Preface...xix. CHAPTER 1 Overview CHAPTER 2 Rare Earth Production, Use and Price... 15

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2 Contents Preface...xix CHAPTER 1 Overview Exploited Properties Uses Occurrence Mines and Mining Rare Earth [RE] Extraction Metal Production Rare Earth Uses Rare earth metals in magnet alloys Rare earths in rechargeable battery electrodes Rare earth automobile exhaust pollution abatement catalysts Glass polishing powders Luminescent and phosphorescent uses Rare Earth Recycling Summary...12 References...13 Suggested Reading...14 CHAPTER 2 Rare Earth Production, Use and Price Chapter Objectives Form of Use Detailed Uses Rare Earth Prices Comparison with platinum group metals Mining Rare Earths Locations Summary...29 References...29 CHAPTER 3 Mining and Rare Earth Concentrate Production Rare Earth Deposits Igneous Deposits Mining Extracting Rare Earth Elements from Mined Ore...32 v

3 vi Contents 3.5 Concentrate Production Froth Flotation Flotation Product Flotation summary Rare Earth Beach Sands Rare Earth Cation Adsorption Clays Deposit Structure Ion Adsorption Clay Formation Commercial Leaching of the Clays Initial Rare Earth Oxide Production Summary...44 References...45 Suggested Reading...46 CHAPTER 4 Extracting Rare Earth Elements from Concentrates Industrial Rare Earth Minerals Industrial Rare Earth Extraction Extraction from Monazite and Xenotime Ores Caustic soda leaching Advantages of caustic soda leaching Acid baking process Bastnasite Leaching Roast-hydrochloric acid leach process Caustic soda leaching Sulfuric acid baking Rare Earth Cation Adsorption Clays Leaching methods Loparite Apatite Sulfuric acid leaching Nitric acid leaching New Processes for Other Rare Earth Minerals Including Silicates Thor Lake, Northwest territories, Canada Dubbo, New South Wales, Australia The Key Question of Radioactive Impurities Removal The radioactive families Thorium and uranium removal Radium removal...65

4 Contents vii Lead removal Actinium removal Thorex radioactive element removal process Summary...67 Suggested Reading...67 CHAPTER 5 Rare Earths Purification, Separation, Precipitation and Calcination Selective Crystallization Ion Exchange Solvent Extraction Solvent extraction process how to get pure rare earths from a mixed rare earth solution The industrial solvent extraction equipment mixersettlers The chemistry of solvent extraction and the solvent choice Chloride process vs. nitrate process Pure Rare Earth Compound Production Oxides production Phosphates production Fluorides Summary...87 Appendix 5.1 Rare Earth Separation Simulation...88 Appendix 5.2 Rare Earth Separations Using Specific Oxidation Degrees...88 Appendix Cerium purification using Ce(IV) oxidation degree...88 Appendix Europium purification using Eu(II) oxidation degree...89 Appendix 5.3 Chemical Reagents Consumption...89 Appendix Solvation...90 Appendix Anion Exchange...90 Appendix Cation Exchange...91 Reference...91 CHAPTER 6 Production of Rare Earth Metals and Alloys Electrowinning Reduction Electrowinning Industrial reduction...94

5 viii Contents 6.2 Industrial Rare Earth Electrowinning Chloride Electrowinning Reactions Metal purity Alloy electrowinning Industrial status Oxide Feed Fluoride Molten Salt Electrowinning Electrolytic cell Electrolyte Reactions Neodymium-iron alloy production Purity Neodymium Electrodeposition Rate Electrodeposition rate Metals and alloys made industrially by electrowinning Summary References Suggested Reading CHAPTER 7 Metallothermic Rare Earth Metal Reduction Samarium Reduction Thermodynamic Explanation Lanthanum and tantalum vapor pressures Reduction of Rare Earth Fluorides with Calcium Metal Operation Thermodynamic Explanation Interpretation Refining Rare Earth Metals and Alloys Vacuum Casting Lanthanum Vaporization/Vapor Deposition Summary References Suggested Reading CHAPTER 8 Rare Earth Electronic Structures and Trends in Properties Electronic Configuration of Rare Earths Rare earths in the periodic table Electronic configurations of rare earth elements Focus on 4f energy levels...126

