Rare Earth Elements E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Serie: Special Publications
• Sprache: Englisch

Seitenzahl: 675

Veröffentlichungsjahr: 2024

Beschreibung

Rare Earth Elements
Sustainable Recovery, Processing, and Purification

Rare earth elements are used in many modern technologies including electronics, clean energy, defense, aerospace, and automotive. It is important that increasing demand is met in ways that are more environmentally, socially, and economically sustainable than in the past.

Rare Earth Elements: Sustainable Recovery, Processing, and Purification describes sources of rare earths and methods of production that have the potential to make recovery, processing, and purification more sustainable.

Volume highlights include:

• Global overview of rare earth production, reserves, and resources
• Improvements in the recovery process to reduce costs and environmental impacts
• Potential new sources of rare earths that were not previously technically feasible
• Options for recovery of rare earths as byproducts of other activities
• Contributions from experts in academia, industry, government, research, and nonprofit organizations

The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.

Leseprobe

Table of Contents

COVER

TABLE OF CONTENTS

TITLE PAGE

COPYRIGHT PAGE

LIST OF CONTRIBUTORS

PREFACE

LIST OF ACRONYMS AND ABBREVIATIONS

1 RARE EARTH INDUSTRY OVERVIEW

1.1. Introduction

1.2. Production

1.3. Trade

1.4. Prices

References

2 RARE EARTH ELEMENTS IN COAL FLY ASH AND THEIR POTENTIAL RECOVERY

2.1. Introduction

2.2. Geochemical Characterization of Fly Ash

2.3. Extractions and Separations for REE Recovery from Fly Ash

2.4. Outlook and Research Needs

Acknowledgments

References

3 RECOVERING OF RARE EARTH ELEMENTS FROM UNCONVENTIONAL RESOURCES: BAUXITE RESIDUE

3.1. Bauxite Residue

Acknowledgments

References

4 RARE EARTHS IN PHOSPHATE: CHARACTERIZATION AND EXTRACTION

4.1. Introduction

4.2. Part I: Chemical and Physical Characterizations of Phosphate‐Processing Streams

4.3. Part II: Detailed Process‐Mineralogy Studies of Amine Flotation Tails

4.4. Part III: Isolation and Characterization of Rare Earth Mineral Particles in Florida Phosphate Rock by DE Rapid Scan Radiography and HRXMT

4.5. Part IV: Process Development on the Concentration of REE‐containing Materials and Extraction of REEs

4.6. Summary

Acknowledgments

References

5 SOLVENT EXTRACTION OF RARE EARTH ELEMENTS FROM AQUEOUS SOLUTIONS

5.1. Solvent Extraction Basics

5.2. Challenges of Alternative Rare Earth Sources

5.3. Testing and Design of Solvent Extraction Circuits

5.4. Case Study—Rare Earth Recovery from Fly Ash

5.5. Future of Solvent Extraction

Acknowledgments

References

6 SEPARATION OF RARE EARTH ELEMENTS BY CRYSTALLIZATION

6.1. Industrial Applications

6.2. Fundamentals of Crystallization

6.3. Solubility Trends of Rare Earth Elements

6.4. Crystallization of Rare Earth Elements

6.5. Precipitation by Reagent Addition

6.6. Redox Precipitation

6.7. Antisolvent Crystallization

6.8. Crystallization by Temperature Modification or Evaporation

6.9. Conclusions

Acknowledgments

References

7 AQUEOUS ELECTROCHEMICAL PROCESSING OF RARE EARTH ELEMENTS

7.1. Introduction

7.2. Redox‐Based Processing

7.3. Liquid‐Metal Cathode Studies

7.4. Electrochemistry‐Driven REE Magnet Dissolution and Recovery

7.5. Perspective and Conclusion

Acknowledgments

References

8 BENEFICIATION OF RARE EARTH ELEMENTS: PROSPECTS FOR BIOTECHNOLOGY DEPLOYMENT

8.1. Introduction

8.2. Technical Constraints for Bioleaching of REE‐Containing Feedstocks

8.3. Technical Considerations for Bioseparation

8.4. General Techno‐Economics of Biorecovery

8.5. Conclusions and Directions for Future Research

Acknowledgments

References

9 ADSORPTION‐BASED SEPARATION AND RECOVERY OF RARE EARTH ELEMENTS

9.1. Introduction

9.2. Surface Functional Groups or Ligands

9.3. Ion‐Exchange Resins

9.4. Inorganic Adsorbents

9.5. Extractant Immobilized Materials

9.6. Surface‐Functionalized Adsorbents

9.7. Molecular‐/Ion‐Imprinted Polymers

9.8. Elution Solutions

9.9. Application to Real Samples

9.10. Synopsis

Acknowledgments

Appendix A. Abbreviations

References

INDEX

END USER LICENSE AGREEMENT

List of Tables

Chapter 2

Table 2.1 Rare earth elements in coal fly ash that could be analyzed for bu...

Chapter 3

Table 3.1 Concentrations of scandium in different bauxite residues.

Table 3.2 Comparison of direct BR leaching methods.

Chapter 4

Table 4.1 Lanthanide content in selected phosphate rock.

Table 4.2 Routine chemical analysis of head samples (wt%).

Table 4.3 Radioactivity analysis of head samples (pCi/g).

Table 4.4 Analysis of REEs, thorium, and uranium in head samples (ppm).

Table 4.5 Size distribution of rare earths in PG.

Table 4.6 Size distribution of major chemical components in PG.

Table 4.7 Total REE concentrations (ppm) in plant A samples.

Table 4.8 Sizing analysis of rougher and cleaner tails from plant A.

Table 4.9 Plant mass flow rates (ton/hour) for plant A.

Table 4.10 Total REE concentrations (ppm) in samples from plant B.

Table 4.11 Sizing analysis of rougher and cleaner tails from plant B.

Table 4.12 Plant B mass distribution (tons).

Table 4.13 Chemical compositions (wt%) of the amine flotation tails.

Table 4.14 Analysis (ppm) of rare earth elements in the amine tails.

Table 4.15 Chemical compositions (wt%) of jigging products from the amine t...

Table 4.17 Analysis (ppm) of U and REEs in the jigging products from the am...

Table 4.18 Size distribution of the amine tails head sample.

Table 4.19 Quantitative mineral analysis of amine tails using MLA.

Table 4.20 Size distribution analysis for the major minerals in amine tails...

Table 4.21 Chemical components of monazite analyzed using EDS.

Table 4.22 Chemical components of xenotime analyzed using EDS.

Table 4.23 Chemical components of zircon analyzed using EDS.

Table 4.24 Chemical components of rutile analyzed using EDS.

Table 4.26 Chemical components of leucoxene analyzed using EDS.

Table 4.27 Chemical components of phosphate analyzed using EDS.*

Table 4.28 Mineralogical composition of a clay sample.

Table 4.29 Chemical analysis of acid plant feed.

Table 4.30 Provided estimated chemical analysis of shaking table concentrat...

Table 4.31 Detailed information for main minerals in Cu–Mo flotation tailin...

Table 4.32 Number of sections with potential rare earth particles on each s...

Table 4.33 Final monazite count per sample.

Table 4.34 Results of one‐stage shaking table separation of amine tails.

Table 4.35 Results from flotation of shaking table separation concentrate....

Table 4.36 REE distribution in cyclone classification products using a 4‐in...

Table 4.37 First‐stage separation of phosphate clay—two duplicate tests.

