Separation Hydrometallurgy of Rare Earth Elements (eBook)

Dr. Jack Zhang is Senior Researcher, Mineral Processing and Hydrometallurgy, at the Saskatchewan Research Council (SRC). His areas of focus include applied R&D and custom testing for uranium, potash, rare earth, diamond, gold, base metals, and mine water treatment. Professor Dequian Li is a the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences and has been engaged in the study of separation chemistry and clean hydrometallurgical engineering of rare earths for the over 50 years. Dr. Baodong Zhaois the VP of Metallurgy at the Great Western Mineral Group Ltd. He has more than 20 years of experience in metallurgical engineering and project technical management within both R&D and operations environments. Dr. Bryan Schreiner is the Chief Geoscientist at the Mining and Minerals Division of the Saskatchewan Research Council (SRC).

Preface 8
Acknowledgements 10
Contents 12
Chapter 1: Rare Earth Elements and Minerals 18
1.1 Rare Earth Elements (REEs) 18
1.1.1 Scandium (Sc) 19
1.1.2 Yttrium (Y) 19
1.1.3 Lanthanum (La) 19
1.1.4 Cerium (Ce) 20
1.1.5 Praseodymium (Pr) 20
1.1.6 Neodymium (Nd) 20
1.1.7 Promethium (Pm) 20
1.1.8 Samarium (Sm) 20
1.1.9 Europium (Eu) 21
1.1.10 Gadolinium (Gd) 21
1.1.11 Terbium (Tb) 21
1.1.12 Dysprosium (Dy) 21
1.1.13 Holmium (Ho) 21
1.1.14 Erbium (Er) 22
1.1.15 Thulium (Tm) 22
1.1.16 Ytterbium (Yb) 22
1.1.17 Lutetium (Lu) 22
1.2 REE Electronic Configurations and Lanthanide Contraction 22
1.2.1 REE Electronic Configurations 22
1.2.2 Lanthanide Contraction 24
1.2.3 Physicochemical Properties of Rare Earth Metals 25
1.3 Applications of Rare Earth Elements 27
1.3.1 Metallurgy and Machinery 27
1.3.2 Petroleum and Chemical Industry 27
1.3.3 Glass and Ceramics 28
1.3.4 Phosphors 29
1.3.5 Permanent Magnets 29
1.4 Rare Earth Minerals 30
1.5 Resource and Production 31
1.6 Chemical Technologies for REE Separation 31
1.6.1 Ce Separation with Oxidation Process 32
1.6.2 Phosphor Grade Eu2O3 Production Using Zinc Reduction-Alkalinity Process 33
References 34
Chapter 2: Rare Earth Beneficiation and Hydrometallurgical Processing 35
2.1 RE Mineral Processing Technology 35
2.1.1 Gravity Separation 35
2.1.2 Flotation 36
2.1.3 Magnetic Separation 36
2.2 Rare Earth Ore Beneficiation 37
2.2.1 Bastnaesite 37
2.2.1.1 Eastern China WS Rare Earth Deposit 38
2.2.1.2 South West China MN Rare Earth Deposit 38
2.2.2 Monazite 40
2.2.2.1 Monazite Placers 40
2.2.2.2 Weathered Crust Monazite Deposit 41
2.2.3 Xenotime 42
2.2.3.1 Xenotime Separation from Coastal Placers 44
2.2.3.2 Xenotime Separation from Weathered Crust 45
2.2.4 Ion-Adsorbed Type Rare Earth Deposits 45
2.2.5 Baiyun Obo Rare Earth Deposit 47
2.2.5.1 Calcination-Magnetic Separation-Flotation Process 48
2.2.5.2 Flotation-Low Magnetic Separation Process 49
2.2.5.3 Low Magnetic Separation-Flotation-High Magnetic Separation Process 50
2.2.5.4 Low Magnetic Separation-High Magnetic Separation-Flotation Process 50
2.2.6 WS Rare Earth Deposit 53
2.2.7 MN Maoniuping Rare Earth Deposit 54
2.2.8 Mountain Pass Rare Earth Deposit 54
2.2.9 Mount Weld 57
2.2.10 Summary of the Rare Earth Beneficiation Processes 58
2.3 Hydrometallurgical Processing of Rare Earth Mineral Concentrate 58
2.3.1 H2SO4 Acid-Roasting and Water Leaching 60
2.3.2 HCl Acid Leaching 62
2.3.3 HNO3 Acid Leaching 64
2.3.4 Na2CO3 Roasting 64
2.3.5 NaOH Decomposing 65
2.3.6 Chlorination 66
2.3.7 Leaching of Ion-adsorbing Type of Rare Earth Clay 67
2.3.8 Summary 68
References 68
Chapter 3: Solvent Extraction in Metal Hydrometallurgy 71
3.1 Solvent Extraction Basics 71
3.1.1 Extraction 71
3.1.2 Scrubbing/Washing 73
3.1.3 Stripping 73
3.1.4 Basic Solvent Extraction Separation Process 74