6 Contents ix 8.2 Degrees of Oxidation of Rare Earths The metallic state The ionic state Lanthanides in Solution (in Water) Common Rare Earth Oxides Non-stoichiometric oxides Yttrium aluminum garnet: YAG Phosphate RE: LnPO Summary CHAPTER 9 Rare Earth Catalysts Chapter Objectives Automotive Catalytic Conversion Platinum group metals versus rare earth oxides Principal role The Automotive Catalytic Converter Converter internal structure Catalyst support platform Channel wall requirements Catalyst Deposition Dispersion preparation Dispersion application Drying and heat treatment Critical steps Catalyst layer arrangements Automotive Catalysts: Past, Present, and Future Catalytic Reactions CO(g) Oxidation Without Catalyst (Minimal) Gas-gas oxidation kinetics Early Catalytic Converter Objectives Gaseous Hydrocarbon Oxidation Cold Start-up Nitrogen Oxide (NO x (g)) Reduction Required gas composition Engine air-fuel ratio control Optimum ceria-zirconia composition Optimum platinum group metal use Diesel Engine Pollution Abatement Systems Example soot elimination process Tailpipe emission...158

7 x Contents 9.13 Catalytic Petroleum Cracking Cracking process The catalyst La and Ce in catalyst Quantitative Benefits Explanation Hydrothermal stability Neodymium Catalysts Samarium Catalysts Summary References Suggested Reading Appendix 9.1 Tailpipe Gas Composition Control CHAPTER 10 Rare Earths in Rechargeable Batteries Chapter Objectives Advantages and Disadvantages of Ni-MH Batteries Ni-MH Battery Operation Initial charging Discharging (Use) Recharging Toyota Prius recharging Ni-MH Battery Components Nickel Hydroxide Electrode Alloy (Hydrogen Storage) Electrode Charging side effects at the alloy electrode Alloy choice Recycling Appraisal Summary References Suggested Reading CHAPTER 11 Rare Earths in Alloys and Metals Chapter Objectives Cast Iron Ductile Cast Iron Industrial Procedures Rare Earth Benefits Ductile Iron Summary Rare earth metal additions to molten steel...185

8 Contents xi 11.7 Rare Earth-Magnesium Alloys Rare earth-magnesium microalloying Rare Earth Alloys with Other Metals Summary References Suggested Reading CHAPTER 12 Polishing with Rare Earth Oxides Mainly Cerium Oxide CeO Introduction, Contents of the Chapter Production of Polishing Compounds Classical polishing powder (glass applications) Semiconductor polishing slurries The Polishing Process The type of glass to be polished The type of slurry system Type of polishing machine/pad being used and glass surface quality Industrial Cerium Oxide Polishing Polishing efficiency Glass industry what kind of glasses to polish? No polishing needed Polishing needed Electronic industry: fine polishing is needed Leading Producers of Rare Earth Polishing Powders China Japan Europe USA Trivalent Ce 3þ and Tetravalent Ce 4þ Chemistry Behavior of Ce 3þ and Ce 4þ in aqueous solution CeþIII and CeþIV ions in solution Inorganic condensation to CeO Crystal chemistry of cerium oxides Two additional remarks A Process to Prepare CeO 2 Particles Synthesis of (sub-) micronic ceria powders Synthesis of micronic Ceria colloidal nanoparticles Chemical or Mechanical? The CMP Process Introduction Choice of ceria: the Cook model Description of the mechanism...208

9 xii Contents 12.9 Summary References Suggested Reading CHAPTER 13 Permanent Magnets Based on Rare Earths: Fundamentals Introduction What Can Be Expected from the Pure RE Metals? About Ferromagnetism Hysteresis loop-first quadrant-magnetization curve-remanence Second quadrant-demagnetization-coercitivity Hysteresis loop-maximum energy product BH max Precision on the units Dependence of magnetization on temperature Requirements for exceptional magnets Alloying RE Metals and TM: A Breakthrough in the World of Permanent Magnets The Sm/Co magnets Nd/Fe/B magnets Magneto-Crystalline Anisotropy, the Key to the Exceptional Properties Qualification, Codification of the RE Magnets What are the changes of the performances with temperature? How to improve the temperature dependence of the Nd-based magnet? Codification of the magnets Summary Suggested Reading CHAPTER 14 Rare Earth-Based Permanent Magnets Preparation and Uses Introduction The Superiority of the RE Magnets Some Limitations of RE Magnets and Current Remedial Strategies Direct substitution of Dy in Nd-Fe-B alloys Substitution of Dy and Tb by grain boundaries diffusion method...234

