Elvis Fosso-Kankeu, PhD, is a professor in the Department of Metallurgy, Faculty of Engineering and Built Environment, University of Johannesburg, Doornfontein, South Africa. His research focuses on the hydrometallurgical extraction of metal from solid phases, the prediction of pollutant dispersion from industrial areas, and the development of effective and sustainable methods for the removal of inorganic and organic pollutants from polluted water. He has published more than 220 papers including journal articles, books, book chapters, and conference proceedings papers. He has won several research awards including the NSTF Award (National Science and Technology Forum: largest science, engineering, technology, and innovation awards in South Africa and are known as the “Science Oscars” of recent times) Engineering Research Capacity Development, in 2019.Bhekie B. Mamba, PhD, is the executive dean of the College of Science, Engineering, and Technology, the University of South Africa. Prof Mamba is a visionary and has occupied several leadership positions including being a Professor and Head at the Department of Applied Chemistry at the University of Johannesburg, and the Director of the Institute of Nanotechnology and Water Research at the University of Johannesburg. He has published about seven book chapters, over 250 journal articles, about 12 technical reports, and over 50 papers in conference proceedings. His general research interest involves developing advanced technologies for water treatment, which include nanotechnology and membrane technology.Antoine F. Mulaba-Bafubiandi is emeritus professor at the University of Johannesburg, South Africa. He is the first Head of School of Mining, Metallurgy and Chemical Engineering, Faculty of Engineering and The Built Environment, and the founding chair of the Mineral Processing and Technology Research Center (MPTRC). One of his current research projects involves the use of biomass for the extraction of gold (via hydrometallurgy) and the reduction of ferromanganese ores (via pyrometallurgy).

• Preface xiii1 Optimization of the Mechanical Comminution -- The Crushing Stage 1Ngonidzashe Chimwani1.1 Introduction 21.2 The Role of Crushers 51.3 Conclusion 312 Challenges Related to the Flotation Process of Complex Phosphate Ores 41Nheta Willie and Hlahane Morake D.2.1 Introduction to the Geology of Complex Phosphate Ores 422.2 Phosphate Rock Beneficiation Processes 442.3 Froth Flotation of Sedimentary Phosphate Ore 482.4 Challenges Facing Flotation of Phosphate Rock 542.5 Future Research Directions 582.6 Conclusion 583 Increasing Ionic Strength and Oxyhydroxo Species in Process Water on the Floatability of Chalcopyrite and Pentlandite for a Selected Cu--Ni Bearing Ore Flotation 65Malibongwe S. Manono, Katlego M. Matibidi, Lisa L. October, Catherine K. Thubakgale and Kirsten C. Corin3.1 Introduction 663.2 Materials and Methods 693.3 Results and Discussion 723.4 Froth Column Studies from a Two-Froth Column 784 Relating the Flotation Response of Pyrrhotite to the Adsorption of Sodium Carboxymethyl Cellulose and Sodium Isobutyl Xanthate on its Surface in Process Water of a Degrading Quality 87Malibongwe S. Manono, Lisa L. October and Kirsten C. Corin4.1 Introduction 884.2 Experimental Methods 914.3 Results and Discussion 974.4 Conclusions 1075 Simulated Short Cycle Water Recirculation on the Flotation Performance of a UG2 Cu--Ni--PGM Ore 111Malibongwe S. Manono, Michael S. Ngau and Kirsten C. Corin5.1 Introduction 1125.2 Materials and Methods 1155.3 Results and Discussion 