Table 4.38 Second‐stage separation of phosphate clay—two duplicate tests.

Table 4.39 XRD analysis of cyclone products using the 2‐inch cyclone.

Chapter 5

Table 5.1 Solvent extraction range‐finding tests.

Table 5.2 Percentage of extracted iron after addition of different reducing...

Table 5.3 Percentage stripped of REEs and iron during REE stripping step at...

Table 5.4 Percentage stripped of some heavy metals during the extractant re...

Table 5.5 Extraction results for 15% Cyanex 572 and 13.2%:12% Cyanex 572:TB...

Table 5.6 Factors and levels investigated in the REE extraction tests.

Table 5.7 REE extraction experimental design, based on a Box–Behnken design...

Table 5.8 Results obtained from the extraction design of experiments (singl...

Table 5.9 Summary of the REE recovery response model (second‐order model) f...

Table 5.10 Summary of the REE purity response model (second‐order model) fo...

Table 5.11 Optimized factors for one‐stage REE extraction, equilibrium pH (...

Table 5.12 Results obtained from the lower‐pH REE stripping design of exper...

Table 5.13 Summary of the REE purity response model (second‐order model) fo...

Table 5.14 Results obtained from the higher‐pH REE stripping design of expe...

Table 5.15 Summary of the REE purity response model (second‐order model) fo...

Chapter 7

Table 7.1 Percentage extraction of rare earth elements by Li, Na, and K ama...

Table 7.2 Property comparison between Ga and Ga‐alloys and Hg.

Table 7.3 Half‐wave potential of various rare earth elements, including Li,...

Chapter 9

Table 9.1 Some adsorbents with high adsorption capacity (

q

m

> 350 mg/g) for...

List of Illustrations

Chapter 1

Figure 1.1 Global estimated rare earth mine production (metric tons (Mt) of ...

Figure 1.2 China’s imports of rare earth mineral concentrates by country of ...

Figure 1.3 Malaysia’s imports of rare earth metals from Australia (metric to...

Figure 1.4 Global importers of rare earth compounds (metric tons, gross weig...

Figure 1.5 Global importers of rare earth metals.

Figure 1.6 Cerium and lanthanum oxide prices in U.S. dollars per kilogram (F...

Figure 1.7 Neodymium and praseodymium oxide prices in U.S. dollars per kilog...

Figure 1.8 Samarium and gadolinium oxide prices in U.S. dollars per kilogram...

Figure 1.9 Europium oxide prices in U.S. dollars per kilogram (FOB China)....

Figure 1.10 Dysprosium and terbium oxide prices in U.S. dollars per kilogram...

Figure 1.11 Holmium and erbium oxide prices in U.S. dollars per kilogram (FO...

Figure 1.12 Ytterbium oxide prices in U.S. dollars per kilogram (FOB China)....

Figure 1.13 Lutetium oxide prices in U.S. dollars per kilogram (FOB China)....

Figure 1.14 Yttrium oxide prices in U.S. dollars per kilogram (FOB China)....

Chapter 2

Figure 2.1 Plots showing how REE data are represented, including distributio...

Figure 2.2 Coal‐derived carbons from the combustion of eastern U.S. bitumino...

Figure 2.3 Glassy fly ash particles from the combustion of eastern U.S. bitu...

Figure 2.4 Spinel minerals from the combustion of eastern U.S. bituminous co...

Figure 2.5 Stoker combustion ash from the burning of eastern U.S. bituminous...

Figure 2.6 (a) Monazite (m) with glassy particles in an eastern U.S. bitumin...

Figure 2.7 Chondrite‐normalized plot of SHRIMP‐RG results for constituents o...

Figure 2.8 (a) Mixed monazite (mz) and kaolinite (k) grain in Fire Clay coal...

Figure 2.9 Monazite with included xenotime in the fly ash from the combustio...

Figure 2.10 (a)–(d) Ce‐phosphate on mullite in stoker ash from the combustio...

Figure 2.11 (a) and (b) Opposing sides and different sizes of the FIB lift‐o...

Figure 2.12 (a) TEM image of Fe‐spinel minerals (sp) in fly ash from the com...

Figure 2.13 (a) TEM image of spinel (sp) surrounded by carbon. The area scan...

Figure 2.14 High‐resolution TEM image (a) of Al‐Si glass sphere surrounded b...

Figure 2.15 High‐resolution TEM image (upper left) of Al‐Si glass sphere sur...

Figure 2.16 EELS imaging indicating the presence of Ce associated with needl...

Figure 2.17 Example sequence of unit processes for the recovery and separati...

Figure 2.18 (a)–(f) Scanning electron micrograph with energy dispersive x‐ra...

Chapter 3

Figure 3.1 Leaching process with concentrated HCl developed by Orbite Techno...

Figure 3.2 Bauxite residue leaching process flowsheet (top) and bench scale ...

Figure 3.3 Sc pilot production at Rusal facilities

Figure 3.4 Main methods for major metals & REE extraction from BR by combini...

Chapter 4

Figure 4.1 Logos for CMI team members, February 2020.

Figure 4.2 Flow sheet of phosphate mining and processing in central Florida,...

Figure 4.3 Particle size distribution of phosphate clay sample from FC.

Figure 4.4 Particle size distribution of phosphate clay sample from SFM.

Figure 4.5 Scanning electron microscope‐backscattered electrons (SEM‐BSE) ma...

Figure 4.6 SEM‐BSE image showing monazite inclusion in quartz.

Figure 4.7 SEM‐BSE image showing xenotime monomer.

Figure 4.8 SEM‐BSE image showing xenotime inclusion in quartz.

Figure 4.9 SEM‐BSE image showing zircon monomer.

Figure 4.10 SEM‐BSE image showing rutile and pseudo‐rutile monomers.

Figure 4.11 SEM‐BSE image showing wrapping of quartz by phosphate.

Figure 4.12 XRD peaks of phosphoric acid sludge solids.

Figure 4.13 Radiographs of the pure reference minerals and minerals in Cu–Mo...

Figure 4.14 Comparison between calculated and actual effective atomic number...

Figure 4.15 Mineral attenuation coefficients estimated using XMuDat.

Figure 4.16 Scaled CT number distribution map for mineral phases.

Figure 4.17 (a) Bastnasite radiograph and (b) resulting threshold image used...

Figure 4.18 DE scans, relative reflex, and threshold image of a section from...

Figure 4.20 DE scans, relative reflex, and threshold image of a section from...

Figure 4.21 Sample preparation setup for HRXMT scanning.

Figure 4.22 Final HRXMT samples for each (a) shaking table concentrate, (b) ...

Figure 4.23 Projection images from (a) shaking table concentrate, (b) acid p...

Figure 4.24 2D slice from (a) shaking table concentrate, (b) acid plant feed...

Figure 4.25 3D reconstruction of (a) shaking table concentrate, (b) acid pla...

Figure 4.26 Shaking table concentrate 3D reconstruction by mineral compositi...

Figure 4.28 Phosphogypsum 3D reconstruction by mineral composition.

Figure 4.29 Monazite in 3D reconstruction of shaking table concentrate separ...

Figure 4.30 Monazite in 3D reconstruction of acid plant feed separated appro...

Figure 4.31 Monazite in 3D reconstruction of phosphogypsum separated approxi...

Figure 4.32 A locked particle of acid plant feed found in the size class >10...