3.1.5 Cascade Solvent Extraction Process 74
3.2 Liquid-Liquid Equilibrium 76
3.2.1 Equilibrium and Nernst´s Distribution Law 76
3.2.1.1 Distribution Constant and Distribution Ratio 77
3.2.2 Distribution Data 78
3.2.2.1 Distribution Isotherm Method 78
3.2.2.2 Mathematic Model Method 79
3.2.3 Separation Factor 79
3.2.4 Extraction Percentage and Extraction Ratio 80
3.3 Solubility Rules in Solvent Extraction 81
3.3.1 Classification of Solvent 81
3.3.1.1 N Type of Solvent 81
3.3.1.2 A Type of Solvent 82
3.3.2 B Type of Solvent 82
3.3.2.1 AB Type of Solvent 82
3.3.3 Solvent Miscibility 82
3.3.4 Water-Solvent Mutual Solubility 83
3.4 Solute-Solvent Interactions 83
3.4.1 Metal in Aqueous Solution 84
3.4.2 Metal in Organic Solution 85
3.5 Solvent Extraction System 86
3.5.1 Acidic Solvent Extraction 87
3.5.2 Ion Pair Solvent Extraction 88
3.5.3 Solvating Solvent Extraction 89
3.5.4 Synergistic Solvent Extraction 91
3.6 Kinetics of Solvent Extraction 91
3.6.1 Diffusion Controlled Solvent Extraction 92
3.6.2 Reaction Controlled Solvent Extraction 93
3.7 Factors Affecting Metal Solvent Extraction 94
References 94
Chapter 4: Rare Earth Solvent Extraction Systems 95
4.1 HEH/EHP Solvent Extraction System 95
4.1.1 HEH/EHP-HNO3 System 96
4.1.2 P507-HCl System 100
4.1.3 P507-H2SO4 System 105
4.1.4 Saponification 108
4.1.5 Full Rare Earth Separation Using P507 111
4.1.6 Light Rare Earth Element Separation Using P507 113
4.1.7 Light and Heavy Rare Earth Element Separation Using P507 114
4.1.8 Heavy Rare Earth Separation Using P507 115
4.1.9 Ion-Adsorptive Rare Earth Separation Using P507 117
4.1.10 Ce4+ Separation by P507-H2SO4 System 118
4.2 HDEHP Solvent Extraction System 123
4.2.1 HDEHP Extracting Rare Earths 124
4.2.2 Factors Affecting Rare Earth Extraction with HDEHP 127
4.2.2.1 Aqueous-Phase Acidity 127
4.2.2.2 Saponification 128
4.2.2.3 Diluent 128
4.2.2.4 Rare Earth Ion Radius 129
4.2.2.5 Feed Rare Earth Concentration 129
4.2.2.6 Temperature 130
4.2.3 Group Separation of Mixed Rare Earth 130
4.2.4 Individual Separation of Light Rare Earth 132
4.2.5 Individual Separation of Middle Rare Earths 135
4.2.6 Scandium Recovery 136
4.2.7 Th and Other Non-rare Earth Impurity Separation 138
4.3 HBTMPP Extraction System 138
4.3.1 HBTMPP Extracting Rare Earths 139
4.3.2 HBTMPP Extracting Sc3+ and Fe3+ 141
4.3.3 HBTMPP Extracting Th4+ 142
4.4 TBP Solvent Extraction System 143
4.4.1 TBP Extracting Rare Earth 143
4.4.2 TBP Extracting Water and Acid 146
4.4.3 TBP Extracting Uranium and Thorium 147
4.4.4 TBP Extracting Scandium 149
4.5 P350 Solvent Extraction System 149
4.5.1 Factors Affecting Rare Earth Extraction Using P350 (Xu 2003 Li 2011)
4.5.1.1 Acid 151
4.5.1.2 Salting Agent (Xu and Yuan 1987) 152
4.5.1.3 Rare Earth Concentration 152
4.5.1.4 P350 Concentration 154
4.5.1.5 Other Factors 154
4.5.2 Production of High-Purity La2O3 154
4.5.3 Pr-Nd Separation Process 155
4.5.4 P350 Extracting Scandium 155
4.6 Cyanex 923 Solvent Extraction System 158
4.6.1 Cyanex 923 Extracting RE3+ in HNO3 Acid Solution 158
4.6.2 Extraction and Stripping of Yb from H2SO4 Solution (Wang et al. 2006) 160
4.6.3 Ce4+ and Th4+ Separation 163
4.7 Naphthenic Acid Extraction System 165
4.7.1 Naphthenic Acid Extracting Rare Earth 166
4.7.2 Separation and Purification of High-Purity Y 169
4.7.3 Impurity Removal 175
4.7.4 Rare Earth Recovery from Low-Concentration Solution 176
4.7.5 Effects of Additives on Naphthenic Acid Extraction System 177
4.8 Amine Extraction System 178
References 181
Chapter 5: Cascade Solvent Extracting Principles and Process Design 186
5.1 Introduction 186
5.2 Assumptions of Xu´s Cascade Extraction Principles 189