1265.4 Conclusions 1376 Complexity of Chalcopyrite Mineral Affecting Copper Recovery During Leaching 145Kolela J. Nyembwe, Frans Waanders, Martin Mkandawire, Bhekie Mamba and Elvis Fosso-Kankeu6.1 Introduction 1466.2 CuFeS2 Crystal Structure 1476.3 Application of Dissolution/Leaching of Chalcopyrite 1486.4 Challenges Associated with Copper Dissolution from the Chalcopyrite Mineral 1496.5 H2SO4-Fe2(SO4)3-FeSO4-H2O Speciation 1536.6 Parameters Affecting Dissolution 1556.7 Thermodynamic Considerations 1606.8 CuFeS2 Phases Conversion/Copper Sulfide (Cu-S) Intermediate Phases 1616.9 Conclusion 1727 Fe3+-Fe2+ Redox Cycle Peculiarity in the Acid Dissolution of Copper--Cobalt Complex Ores 179Bienvenu Mbuya, Léon Zeka and Antoine F. Mulaba-Bafubiandi7.1 Introduction 1807.2 Conventional Leaching of Copper--Cobalt Minerals 1827.3 Fe3+--Fe2+ Redox Cycle in the Dissolution of Mixed Oxidized and Sulfide Minerals 2027.4 Application of Mineral--Mineral Leaching Process to the Dissolution of Complex Ores 2087.5 Conclusion 2128 Rare Earth Elements (REEs) in Complex Ores and Spent Materials: Processing Technologies and Relevance in the Global Energy Transition 217Theophilus Ile Ojonimi, Tina Phiri Chanda, Ilemona C. Okeme, Ferdinand Asuke and Antoine F. Mulaba-Bafubiandi8.1 Introduction 2188.2 The Chemistry of REEs 2208.3 REE Minerals and Deposit Types 2208.4 REE Ore Mining and Processing Technologies 2238.5 Relevance of REEs in Energy Transition 2398.6 Conclusion 241References 241Index 249

Elvis Fosso-Kankeu, PhD, is a professor in the Department of Metallurgy, Faculty of Engineering and Built Environment, University of Johannesburg, Doornfontein, South Africa. His research focuses on the hydrometallurgical extraction of metal from solid phases, the prediction of pollutant dispersion from industrial areas, and the development of effective and sustainable methods for the removal of inorganic and organic pollutants from polluted water. He has published more than 220 papers including journal articles, books, book chapters, and conference proceedings papers. He has won several research awards including the NSTF Award (National Science and Technology Forum: largest science, engineering, technology, and innovation awards in South Africa and are known as the “Science Oscars” of recent times) Engineering Research Capacity Development, in 2019.Bhekie B. Mamba, PhD, is the executive dean of the College of Science, Engineering, and Technology, the University of South Africa. Prof Mamba is a visionary and has occupied several leadership positions including being a Professor and Head at the Department of Applied Chemistry at the University of Johannesburg, and the Director of the Institute of Nanotechnology and Water Research at the University of Johannesburg. He has published about seven book chapters, over 250 journal articles, about 12 technical reports, and over 50 papers in conference proceedings. His general research interest involves developing advanced technologies for water treatment, which include nanotechnology and membrane technology.Antoine F. Mulaba-Bafubiandi is emeritus professor at the University of Johannesburg, South Africa. He is the first Head of School of Mining, Metallurgy and Chemical Engineering, Faculty of Engineering and The Built Environment, and the founding chair of the Mineral Processing and Technology Research Center (MPTRC). One of his current research projects involves the use of biomass for the extraction of gold (via hydrometallurgy) and the reduction of ferromanganese ores (via pyrometallurgy).