Figure 4.33 Conceptual countercurrent leaching flowchart.

Figure 4.34 Settling rate of as‐received phosphoric acid sludge in a graduat...

Figure 4.35 Settling rate of diluted phosphoric acid sludge (30% P

2

O

5

) in a ...

Figure 4.36 Effect of sulfuric acid concentration on leaching recovery.

Figure 4.37 Effect of leaching time on leaching recovery.

Figure 4.38 Effect of phosphoric acid concentration in initial pulp on leach...

Figure 4.39 Proposed approach for REEs, U, and P recovery from phosphate cla...

Figure 4.40 Size distribution of overflow from 2‐inch cyclone testing—mean s...

Figure 4.41 Size distribution of underflow from 2‐inch cyclone testing—mean ...

Figure 4.42 Effect of phosphoric acid concentration in initial pulp on leach...

Chapter 5

Figure 5.1 Mixing of organic and aqueous phases.

Figure 5.2 Separation of organic and aqueous phases.

Figure 5.3 This is a simplified schematic of a SX system using only one stag...

Figure 5.4 Picture of a rag layer formation due to the high concentration of...

Figure 5.5 A simplified schematic of the ion‐exchange mechanism showing in t...

Figure 5.6 These two example McCabe–Thiele diagrams use the same equilibrium...

Figure 5.7 After extraction with 13.2%:12% Cyanex 572:TBP extractant.

Figure 5.9 After extraction with 15% Cyanex 572 extractant.

Figure 5.10 Fitted line plot of the REE recovery response model (second‐orde...

Figure 5.11 Fitted line plot of the REE purity (REEP) response model (second...

Figure 5.12 Fitted line plot of the REE purity (REEP) response model (second...

Figure 5.13 Fitted line plot of the REE purity (REEP) response model (second...

Chapter 6

Figure 6.1 Solubility products, valid at 25 °C and zero ionic strength, for ...

Figure 6.2 Solubility of the most stable hydrated sulfate, chloride, and nit...

Chapter 7

Figure 7.1 Chlor‐alkali process for production of Na metal.

Figure 7.2 Recovery of REEs from dilute solutions. (a) Formation of dark gra...

Figure 7.3 Single‐anode electrolysis reactor for selective extraction of REE...

Figure 7.4 Dual‐anode electrolysis reactor for selective extraction of REEs ...

Figure 7.5 (a) Membrane cell for REEs separation and (b) cross section of me...

Chapter 8

Figure 8.1 Schematic representation of bioleaching (left) and bioseparation ...

Figure 8.2 Surface display of LBT by

E. coli

. Cartoon depicting the Lpp–OmpA...

Figure 8.3 Total REEs leached from FCC catalyst (1.5%, w/w) after 6 weeks wi...

Figure 8.4 Relative distributions of REEs in solid materials (left bar) and ...

Figure 8.5 Calculated and experimental phase behavior and thermodynamic prop...

Figure 8.6 Solubility of neodymium hydroxide as a function of pH at 25 °C in...

Figure 8.7 Calculated speciation for the system studied in Figure 8.1 in the...

Figure 8.8 Total dissolved molality of Nd after equilibrating a coal fly ash...

Figure 8.9 Total dissolved Si concentration predicted by excluding (dashed l...

Figure 8.10 Process for REE recovery based on biosorption and desorption. RE...

Chapter 9

Figure 9.1 Different ligands used for REE adsorption in chelating ion‐exchan...

Figure 9.2 Distribution coefficient (

K

d

) for various adsorbents. The legends...

Figure 9.3 Different bite angles of the ligands grafted onto KIT‐6 (modified...

Figure 9.4 Distribution coefficient (

K

d

) for various adsorbents in actual RE...

Guide

Cover Page

Table Of Contents

Title Page

Copyright Page

List Of Contributors

Preface

List Of Acronyms And Abbreviations

Begin Reading

Index

Wiley End User License Agreement

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Special Publications 79

RARE EARTH ELEMENTS

Sustainable Recovery, Processing, and Purification

Athanasios K. Karamalidis

Roderick Eggert

Editors

This work is a co‐publication of the American Geophysical Union and John Wiley and Sons, Inc.

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Library of Congress Cataloging‐in‐Publication DataNames: Karamalidis, Athanasios K., editor. | Eggert, Roderick G., editor.Title: Rare earth elements : sustainable recovery, processing, and purification / Athanasios K. Karamalidis, Roderick Eggert, editors.Other titles: Rare earth elements (John Wiley & Sons)Description: Hoboken, NJ, USA : Wiley, 2025. | Includes bibliographical references and index.Identifiers: LCCN 2024035432 (print) | LCCN 2024035433 (ebook) | ISBN 9781119515036 (hardback) | ISBN 9781119515067 (adobe pdf) | ISBN 9781119515043 (epub)Subjects: LCSH: Rare earths. | Ore‐dressing. | Strategic materials. | Chemicals–Purification.Classification: LCC TN490.A2 R368 2024 (print) | LCC TN490.A2 (ebook) | DDC 661/.041–dc23/eng/20240813LC record available at https://lccn.loc.gov/2024035432LC ebook record available at https://lccn.loc.gov/2024035433

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LIST OF CONTRIBUTORS

Andre AnderkoCritical Materials Innovation HubOLI Systems Inc.Parsippany, New Jersey, USA

Darwin ArgumedoBrightmark EnergyIllinois Institute of TechnologyFort Wayne, Indiana, USA

Efthymios BalomenosLaboratory of MetallurgyNational Technical University of AthensAthens, Greece

Raquel CrossmanFreeport‐McMoRanPhoenix, Arizona, USA

Gaurav DasCritical Materials Innovation HubOLI Systems Inc.Parsippany, New Jersey, USA

Panagiotis DavrisLaboratory of MetallurgyNational Technical University of AthensAthens, Greece

David DePaoliOak Ridge National LaboratoryOak Ridge, Tennessee, USA

Luis A. DiazCritical Materials Innovation HubIdaho National LaboratoryIdaho Falls, Idaho, USA

Roderick EggertCritical Materials Innovation HubColorado School of MinesGolden, Colorado, USA

Eugene EngmannCritical Materials Innovation HubIdaho National LaboratoryIdaho Falls, Idaho, USAandDepartment of Nuclear Engineering and Industrial ManagementUniversity of IdahoIdaho Falls, Idaho, USA

Ali EslamimaneshCritical Materials Innovation HubOLI Systems Inc.Parsippany, New Jersey, USA

Kerstin ForsbergDepartment of Chemical EngineeringKTH Royal Institute of TechnologyStockholm, Sweden

Yoshiko FujitaCritical Materials Innovation HubIdaho National LaboratoryIdaho Falls, Idaho, USA

Joseph GambogiNational Minerals Information CenterU.S. Geological SurveyReston, Virginia, USA

Michael HeinrichsBattelle Memorial InstituteColumbus, Ohio, USA

James C. HowerCenter for Applied Energy ResearchUniversity of KentuckyLexington, Kentucky, USA

Heileen Hsu‐KimDepartment of Civil & Environmental EngineeringDuke UniversityDurham, North Carolina, USA

Yongqin JiaoCritical Materials Innovation HubLawrence Livermore National LaboratoryLivermore, California, USA

Zhen JinFlorida Industrial and Phosphate Research InstituteFlorida Polytechnic UniversityLakeland, Florida, USA

