing 137
5.9.1 Background 137
5.9.2 Recovery of Saleable Products or Raw Materials 138
5.10 Integrated Processes - ROC Process 138
5.10.1 Background 138
5.10.2 Process Description 139
5.11 Feasibility Models 140
5.11.1 Introduction 140
5.11.2 Feasibility of Individual Stages 142
5.11.2.1 Neutralization Technologies 142
5.11.2.2 Desalination Technologies 143
5.11.2.3 Brine Treatment 149
5.11.2.4 Product Recovery 149
5.11.3 Feasibility of Various Process Configurations 149
5.12 Conclusions 150
Acknowledgements 150
References 151
Part 3: Recovery of Values from AMD 157
6 Recovery of Ochers from Acid Mine Drainage Treatment: A Geochemical Modeling and Experimental Approach 159
Khathutshelo Netshiongolwe, Yongezile Mhlana, Alseno Mosai, Heidi Richards, Luke Chimuka, Ewa Cukrowska and Hlanganani Tutu
6.1 Introduction 159
6.2 Methodology 162
6.2.1 Simulation Studies - Model Setup as an Experimental Design Approach 162
6.2.2 Experimental Studies 164
6.2.2.1 Experiment 1 164
6.2.2.2 Using NaOH as a Neutralizing Agent 165
6.2.2.3 Addition of Ferrocyanide to Mineral Salts Used to Simulate AMD (Experiment 2) 165
6.2.2.4 Using MgCO3 as a Neutralizing Agent 166
6.2.3 Characterization of Fe Oxides 166
6.3 Results and Discussion 166
6.3.1 Simulation Studies 166
6.3.1.1 Individual Neutralizing Agents 166
6.3.1.2 Combined Neutralizing Agents 167
6.3.1.3 Equilibrating with CO2 168
6.3.1.4 Equilibrating with O2 168
6.3.1.5 Fixed pH 169
6.3.1.6 Varying Temperature 169
6.3.1.7 Varying Concentrations of Neutralizing Agents 169
6.3.2 Characterization of HDS 169
6.3.2.1 Aims and Dry Matter 169
6.3.2.2 Physical Characterization of HDS 170
6.3.2.3 Chemical Characterization of HDS 170
6.3.2.4 Mineralogy and Chemical Composition of HDS 170
6.3.3 Experimental Studies 172
6.3.3.1 Procedure Description 172
6.3.3.2 Formation of Precipitates 172
6.3.3.3 Characterization of Fe Precipitates 182
6.3.3.4 Application in Paintings and Artwork 183
6.3.3.5 Water Chemistry 183
6.4 Indicative Cost Analysis 184
6.5 Conclusion 185
Acknowledgements 185
References 185
7 Innovative Routes for Acid Mine Drainage (AMD) Valorization: Advocating for a Circular Economy 189
Vhahangwele Masindi and Memory Tekere
7.1 Introduction 190
7.1.1 Problem Description 190
7.1.2 Physico-Chemical-Microbiological Properties of AMD 191
7.2 Health Effects Associated with Contaminants in AMD 193
7.3 Abatement of AMD 194
7.4 Techniques for AMD Treatment 195
7.4.1 Overview 195
7.4.2 Chemical Precipitation 195
7.4.3 Adsorption 197
7.4.4 Filtration 198
7.4.4.1 Introduction to Membrane Technologies 198
7.4.5 Phyto Remediation 201
7.4.5.1 Theory of the MD Process 201
7.4.6 Phytoremediation 202
7.5 Valorization of AMD 202
7.5.1 Aims of Valorization 202
7.5.2 Reclamation of Drinking Water 203
7.5.3 Recovery of Valuable Minerals 203
7.5.4 Synthesis of Valuable Minerals 204
7.6 Case Study 204
7.7 Challenges Relating to Valorization 208
7.8 Conclusions and Future Perspectives 208
References 209
8 Recovery of Critical Raw Materials from Acid Mine Drainage (AMD): The EIT-Funded MORECOVERY Project 219
Carlos Ruiz Cánovas, Jose Miguel Nieto, Francisco Macías, Maria Dolores Basallote, Manuel Olías, Rafael Pérez-López and Carlos Ayora
8.1 Introduction 219
8.2 Recovery of CRMs from AMD 222
8.3 Upscaling of Successful Technologies and Economic Suitability 224
8.4 Coupling Environmental and Resources Policy: The EIT-Funded MORECOVERY Project 225