• Preface xiii1 Optimization of the Mechanical Comminution -- The Crushing Stage 1Ngonidzashe Chimwani1.1 Introduction 21.2 The Role of Crushers 51.3 Conclusion 312 Challenges Related to the Flotation Process of Complex Phosphate Ores 41Nheta Willie and Hlahane Morake D.2.1 Introduction to the Geology of Complex Phosphate Ores 422.2 Phosphate Rock Beneficiation Processes 442.3 Froth Flotation of Sedimentary Phosphate Ore 482.4 Challenges Facing Flotation of Phosphate Rock 542.5 Future Research Directions 582.6 Conclusion 583 Increasing Ionic Strength and Oxyhydroxo Species in Process Water on the Floatability of Chalcopyrite and Pentlandite for a Selected Cu--Ni Bearing Ore Flotation 65Malibongwe S. Manono, Katlego M. Matibidi, Lisa L. October, Catherine K. Thubakgale and Kirsten C. Corin3.1 Introduction 663.2 Materials and Methods 693.3 Results and Discussion 723.4 Froth Column Studies from a Two-Froth Column 784 Relating the Flotation Response of Pyrrhotite to the Adsorption of Sodium Carboxymethyl Cellulose and Sodium Isobutyl Xanthate on its Surface in Process Water of a Degrading Quality 87Malibongwe S. Manono, Lisa L. October and Kirsten C. Corin4.1 Introduction 884.2 Experimental Methods 914.3 Results and Discussion 974.4 Conclusions 1075 Simulated Short Cycle Water Recirculation on the Flotation Performance of a UG2 Cu--Ni--PGM Ore 111Malibongwe S. Manono, Michael S. Ngau and Kirsten C. Corin5.1 Introduction 1125.2 Materials and Methods 1155.3 Results and Discussion 1265.4 Conclusions 1376 Complexity of Chalcopyrite Mineral Affecting Copper Recovery During Leaching 145Kolela J. Nyembwe, Frans Waanders, Martin Mkandawire, Bhekie Mamba and Elvis Fosso-Kankeu6.1 Introduction 1466.2 CuFeS2 Crystal Structure 1476.3 Application of Dissolution/Leaching of Chalcopyrite 1486.4 Challenges Associated with Copper Dissolution from the Chalcopyrite Mineral 1496.5 H2SO4-Fe2(SO4)3-FeSO4-H2O Speciation 1536.6 Parameters Affecting Dissolution 1556.7 Thermodynamic Considerations 1606.8 CuFeS2 Phases Conversion/Copper Sulfide (Cu-S) Intermediate Phases 1616.9 Conclusion 1727 Fe3+-Fe2+ Redox Cycle Peculiarity in the Acid Dissolution of Copper--Cobalt Complex Ores 179Bienvenu Mbuya, Léon Zeka and Antoine F. Mulaba-Bafubiandi7.1 Introduction 1807.2 Conventional Leaching of Copper--Cobalt Minerals 1827.3 Fe3+--Fe2+ Redox Cycle in the Dissolution of Mixed Oxidized and Sulfide Minerals 2027.4 Application of Mineral--Mineral Leaching Process to the Dissolution of Complex Ores 2087.5 Conclusion 2128 Rare Earth Elements (REEs) in Complex Ores and Spent Materials: Processing Technologies and Relevance in the Global Energy Transition 217Theophilus Ile Ojonimi, Tina Phiri Chanda, Ilemona C. Okeme, Ferdinand Asuke and Antoine F. Mulaba-Bafubiandi8.1 Introduction 2188.2 The Chemistry of REEs 2208.3 REE Minerals and Deposit Types 2208.4 REE Ore Mining and Processing Technologies 2238.5 Relevance of REEs in Energy Transition 2398.6 Conclusion 241References 241Index 249

Elvis Fosso-Kankeu, PhD, is a professor in the Department of Metallurgy, Faculty of Engineering and Built Environment, University of Johannesburg, Doornfontein, South Africa. His research focuses on the hydrometallurgical extraction of metal from solid phases, the prediction of pollutant dispersion from industrial areas, and the development of effective and sustainable methods for the removal of inorganic and organic pollutants from polluted water. He has published more than 220 papers including journal articles, books, book chapters, and conference proceedings papers. He has won several research awards including the NSTF Award (National Science and Technology Forum: largest science, engineering, technology, and innovation awards in South Africa and are known as the “Science Oscars” of recent times) Engineering Research Capacity Development, in 2019.Bhekie B. Mamba, PhD, is the executive dean of the College of Science, Engineering, and Technology, the University of South Africa. Prof Mamba is a visionary and has occupied several leadership positions including being a Professor and Head at the Department of Applied Chemistry at the University of Johannesburg, and the Director of the Institute of Nanotechnology and Water Research at the University of Johannesburg. He has published about seven book chapters, over 250 journal articles, about 12 technical reports, and over 50 papers in conference proceedings. His general research interest involves developing advanced technologies for water treatment, which include nanotechnology and membrane technology.Antoine F. Mulaba-Bafubiandi is emeritus professor at the University of Johannesburg, South Africa. He is the first Head of School of Mining, Metallurgy and Chemical Engineering, Faculty of Engineering and The Built Environment, and the founding chair of the Mineral Processing and Technology Research Center (MPTRC). One of his current research projects involves the use of biomass for the extraction of gold (via hydrometallurgy) and the reduction of ferromanganese ores (via pyrometallurgy).