Athanasios K. KaramalidisDepartment of Energy and Mineral EngineeringPennsylvania State UniversityState College, Pennsylvania, USA

Allan KolkerGeology, Energy & Minerals Science CenterU.S. Geological SurveyReston, Virginia, USA

Margaret LenckaCritical Materials Innovation HubOLI Systems Inc.Parsippany, New Jersey, USA

Haijun LiangFlorida Industrial and Phosphate Research InstituteFlorida Polytechnic UniversityLakeland, Florida, USA

Chen‐Luh LinDepartment of Metallurgical EngineeringUniversity of UtahSalt Lake City, Utah, USA

Tedd E. ListerCritical Materials Innovation HubIdaho National LaboratoryIdaho Falls, Idaho, USA

Jan MillerDepartment of Metallurgical EngineeringUniversity of UtahSalt Lake City, Utah, USA

Dimitrios PaniasLaboratory of MetallurgyNational Technical University of AthensAthens, Greece

Dan ParkCritical Materials Innovation HubLawrence Livermore National LaboratoryLivermore, California, USA

Ioannis PaspaliarisLaboratory of MetallurgyNational Technical University of AthensAthens, Greece

Madhav PatelDepartment of Energy and Mineral EngineeringPennsylvania State UniversityState College, Pennsylvania, USA

Rick PetersonBrightmark EnergySan Francisco, California, USA

Desirée L. PlataDepartment of Civil & Environmental EngineeringMassachusetts Institute of TechnologyCambridge, Massachusetts, USA

David ReedCritical Materials Innovation HubIdaho National LaboratoryIdaho Falls, Idaho, USA

Michael SvärdDepartment of Chemical EngineeringKTH Royal Institute of TechnologyStockholm, Sweden

Vicki ThompsonCritical Materials Innovation HubIdaho National LaboratoryIdaho Falls, Idaho, USA

Patrick ZhangFlorida Industrial and Phosphate Research InstituteFlorida Polytechnic UniversityLakeland, Florida, USA

Haiyan ZhaoDepartment of Chemical and Biological EngineeringUniversity of IdahoMoscow, Idaho, USAandDepartment of Nuclear Engineering and Industrial ManagementUniversity of IdahoIdaho Falls, Idaho, USA

PREFACE

Rare earths are a family of 17 chemical elements—the 15 lanthanides, plus scandium and yttrium. Given their similar chemical characteristics, rare earths are typically found together in nature. These elements can be considered the vitamins and spices of many modern engineering materials. In small quantities, they provide essential properties to permanent magnets in electric motors, phosphors in LED lights, lasers, catalysts, and ceramic pigments, to name but a few important applications.

Demand for rare earths will increase significantly in the coming decades. In part, growth in demand will reflect improvements in living standards as the incidence of poverty falls and as low‐income countries become middle‐income countries and middle‐income countries become high‐income countries. Moreover, much of the growth in demand will reflect structural or systemic changes in economic activity associated with decarbonization and development and deployment of technologies that have lower environmental footprints than current technologies.

Society requires that these increased demands be met in more sustainable ways. Although sustainability means different things to different people, we define recovery, processing, and purification as “sustainable” if this production meets or exceeds society’s requirements for environmental performance, social performance (social sustainability, in the sense that they are done with the support and participation of the local communities in which they occur), and economic performance (delivering sufficient, affordable, and secure supplies of rare earths from the perspective of rare earth users).

This book describes sources of rare earths and methods of production that have the potential to make rare earth recovery, processing, and purification more sustainable. The chapters consider innovations that would enhance environmental and economic performance.

Some chapters focus on improving the process of rare earth recovery—reducing both the costs and environmental impacts of production and increasing the likelihood of both community acceptance and profitable production. These processes include enhanced beneficiation using biotechnology, separations via crystallization and improved solvent extraction, and aqueous electrochemical processing.

Other chapters focus on unlocking new sources of rare earths that are unconventional, secondary, or both. Unconventional means recovering rare earths from sources from which, to date, there has not been technically and commercially feasible production at scale. Secondary means sources from which rare earths would not be recovered as the principal or primary product but rather as a byproduct of other activities. These include coal fly ash, bauxite residues, and various waste streams associated with phosphate rock and phosphoric acid production.

Contributions to this book come from more than 35 authors from 15 different organizations in different parts of the world. They carry out their work at universities, national laboratories, government agencies, institutes, nonprofit organizations, and companies.

The book should be of interest to a range of readers including academic and government researchers, industry professionals over the entire supply chain who rely on rare earths, market analysts, and graduate students.

We are grateful for the support and guidance we have received from many individuals and groups, especially the chapter authors and staff members at AGU and Wiley. We are also thankful for an outstanding set of colleagues, at both universities and other organizations in the United States and internationally, who were willing to take time from their busy schedules to read and provide insightful comments and feedback on different chapters.

Summing up, the book’s purpose is to shine a light on new processes and sources of rare earths that have the potential to enhance the availability of rare earths, allowing all of us to benefit from the special properties rare earths provide to modern technologies.

Athanasios K. Karamalidis

Pennsylvania State University, USA

Roderick Eggert

Colorado School of Mines, USA

LIST OF ACRONYMS AND ABBREVIATIONS

AC

Activated carbon

ADP

Acid digestion process

AEM

Anion exchange membrane

AER

Anion‐exchange resin

APTES

3‐aminopropyl triethoxysilane

APTMS

3‐aminopropyl trimethoxysilane

APTS

3‐[2‐(2‐aminoethylamino) ethylamino] propyl‐trimethoxysilane

ATMP

Amino tris(methylene phosphonic acid)

ATS

Aluminum silicotitanates

BHPA

N‐Benzoyl‐N‐phenylhydroxylamine

BPG

Bis(phosphonomethyl) glycine

BR

Bauxite residue

CBMM

Companhia Brasileira de Metalurgia e Mineração

CER

Cation‐exchange resin

CMI

Critical Materials Innovation (Hub)

CN

Coordination number

CNT

Carbon nanotube

COK

Centre for Research Chemistry and Catalysis

COMEX

Commodity Exchange

CT

Computed tomography

Cyanex 272

Bis(2,4,4‐trimethylpentyl) phosphinic acid

DEHPA

Di(2‐ethylhexyl) phosphoric acid

DETA

Diethylenetriamine

DGA

Diglycolamide

DMF

N,N‐dimethylformamide

DOE

United States Department of Energy

DOODA

3,6‐dioxaoctanediamidopropyl

DSP

Desilication product

DTPA

Diethylenetriaminepentaacetic acid

DTPADA

Diethylenetriaminepentaacetic dianhydride

EAF

Electric arc furnace

EDTA

Ethylenediaminetetraacetic acid

EELS

Electron energy‐loss spectroscopy

EPA

Environmental Protection Agency

EXAFS

Extended X‐ray absorption fine structure

FCC

Fluid catalytic cracking

FDGA

Furan‐2,4‐ diamidopropyltriethoxysilane

FIB

Focused ion beam

FIPR

Florida Industrial and Phosphate Research (Institute)