Acknowledgements 231
References 231
9 Deriving Value from Acid Mine Drainage 235
M. van Rooyen and P.J. van Staden
9.1 Introduction 235
9.2 AMD Formation 237
9.3 AMD Treatment Options 238
9.3.1 General Philosophy 238
9.3.2 High-Density Sludge Neutralization of AMD 239
9.3.3 Sulfate Removal Options 240
9.3.3.1 Reverse Osmosis 240
9.3.3.2 Ettringite Precipitation 243
9.3.3.3 Barium Carbonate Addition 245
9.3.3.4 Biological Sulfate Reduction 246
9.4 Deriving Value from AMD 247
9.4.1 Fit-for-Use Water 247
9.4.1.1 The Cascade Model 247
9.4.1.2 Water Suitable for Irrigation 248
9.4.1.3 Water Suitable for Industrial Use 249
9.4.1.4 Water Suitable for Environmental Discharge 249
9.4.1.5 Water Suitable for Sanitation 249
9.4.1.6 Potable Water 249
9.4.1.7 Cooling Water 249
9.4.1.8 Boiler Water 250
9.4.2 By-Products from AMD Treatment Processes 251
9.4.2.1 Overview 251
9.4.2.2 Gypsum Containing Products 251
9.4.2.3 High-Value Iron-Bearing Products 252
9.4.2.4 Uranium and Base Metals 253
9.4.2.5 Hydrogen 255
9.5 Synopsis 255
9.5.1 AMD Remediation 255
9.5.2 Deriving Value From AMD 256
References 259
10 Rare Earth Elements - A Treasure Locked in AMD? 263
Leon Krüger
10.1 AMD - Annoyance or Resource 263
10.2 Rare Earths - The Almost Forgotten Elements! 264
10.3 Characteristics - What is with the f-Orbitals? 265
10.4 Applications - Sweating the Unique Characteristics 271
10.4.1 Introduction 271
10.4.2 Rare Earths as Process Enablers 271
10.4.2.1 Catalysis 271
10.4.2.2 Physical Metallurgy 276
10.4.2.3 Glass and Ceramic Industries 277
10.4.2.4 Medicine and Health Care 280
10.4.3 Rare Earths as Technology Building Blocks 283
10.4.3.1 Permanent Magnets 283
10.4.3.2 Energy Storage 287
10.4.3.3 Phosphors 293
10.4.3.4 Glass Additives 295
10.4.3.5 Lasers 298
10.5 Occurrence - From Magma to AMD 303
10.6 REEs - From AMD to High Technology? 308
Acknowledgements 308
References 309
11 Opportunities and Challenges of Re-Mining Mine Water for Resources 315
Martin Mkandawire
11.1 Introduction 315
11.2 Mine Water and Drainages 316
11.2.1 Mine Water in Context of This Chapter 316
11.2.2 General Mine Water Chemistry 317
11.2.3 Types of Mine Water Sources 317
11.2.3.1 Overview 317
11.2.3.2 Flooded Underground Mine Pool 318
11.2.3.3 Flooded Opencast Lakes 318
11.2.3.4 Leachates 319
11.2.4 Drainages of Mine Water 321
11.2.4.1 Acid Mine Drainage 321
11.2.4.2 Alkali Mine Drainage 322
11.3 Potential Extractable Resources 323
11.3.1 Water Supply 323
11.3.1.1 Opportunities 323
11.3.1.2 Applicable Extraction Methods 323
11.3.1.3 Challenges 324
11.3.1.4 Counter Options 324
11.3.2 Thermal Resource 325
11.3.2.1 Opportunities 325
11.3.2.2 Applicable Extraction Methods 326
11.3.2.3 Challenges 328
11.3.2.4 Counter Options 328
11.3.3 Electricity Generation Prospects 330
11.3.3.1 Opportunities 330
11.3.3.2 Applicable Extraction Methods 330
11.3.3.3 Challenges 334
11.3.3.4 Counter Options 335
11.3.4 Mineral Resource Extraction 335
11.3.4.1 Opportunities 335
11.3.4.2 Applicable Extraction Methods 336
11.3.5 Re-Mining Mine Water Treatment Sludge 336
11.3.5.1 Opportunities 336
11.3.5.2 Applicable Extraction Methods 340
11.3.5.3 Challenges 341
11.3.5.4 Counter Options 342
11.3.6 Mine Methane Gas Extraction 342
11.3.6.1 Opportunities 342
11.3.6.2 Applicable Extraction Methods 343
11.3.6.3 Challenges 346
11.3.6.4 Counter Options 347
11.4 Conclusion 347
References 347
Index 351