• Preface xiii1 Optimization of the Mechanical Comminution -- The Crushing Stage 1Ngonidzashe Chimwani1.1 Introduction 21.2 The Role of Crushers 51.3 Conclusion 312 Challenges Related to the Flotation Process of Complex Phosphate Ores 41Nheta Willie and Hlahane Morake D.2.1 Introduction to the Geology of Complex Phosphate Ores 422.2 Phosphate Rock Beneficiation Processes 442.3 Froth Flotation of Sedimentary Phosphate Ore 482.4 Challenges Facing Flotation of Phosphate Rock 542.5 Future Research Directions 582.6 Conclusion 583 Increasing Ionic Strength and Oxyhydroxo Species in Process Water on the Floatability of Chalcopyrite and Pentlandite for a Selected Cu--Ni Bearing Ore Flotation 65Malibongwe S. Manono, Katlego M. Matibidi, Lisa L. October, Catherine K. Thubakgale and Kirsten C. Corin3.1 Introduction 663.2 Materials and Methods 693.3 Results and Discussion 723.4 Froth Column Studies from a Two-Froth Column 784 Relating the Flotation Response of Pyrrhotite to the Adsorption of Sodium Carboxymethyl Cellulose and Sodium Isobutyl Xanthate on its Surface in Process Water of a Degrading Quality 87Malibongwe S. Manono, Lisa L. October and Kirsten C. Corin4.1 Introduction 884.2 Experimental Methods 914.3 Results and Discussion 974.4 Conclusions 1075 Simulated Short Cycle Water Recirculation on the Flotation Performance of a UG2 Cu--Ni--PGM Ore 111Malibongwe S. Manono, Michael S. Ngau and Kirsten C. Corin5.1 Introduction 1125.2 Materials and Methods 1155.3 Results and Discussion 1265.4 Conclusions 1376 Complexity of Chalcopyrite Mineral Affecting Copper Recovery During Leaching 145Kolela J. Nyembwe, Frans Waanders, Martin Mkandawire, Bhekie Mamba and Elvis Fosso-Kankeu6.1 Introduction 1466.2 CuFeS2 Crystal Structure 1476.3 Application of Dissolution/Leaching of Chalcopyrite 1486.4 Challenges Associated with Copper Dissolution from the Chalcopyrite Mineral 1496.5 H2SO4-Fe2(SO4)3-FeSO4-H2O Speciation 1536.6 Parameters Affecting Dissolution 1556.7 Thermodynamic Considerations 1606.8 CuFeS2 Phases Conversion/Copper Sulfide (Cu-S) Intermediate Phases 1616.9 Conclusion 1727 Fe3+-Fe2+ Redox Cycle Peculiarity in the Acid Dissolution of Copper--Cobalt Complex Ores 179Bienvenu Mbuya, Léon Zeka and Antoine F. Mulaba-Bafubiandi7.1 Introduction 1807.2 Conventional Leaching of Copper--Cobalt Minerals 1827.3 Fe3+--Fe2+ Redox Cycle in the Dissolution of Mixed Oxidized and Sulfide Minerals 2027.4 Application of Mineral--Mineral Leaching Process to the Dissolution of Complex Ores 2087.5 Conclusion 2128 Rare Earth Elements (REEs) in Complex Ores and Spent Materials: Processing Technologies and Relevance in the Global Energy Transition 217Theophilus Ile Ojonimi, Tina Phiri Chanda, Ilemona C. Okeme, Ferdinand Asuke and Antoine F. Mulaba-Bafubiandi8.1 Introduction 2188.2 The Chemistry of REEs 2208.3 REE Minerals and Deposit Types 2208.4 REE Ore Mining and Processing Technologies 2238.5 Relevance of REEs in Energy Transition 2398.6 Conclusion 241References 241Index 249