GO

Graphene oxide

GONS

Graphene oxide nanosheet

HDEHP

Bis(2‐ethylhexyl) hydrogen phosphate

HER

Hydrogen evolution reaction

HMS

Heavy‐mineral sands

HREE

Heavy rare earth element

HRXMT

High‐resolution X‐ray microtomography

HS

Harmonized system

HTS

Harmonized tariff schedule

ICP‐AES

Inductively coupled plasma atomic emission spectroscopy

ICP‐MS

Inductively coupled plasma mass spectroscopy

ICP‐OES

Inductively coupled plasma optical emission spectroscopy

IER

Ion‐exchange resin

IIP

Ion‐imprinted polymer

IL

Ionic liquids

IUPAC

International Union of Pure and Applied Chemistry

KAIST

Korean Advanced Institute of Science and Technology

KMt

Kilo metric tons

LA‐ICP‐MS

Laser‐ablation ‐ inductively coupled plasma ‐ mass spectroscopy

LBT

Lanthanide‐binding tag

LMC

Liquid‐metal cathode

LME

London Metal Exchange

LREE

Light rare earth element

MCM

Mobil Composition of Matter

MIP

Molecular imprinted polymer

MISA

Moscow Institute of Steel and Alloys

MLR

Ministry of Land and Resources (China)

MMt

Million metric tons

MOF

Metal‐organic framework

MRC

Metallothermic reduction and comproportionation

MSE

Molten salt electrolysis

MWh

Megawatt hour

NIST

National Institute of Standards and Technology

ORNL

Oak Ridge National Laboratory

ORP

Oxidation‐reduction potential

PCC

Pulverized coal combustion

PEGDA

Polyethylene glycol diacrylate

QC

Quality control

REE

Rare earth elements

REO

Rare earth oxides

REY

Rare earth elements + Yttrium

SAED

Selected area electron diffraction

SAIL

Steel Authority of India Limited

SEM‐EDS

Scanning electron micrography energy dispersive x‐ray spectroscopy

SEM‐EDX

Scanning electron micrography energy dispersive x‐ray spectroscopy

SX

Solvent extraction

TBP

Tributyl phosphate

TEA

Techno‐Economic Analysis

TEM

Transmission electron microscopy

TOPO

Trioctylphosphine oxide

TREO

Total rare earth oxides

UCC

Upper continental crust

USBM

United States Bureau of Mines

USGS

United States Geological Survey

XANES

X‐ray absorption near‐edge structure

XRD

X‐ray diffraction

μXRF

Microprobe X‐ray fluorescence spectroscopy

1RARE EARTH INDUSTRY OVERVIEW

Joseph Gambogi

National Minerals Information Center, U.S. Geological Survey, Reston, Virginia, USA

Abstract

The rare earth elements (REEs) are a group of moderately abundant elements comprising the 15 lanthanides, scandium (Sc), and yttrium (Y). Most REE production has been from deposits where specific minerals (usually bastnaesite, loparite, monazite, and xenotime) or ores such as ion‐adsorption clays are amenable to known industrial‐scale physical and chemical separation techniques. The rare earth industry is complex and evolving with changing geographic sources of supply and shifting demand for specific REEs. Global mine production tripled from 2010 to 2022. New sources of supply have changed trade patterns for mineral concentrates, metals, and compounds. While China has remained the largest global producer, its imports have increased from 12 thousand metric tons (KMt) in 2010 to over 126 KMt in 2021. A few mine producers have emerged as established sources of supply, and interests in developing new alternative sources of supply are ongoing. Several factors have contributed to price volatility for rare earth materials including political tensions, shifts in demand patterns, and supply disruptions. Prices for rare earth materials peaked in 2011 following changes in China’s export quotas and political tensions between China and Japan. In subsequent years, prices for most rare earths decreased significantly but were influenced by rising or falling demand for specific applications such as permanent magnets and phosphors.

1.1. Introduction

Despite their name, the rare earth elements (REEs) are a group of moderately abundant elements comprising the 15 lanthanides, scandium (Sc), and yttrium (Y). The lanthanides are the elements with atomic numbers 57 through 71, in the following order: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

Excluding scandium, REEs can be classified as either light rare earth elements (LREEs) or heavy rare earth elements (HREEs). The LREEs include the lanthanide elements from atomic number 57 (La) through atomic number 64 (Gd), and the HREEs include the lanthanide elements from atomic number 65 (Tb) through atomic number 71 (Lu). The division is based on the LREEs having unpaired electrons in the 4f electron shell and HREEs having paired electrons in the 4f electron shell. Yttrium is chemically similar to the HREE lanthanides and commonly occurs in the same minerals as a result of its similar ionic radius. Consequently, yttrium is considered an HREE even though it is not part of the lanthanide series (Rare Earth Industry Association, n.d.).

In rock‐forming minerals, rare earths typically occur in compounds as trivalent cations in carbonates, oxides, phosphates, and silicates (Mason and Moore, 1982, p. 46). Because REEs often share a divalent or trivalent charge and similar ionic radii, they are found together in a complex and diverse suite of minerals. Hundreds of REE‐bearing minerals have been identified in a variety of depositional environments (Van Gosen, et al., 2017).

1.2. Production

Most REE production has been from deposits where specific minerals (usually bastnaesite, loparite, monazite, xenotime) or ores such as ion‐adsorption clays are amenable to known industrial‐scale physical and chemical separation techniques.

Figure 1.1 Global estimated rare earth mine production (metric tons (Mt) of rare‐earth‐oxide equivalent).

Source: U.S. Geological Survey National Minerals Information Center, https://www.usgs.gov/centers/national‐minerals‐information‐center/rare‐earths‐statistics‐and‐information./United States Global Change /Public Domain.

LREEs have been produced predominantly from bastnaesite and monazite found in carbonatite and placer deposits, while production of HREEs has largely been from ion‐adsorption clays in Southern China and Burma (Myanmar). Sources of rare earths are evolving with changes in end uses, mining and processing technologies, and environmental concerns. Extensive research is ongoing to recycle REEs and recover REEs as byproducts of mine tailings and intermediate process streams.

Global production tripled during the period from 2010 to 2022 exceeding 300 thousand metric tons (KMt) of rare‐earth‐oxide (REO) equivalent in 2022. Since the 1980s, China has consistently led global production. Owing to increased production from Australia, Burma (Myanmar), and the United States, China’s contribution to the total has fallen from 90% in 2010 to about 70% in 2022. Concurrent with increased production outside of China, China increased its mine production quota to 210 KMt in 2022 from 89 KMt in 2010 (Figure 1.1).

1.2.1. Australia

Australia has significant production, reserves, and resources of REEs. Prior to the commissioning of the Mount Weld mining operations in 2011 by Lynas Corp., Australia’s REE mine production was as monazite–xenotime mineral concentrates, a byproduct of heavy‐mineral sands (HMS) mining and processing. HMS operations typically produce titanium, zirconium, and a variety of other mineral concentrates. In 2022, Australia’s REE production was based primarily on production of concentrates from the Mount Weld mining operations. Mount Weld is a carbonatite deposit with ore reserves of 18.6 million metric tons (MMt) containing 8.2% (1.53 MMt) REO equivalent. Total resources at Mount Weld were 54.7 MMt containing 5.3% (2.88 MMt) REO equivalent (Lynas Rare Earths Ltd., 2023). Mining at Mount Weld has been on a campaign basis in support of downstream crack, leach, and separation operations in Kuantan, Malaysia. The Mount Weld operations were initially designed to produce up to 66 thousand metric tons per year (KMt/year) of mineral concentrate containing about 26.5 KMt/year of REO equivalent (Lynas Rare Earths Ltd., n.d.). Lynas has plans to expand mine capacity and move its initial hydrometallurgical processing operations that produce mixed chemical concentrates from Malaysia to Australia.