10 Contents xiii 14.4 Preparation of RE Magnets by Powder Metallurgy Production of neodymium-iron and dysprosium-iron alloys Production of samarium metal Heating and casting the RE alloys Preparation of fine particles Compaction of the fine particles and magnetic alignment Sintering at high temperature and pulse magnetization Some Practical Information Concerning NdFeB Magnets Shaping and surface protection by coating Magnetic orientation Bonded magnets, packaging, and safety issues Applications of RE Magnets Applications related to attractive magnetic forces Applications related to power generation Applications related to electrical motors Application related to transducers and sound production Application related to medical applications and imaging Summary Suggested Reading CHAPTER 15 Introduction to Rare Earth Luminescent Materials Basics of Luminescence Phenomena Introduction to the luminescence Luminescence characteristics (emission and absorption spectra, efficiency, and decay time) Rare earth luminescent materials definition Luminescence of Rare Earths Electronic configuration of rare earths Electronic transitions in rare earth-based phosphor materials (4f-4f, 4f-5d, and CT) Focus on 4f-4f transitions (intraconfigurational transitions) Focus on 4f-5d transitions (interconfigurational transitions) Focus on the charge transfer transitions (interconfigurational transition) Summary...261

11 xiv Contents 15.3 The Most Classical Rare Earth-doped Luminescent Materials Eu 3þ, the most common red emitter Tb 3þ, the most common green emitter Eu 2þ, the most common blue emitter Ce 3þ, a versatile candidate for phosphor materials Yb 3þ and Er 3þ, a perfect couple for up-conversion Other cases Rare Earth Luminescent Materials: Synthesis Routes Requirements for a good phosphor material The traditional solid-state route The Precursor route Appendix f Energy Levels of Rare Earths Appendix d Energy Levels of Rare Earths (the Crystal Field Theory) Appendix 15.3 Transition Selection Rules References Suggested Reading CHAPTER 16 Applications of Rare Earth Luminescent Materials Rare Earth for Lighting Application Lighting devices, an overview Focus on trichromatic fluorescent lamps (fluorescent tubes, and CFL) Focus on LED and the phosphors Last evolution of the lighting market Rare Earths for Display Application Cathode Ray Tube (CRT), the use of electron beam for early color TV PDP (Plasma display panels), high photonic excitation The LCD display and their backlighting (CCFL and LED backlights) Last evolution of the display market Rare Earth for Medical Equipments Focus on x-ray intensifying screens Focus on photostimulated storage phosphor screen Focus on tomography medical equipment: X-ray CT and PET...307

12 Contents xv 16.4 Other Rare Earth Applications Gadolinium as contrast agent for NMR (not luminescent properties) Afterglow pigment Rare earth for anti counteracting marking & tagging Suggested Reading Annex 16.1 Basics of Colorimetry The human eye The trichromatic color diagram CHAPTER 17 Rare Earth Doped Lasers and Optical Amplifiers Gain Media Stimulated emission Population inversion Optical Amplifiers Erbium doped fiber amplifier (EDFA) How an optical amplifier works Light Amplification by Stimulated Emission of Radiation Definition of laser How a laser works The Rare Earth Candidates for Laser Emission Rare earth doped crystals Rare earth doped glasses Rare earth doped transparent ceramics Laser Applications Material processing, manufacturing Medical applications Summary References CHAPTER 18 Rare Earth Recycle Extent of Rare Earth Recycle Reasons for this miniscule rare earth recycle extent Twenty-first Century Rare Earth Recycle Increase Nickel-Metalhydride Rechargeable Battery Recycle Industrial Recycle Smelting Recycle Furnace Slag Requirements Avoiding glassiness after granulation Recovery of Rare Earths from Slag Recovery of Ni and Co from the Recycle Furnace Product Alloy...340

13 xvi Contents 18.8 Offgas Treatment Summary of Rare Earth Battery Recycle Recovering Rare Earths from End-of-use Fluorescent Lamps Phosphors and their Compositions Recycle objective The Recycle Process Recovery of phosphor powder from end-of-use fluorescent lamps Rare earth oxide production Rare earth phosphate production Rare Earth Magnet Recycle End-of-use magnet recycle Suggested End-of-Use Rare Earth Magnet Recycle Method In between Ceria Polishing Powder Recycle Fluid Catalytic [Petroleum] Cracking Catalyst Recycle Automobile Emission Reduction Catalyst Recycle Current Recycle Activity Summary References Suggested Reading CHAPTER 19 Epilogue World Events Consequences Recycling Thrifting Substitition Smuggler Responses Government Responses to Rare Earth Shortages Manufacturing Industry Responses Mining/Production Industry Response Summary Predictions References Further Reading Index Color Plate Section