5.3 Countercurrent Solvent Extraction Process 190
5.3.1 Extraction Residual Fraction phi and Recovery Y 190
5.3.2 Concentrating Factor and Purity 192
5.3.3 Example of Application 193
5.4 Cross Flow Solvent Extraction Process 196
5.5 Fractional Solvent Extraction Process 197
5.5.1 Material Balance of Aqueous Feeding System 197
5.5.2 Material Balance of Organic Feeding System 200
5.5.3 Concentrating Factor 202
5.5.4 Extraction Residual Fraction 202
5.5.5 Example of Application 203
5.6 Extrema Equations 204
5.6.1 Aqueous Feeding System 204
5.6.2 Organic Feeding System 206
5.7 Number of Stages of Fractional Solvent Extraction 206
5.7.1 System with Constant Extraction Factor of Individual Solute 206
5.7.2 System with Constant Extraction Factor of Mixed Solutes 208
5.7.2.1 Purity Equilibrium Line Equation 208
5.7.2.2 Purity Operating Line Equation in Extraction 209
5.7.2.3 Purity Operating Line Equation in Scrubbing 210
5.7.2.4 The Number of Extraction Stages 211
5.7.2.5 The Number of Scrubbing Stages 212
5.7.2.6 Extrema of Extraction Factor 213
5.8 Optimum Equations 214
5.8.1 Optimum Extraction Factor 214
5.8.2 Optimum Reflux Ratio Equation 215
5.8.3 Controlling Conditions and Variables 216
5.8.3.1 Aqueous Feeding System 216
5.8.3.2 Organic Feeding System 217
5.8.3.3 Determination of Optimum Extraction Factor 218
5.9 Application of the Extrema Equations 220
5.10 Design Procedure of Optimum Rare Earth Cascade Solvent Extraction Process 221
5.10.1 Extraction System Determination and Separation Factor Measurement 221
5.10.2 Separation Target Specification 222
5.10.2.1 A as Major Product 223
5.10.2.2 B as Major Product 223
5.10.2.3 A and B both as Major Products 224
5.10.3 Optimum Process Parameter Determination 224
5.10.4 Determination of the Number of Stages 226
5.10.5 Determination of Flow Ratio 226
5.10.6 Material Distribution and Balance Table Construction 226
5.10.7 Overall Process Evaluation 228
5.10.8 Example of Optimum Rare Earth Separation Process Design 228
5.11 Circulating Solvent Extraction 236
5.11.1 Full Circulation 236
5.11.2 Partial Circulation 236
5.12 Process Design of Three-Outlet Process 238
5.12.1 Outlet Fraction, Purity, and Recovery 238
5.12.1.1 Basic Equations 238
5.12.1.2 Separation Target Specification 240
5.12.2 Amount of Extraction So 244
5.12.2.1 Material Balance of Three-Outlet System 244
5.12.2.2 Minimum Amount of Extraction Rule 246
5.12.3 The Number of Three-Outlet Process Stages 247
5.12.3.1 The Third Outlet Located in Extraction 247
5.12.3.2 The Third Outlet Located in Scrubbing 249
5.12.4 Example of Three-Outlet Process Design 250
5.12.5 Three-Outlet Process Features 253
5.13 Fuzzy Linkage Extraction 254
5.13.1 Introduction 254
5.13.2 Features of Fuzzy Linkage Separation Process 255
References 256
Chapter 6: Rare Earth Solvent Extraction Equipment 257
6.1 Classification of Solvent Extraction Equipment 257
6.1.1 Stage-Type Extractor 257
6.1.2 Column-Type Extractors 258
6.1.2.1 Packed Tower 258
6.1.2.2 Pulse Column 259
6.1.2.3 Rotating Disc Contactor 260
6.1.2.4 Tray Column 261
6.1.3 Centrifugal Extractors 262
6.2 Selection Criteria of Extractors 262
6.3 Basics of Extractor Design 265
6.3.1 Rate of Extraction (N) 265
6.3.2 Height Equivalent of a Theoretical Stage 265
6.3.3 Mass Transfer Unit 266
6.3.4 Stage Efficiency 268
6.3.5 Axial Mixing 268
6.3.6 Dispersed Phase Holdup 269
6.3.7 Equipment Efficiency 269
6.4 Design of Mixer-Settler 269
6.4.1 Number of Stages 269
6.4.2 Design of Mixer 270
6.4.3 Design of Settler 271
6.5 Design of Packed Column 271
6.5.1 Determination of the Dispersed Phase 272
6.5.2 Packing Material 272
6.5.3 Column Diameter 272
6.5.4 Column Height 273
6.5.5 Testing and Scale-Up 273
References 273