In Western Australia, Northern Minerals Ltd. commissioned its pilot production at the Browns Range project in 2018. Hard rock ore containing xenotime was used to produce a mixed REE carbonate. In the Australian financial year 2022 (1st July 2021 to 30th June 2022), the pilot plant processed 8.5 KMt of ore and produced 70 Mt of carbonate. Indicated resources for the Browns Range project were estimated to be 4.54 MMt containing about 0.7% (31.7 KMt) REO equivalent. Probable reserves were 3.29 MMt containing about 0.7% (22.3 KMt) REO equivalent (Northern Minerals Ltd., 2022).

In 2020, heavy‐mineral sands producer, Iluka Resources Ltd., began processing a stockpile of mine tailings to produce monazite‐rich mineral concentrates at its Eneabba operations in Western Australia. The first phase of the project commenced in 2021, and the company produced 44 KMt of concentrate in 2020 and 58 KMt in 2021. In 2022, a second phase was completed to produce a 90% monazite concentrate from stockpiled tailings supplemented with ongoing process tailings. In the third phase of the project, the company planned to use monazite concentrates from potentially multiple sources to produce mixed and separated REE compounds. Reserves of the stockpile were estimated to be close to 1 MMt grading 84% heavy minerals. Monazite and xenotime comprised about 19% of the heavy minerals fraction (Iluka Resources Ltd., 2023a, p. 39; 2023b, p. 14).

Australia has been an active region for mineral exploration and development. Publicly listed companies developing projects with Joint Ore Reserve Committee (JORC)‐compliant rare earth reserves in Australia included Alkane Resources Ltd. (Dubbo Zirconia), Arafura Resources Ltd. (Nolans Bore), Australian Mines Ltd. (Sconi), Clean TeQ Holdings Ltd. (Sunrise), Hastings Technology Metals Ltd. (Yangibana), Lynas (Mount Weld), Northern Minerals Ltd. (Browns Range), Platina Resources Ltd. (Owendale), and Scandium International Mining Corp. (Nyngan). According to Geoscience Australia, economic demonstrated resources in Australia in 2021 were 4.26 MMt of REO equivalent (Hughes et al., 2023, p. 12).

1.2.2. Brazil

Brazil was an early producer of monazite mineral concentrates from heavy mineral sands deposits. In addition to mining, some chemical processing of monazite took place from 1949 to 1992 until environmental concerns closed the operations. In 2021, Brazil exported about 833 Mt of mineral concentrates that were produced from existing stockpiles of mixed heavy‐mineral concentrates. According to the Agência Nacional de Mineração, Brazil’s prior exports were derived from Indústrias Nucleares do Brasil inventories in Sao Francisco do Itabapoana (Andrade, 2019, p. 168).

In 2018, Companhia Brasileira de Metalurgia e Mineração (CBMM) conducted trial processing of monazite‐bearing tailings from its Araxá mine and processing operations in the State of Minas Gerais. CBMM Araxá operations produced niobium metal, ferroniobium, and compounds from pyrochlore ore containing about 2.3% niobium oxide. The plant capacity was 1 KMt/year of REO in the form of mixed compounds and pilot capacity for separated compounds was less than 20 Mt/year of REO equivalent. No production has been reported since 2018 (Ferreira Neto, 2021).

1.2.3. Burma (Myanmar)

Mine production in Burma (Myanmar) is estimated based on China’s reported imports of REE compounds from the country. Mining of ion‐adsorption clays has been reported in Kachin State, which borders China’s Yunnan Province (Htoi Awng, 2022). Although much of the production is undocumented, exports of REE compounds from Burma (Myanmar) to China were first reported in 2014 and peaked at an estimated 35 KMt of REO equivalent in 2021 (Zen Innovations AG, 2023).

1.2.4. Burundi

Rainbow Rare Earths Ltd. began trial mine production at its Gakara project in 2017. Although the company was targeting 100 Mt/month of concentrate production, the project was placed on care and maintenance in June 2021 at the request of the Government of Burundi. Measured resources are yet to be defined. The Gakara project includes numerous occurrences where REEs are hosted in bastnaesite‐rich veins and breccia pipes (Rainbow Rare Earths Ltd., 2022, p.56).

1.2.5. Canada

Canada has significant REE reserves and resources. According to Natural Resources Canada, Canada’s measured and indicated resources were over 15.1 MMt of REO in 2022. Numerous other projects in British Columbia, Saskatchewan, Ontario, Quebec, Newfoundland and Labrador, and Northwest Territories were reported to be active in 2021. Active REE mineral projects included Alces Lake, Crater Lake, Eldor (Ashram), Falcon Point, Port Hope Simpson (Foxtrot), Kipawa (Zeus), Kwyjibo, Montviel, Nechalacho, Red Wine, and Strange Lake. The Kipawa (Zeus) and Nechalacho–Basal Zone were at the feasibility stage of development. Active processing facilities included the Nechalacho–T Zone and Tardif Zone, SRC Processing Facility, Vital Metals Processing Facility, and the St‐Bruno Recycling Demonstration Plant (Natural Resources Canada, 2023).

In 2021, Vital Metals was conducting a mining demonstration project at the Nechalacho project in the Northwest Territories. Mineral concentrates were shipped to Saskatchewan, for further processing. In the North T deposit where the company was sourcing ore for the demonstration, total resources were 94 KMt containing about 9.1% REO. Using a 0.1% Nd oxide cutoff, total resources for the Tardiff Upper Zone were 95 MMt containing about 1.5% REO (Vital Metals, 2022, p. 18).

1.2.6. China

China has dominated the supply of mine production and downstream products for decades. The Government of China sets production quotas for the mining and separation of REEs. However, actual Chinese production is estimated to have exceeded the quotas, as illegal production has been a concern since 2010. The illegal production has been difficult to quantify; however, it was estimated by one news source to have been 60 KMt in 2017 and was expected to fall to 8 KMt in 2021 (Argus Media Group, 2020).

Owing in part to illegal mining activities and environmental concerns, China has been consolidating its rare earth industry and enforcing more restrictive environmental policies. In 2022, China’s Ministry of Land and Resources (MLR) allotted most of the mining production quota to four entities (China Rare Earth Group Co., Northern Rare Earth, Xiamen Tungsten Co., and Guangdong Rare Earth Industry Co.) In 2021, the China Rare Earth Group was established to consolidate production from Chinalco, Minerals Rare Earth, and Southern Rare Earth. The mining quota for 2022 was set at a record high of 210 KMt, a 25% increase from 168 KMt in 2021 and more than triple the 89 KMt set in 2010. China’s reserves were estimated to be 44 MMt of REO and the identified resources were estimated to be 1,400 MMt of REO (Argus Media Group, 2022a).

1.2.7. India

India is one of the earliest sources of monazite concentrates with production beginning in the early 1900s. Monazite concentrates containing REEs are produced in India as a byproduct of heavy mineral sands mining operations that also produce titanium and zirconium concentrates. Production capacity of monazite concentrates is reported to be 6 KMt/year at the Manavalakurichi operations and 240 Mt/year at the Chavara operations. A processing plant was commissioned in 2015 with more than 11 KMt/year of capacity to produce mixed rare earth compounds from monazite concentrates.

India’s monazite resources in heavy mineral sands deposits were estimated to be 12.5 MMt of monazite. The distribution by state was Andhra Pradesh (3.69 MMt); Tamil Nadu (2.46 MMt); Odisha (3.06 MMt); Kerala (1.84 MMt); West Bengal (1.2 MMt); and Jharkhand (21 KMt) (Indian Bureau of Mines, 2020).

1.2.8. Madagascar

In Madagascar, monazite concentrates are a byproduct of heavy mineral sands mining operations near Fort‐Dauphin that produce titanium and zirconium mineral concentrates (Rio Tinto plc, 2022). In 2018, initial shipments of mixed heavy mineral concentrates containing monazite were produced from mine tailings and exported to China. Based on the unit value of China’s imports of these concentrates from Madagascar, the monazite content was estimated to be significantly less than those from other sources (Zen Innovations AG, 2023). Resource estimates for heavy mineral sands were not available at a national level. At the Tantalus ionic clay project in northern Madagascar, measured and indicated resources were 198 MMt containing 897 parts per million (177 KMt) of REO equivalent. In 2019, China Nonferrous agreed to provide engineering procurement and construction services to the project, purchase up to 3 KMt of output within 3 years of commissioning, and make future investments into the project (ISR Capital, 2019; Tantalus Rare Earths, 2014).

1.2.9. Malaysia

Historically, Malaysia produced monazite and xenotime concentrates that were recovered as a byproduct of tin and titanium–zirconium heavy mineral sands operations. In 2021, Malaysia produced and exported less than 100 Mt of REO equivalent in mineral concentrates. In downstream processing, an additional 15.6 KMt of REO equivalent in compounds was produced from Australian mineral concentrates (Lynas Rare Earths Corp., 2022b, p. 8).

1.2.10. Russia

Russia’s Lovozersky GOK produces loparite concentrates from its Karnasurt Mine in Murmansk. Loparite concentrates are further processed into mixed rare earth compounds by Solikamsk Magnesium Works. Russia’s mine production of REO was estimated to have been 2.6 KMt in 2021 (U.S. Geological Survey, 2023). Russia’s exports of REE compounds totaled 5.6 KMt (gross weight) in 2021 and Estonia (80%) and China (16%) were the leading destinations (Zen Innovations AG, 2023).

1.2.11. South Africa

Although South Africa has no reported mine production of rare earths, monazite concentrates are a potential byproduct from heavy‐mineral sands production at the Richards Bay and Exxaro Resources mining operations. In addition to recovery from byproduct sources, feasibility studies have been completed on the Steenkampskraal project in the Western Cape province where reserves were estimated to be 605 KMt containing 14.4% (87 KMt) of REO equivalent (Liedtke, 2019). Prefeasibility studies were also started at the Phalaborwa, Glenover, and Zandkopsdrift REE projects (Frontier Rare Earths Ltd., n.d.; Galileo Resources Plc, n.d.; Rainbow Rare Earths Ltd., 2022).

1.2.12. Tanzania

No production of REE mineral concentrates have been reported for Tanzania; however, feasibility studies have been completed on the Ngualla project in southwest Tanzania. Reserves were reported to be 18.5 MMt containing 4.8% (887 KMt) REO equivalent using a 1%‐REO cutoff grade. Resources were reported to be 210 MMt containing 2.15% (4.62 MMt) REO equivalent, and 93% of the resources were classified as measured and indicated (Peak Resources Ltd., 2022, p. 8, 92, 94).

1.2.13. Thailand

Thailand is known to be an intermediate processer of tin tailings and mixed HMS concentrates and produces monazite–xenotime concentrates that are then exported to China. During the period from 2010 to 2022, production fluctuated between a low of less than 1 KMt REO equivalent in 2012, 2013, and 2015, and a high of 8.1 KMt REO equivalent in 2022. Estimates of Thailand’s reserves and resources were not available (U.S. Geological Survey, 2023).

1.2.14. Vietnam

Despite limited commercial‐scale mine production, Vietnam has significant reserves and resources of rare earths. Ore reserves have been estimated to be 22 MMt of REO equivalent. Notable REE deposits include Dong Pao (Lai Chau Province), Nam Xe (Lai Chau Province), and Yen Phu (Yen Bai Province). Historically, mine production from Vietnam was largely based on monazite–xenotime concentrates recovered from HMS. More recently, REEs have been recovered from ion‐adsorption clay deposits. Vietnam has commercial‐scale downstream capacity to produce REE metals and compounds. In 2022, Vietnam’s exports of REE compounds and metals were 2.5 KMt and 4.3 KMt, respectively (Zen Innovations AG, 2023).

1.2.15. United States

Mine production of rare earths in the United States was almost entirely from bastnaesite mineral concentrates produced at Mountain Pass, CA, where mining operations were most recently recommissioned in 2018. Monazite concentrates were also produced as a separated concentrate or included as an accessory mineral in mixed HMS produced in the southeastern United States. In 2022, mine production at Mountain Pass was reported to be 42.5 KMt of REO. Reconfigured separation operations were scheduled to be recommissioned in 2023 (MP Materials Corp., 2023).

Government agencies in the United States have been partnering with industry and academia to foster domestic production and identify new byproduct recovery sources of rare earths such as coal fly ash. In 2020 and 2021, respectively, Lynas announced plans to establish light and heavy separation operations in the United States with support from the U.S. Department of Defense (Lynas Rare Earths Ltd., 2021, 2022a).

1.3. Trade

Rare earths are traded on a global basis and are contained in mineral concentrates, compounds, and metals. Global trade flows of rare earths are usually reported on a gross weight basis under selected harmonized system (HS) and country‐specific trade codes. The HS codes are common between countries to the 6‐digit level. Country specific codes like the U.S. Harmonized Tariff Schedule may have up to 10 digits and add specificity for categorizing either imports or exports or both. Rare earths are also contained in numerous downstream products such as catalysts, batteries, and magnets. Downstream codes are often not specific to rare earths and it is difficult to estimate their rare earth content.

1.3.1. Mineral Concentrates

For mineral concentrates, there is not a 6‐digit HS code dedicated to rare earths. However, monazite and xenotime concentrates are usually traded under the HS code 2612.20 (defined as thorium ore and concentrates). At the 8‐digit code level, China Customs has a dedicated code (2530.90.20) for rare earths (defined as ores of rare earth metals).

China is the largest and one of only a few countries that has the capability to process rare earth mineral concentrates at an industrial scale. In addition to being the largest mine producer, China is the largest importer of mineral concentrates. The volume of concentrates imported into China has increased significantly in recent years rising from 12 KMt in 2010 to over 126 KMt in 2021. The unit value of concentrate imports into China has varied significantly by country reflecting the differences in grade and quality of source materials. In 2010, China imported 12 KMt of concentrates, and import levels remained below 10 KMt/year until 2018 when imports from the United States and Madagascar increased the volume significantly. In the 5‐year period between 2018 and 2022, the United States was the leading supplier of rare earth mineral concentrates to China, accounting for more than 60% of China’s imports. Madagascar supplied 23% of imports during this period and China’s total volume of imports peaked in 2021 at 127 KMt (Figure 1.2).

Malaysia is the second largest importer of rare earth mineral concentrates. Malaysia’s production of REO compounds in Kuantan is sourced entirely from imports of mineral concentrates from Australia. The Mount Weld mineral concentrate operations were commissioned in 2011 and exports to Malaysia began in 2012. Although these exports are mineral concentrates, they have been included under the HS code for rare earth metals (2805.30). Imports from Australia to Malaysia of 50 KMt in 2014 may include misclassified material, as this import level does not align well with the 7.2 KMt of REO production of REO compounds in Malaysia (Figure 1.3).

Figure 1.2 China’s imports of rare earth mineral concentrates by country of origin (metric tons, gross weight).

Source: Global Trade Tracker, https://www.globaltradetracker.com/.

Figure 1.3 Malaysia’s imports of rare earth metals from Australia (metric tons, gross weight).

Source: Global Trade Tracker, https://www.globaltradetracker.com/.

1.3.2. Compounds

Trades of rare earth compounds are reported on a gross weight basis under the HS code heading 2846 (defined as compounds, inorganic or organic, of rare earth metals, of yttrium or of scandium, or of mixtures of these metals). During the period from 2010 to 2021, the leading global importers of REE compounds, in descending order of gross weight, include China, Japan, United States, Germany, and Estonia. In 2016, Burma (Myanmar) emerged as a significant source of rare earth compounds supporting China’s downstream processing into separated compounds and metals. Satellite imagery shows significant growth in the mining of ion‐adsorption clays in Kachin State, Burma (Myanmar), similar to mining operations in China’s Jiangxi Province. Coinciding with increased imports of compounds, several operations in the Jiangxi Province were idled over environmental concerns in 2017 (Argus Media Group, 2020). With limited ability to separate mixed compounds, Japan, United States, and Germany imported mixed and separated compounds (primarily from China) for downstream processing into catalysts, polishing compounds, etc. Estonia imported mixed compounds primarily from Russia and the United States to support its separation and metallurgical operations in Sillamäe (Figure 1.4).

1.3.3. Metals

Imports and exports of rare earth metals are reported on a gross weight basis primarily under the HS code heading 2805.30 (defined as rare earth metals, scandium and yttrium, whether or not intermixed or interalloyed). On a gross weight basis, global trade in metals is significantly less compared with trade in compounds or concentrates. Japan was the leading importer of REE metals with about 60% of global imports. The next three countries (Norway, India, and the United States) sum to about 15% of global imports during the period from 2010 to 2021. Global trade in metals reached a high of 14.2 KMt in 2021 compared with 10.7 KMt in 2020.

Figure 1.4 Global importers of rare earth compounds (metric tons, gross weight).

Source: Global Trade Tracker, https://www.globaltradetracker.com/.

In addition to trade under 2805.30, significant volumes of REE metals are contained in other ferrous and nonferrous alloys and are traded under different base metal trade codes. Tracking these can be problematic. For example, ferrocerium is traded under the HS code 3606.90 (defined as ferrocerium and other pyrophoric alloys in all forms). The REE content within this HS code varies significantly and other pyrophoric materials that do not contain REEs are included within the data. Another significant volume of rare earths is contained in finished and semifinished materials like permanent magnets (HS 8505.11 defined as permanent magnets and articles intended to become permanent magnets after magnetization). Specific HS trade codes for rare earth permanent magnets (NdFeB and SmCo) are not defined at the 6‐digit level but are available with certain country‐specific codes like the HTS codes for NdFeB‐sintered magnets (8505.11.0070) and SmCo‐sintered magnets (8505.11.0050) (Figure 1.5).

Figure 1.5 Global importers of rare earth metals.

Source: Global Trade Tracker, https://www.globaltradetracker.com/.

1.4. Prices

Unlike base metals, rare earths are not traded on the Commodity Exchange (COMEX) or the London Metal Exchange (LME), but price data for rare earths are available from a variety of sources. For LREEs, the data are available; however, for certain HREEs that are used in niche markets, the data are unavailable or have a limited price history. For purposes of discussion, it is useful to group certain elements that are relatively close on the periodic table, are treated together during the separation processing steps, or have overlapping uses. For this review, prices are reviewed for the period 2010–2022. Thulium prices were not available and only partial data for this time period were available for gadolinium, holmium, and erbium oxides.

Several factors have contributed to price volatility for rare earth materials including political tensions, shifts in demand patterns, and supply disruptions. Concerns for the availability of rare earths rose to global attention in 2010. In July 2010, China’s Ministry of Commerce announced that China would cut its exports of rare earth minerals by about 72% for 2010. Consequently, most of the 2010 quota had already been met. In September 2010, China’s rare earth exports to Japan decreased dramatically following a territorial waters incident between the two countries (Grasso, 2013). By 2011, prices for rare earth materials had increased to record highs and there were widespread reports of illegal mining, processing, and exports of China’s rare earths. Since 2010, prices of some REEs have experienced significant price volatility owing to shifting demand and limited availability for certain HREEs.

Growing demand for rare earth magnets have reshaped the market over the last decade. Since REEs are mined and extracted together, the supply of specific REEs related to magnet materials has outpaced demand for certain elements while being in deficit for other elements. Subsequently, prices of some materials have declined significantly over the 2010–2022 period (Argus Media Group, 2023).

1.4.1. Cerium and Lanthanum

Cerium and lanthanum are the most abundant REEs and are often used together in various applications. The applications that require the most cerium and lanthanum, by volume, include catalysts, glass additives, polishing, and metallurgical applications. These two elements also serve other diverse markets and are used in a variety of other applications such as magnets, lasers, and ceramics.

Prices for cerium and lanthanum oxides have followed very similar trends. Prior to 2007, average prices for both oxides were less than $2/kg. China’s restrictions in exports combined with other factors caused a spike in prices that peaked in 2011 at over $100/kg for both oxides. In the following year, average prices decreased by about 77%. Excluding moderate increases in 2017 and 2018, prices have continued to decline post 2011. In 2022, the average annual prices for cerium and lanthanum oxides were about $1.50/kg (Figure 1.6).

Figure 1.6 Cerium and lanthanum oxide prices in U.S. dollars per kilogram (FOB China).

Source: Argus Media group (Argus Metals International), https://metals.argusmedia.com/.

1.4.2. Neodymium and Praseodymium

Neodymium–iron–boron (NdFeB) permanent magnets are the leading end use for both neodymium and praseodymium. Other end uses include catalysts, pigments, and other metallurgical uses typically as alloying elements. NdFeB magnets typically contain greater than 30% REE elements by weight with the majority of the REE content as neodymium and praseodymium.

Average prices for neodymium and praseodymium oxide peaked in 2011 at about $233/kg and $196/kg, respectively. Since 2011, fluctuations in prices have been mixed with numerous double‐digit year‐on‐year increases and decreases. In 2022, the average prices for neodymium and praseodymium oxides significantly increased to $134/kg and $128/kg, respectively, from $49/kg and $47/kg in 2020 (Figure 1.7).

Figure 1.7 Neodymium and praseodymium oxide prices in U.S. dollars per kilogram (FOB China).

Source: Argus Media group (Argus Metals International), https://metals.argusmedia.com/.

1.4.3. Samarium and Gadolinium

Samarium and gadolinium are used predominantly in magnetic applications. Samarium is used in samarium–cobalt (Sm–Co) permanent magnets, which have a lower energy product than neodymium magnets. Although they have a lower magnetic strength, the advantage of Sm–Co magnets over NdFeB magnets is that they are capable of being used at higher operating temperatures before they lose magnetism. In 2011, the annual average price for samarium oxide increased sixfold, compared with 2010. By 2013, the average price was less than that in 2010. Subsequently, oxide prices reached a low of less than $2/kg in 2016 and have risen above $3/kg in 2022.