Critical Materials

By Alexander King

Critical Materials takes a case-study approach, describing materials supply-chain failures from the bronze age to present day. It looks at why these failures occurred, what the consequences were, and how they were resolved. It identifies key lessons to guide responses to current and anticipated materials shortages at a time when the world’s growing middle class is creating unprecedented demand for manufactured products and the increasingly exotic materials that go into them. This book serves as a guide to materials researchers and industrial end-users for finding effective approaches to shortages of specialty materials.

The lessons in the book are also appropriate to those who use materials and for those involved in manufacturing supply-chain management and industrial design.

• Instructs the reader on how to select the most effective strategies to deal with materials supply-chain failures
• Discusses technical feasibility, economic viability and the political context
• Includes an extensive use of case studies to illustrate key concepts of criticality

• Language: English
• Publisher: Elsevier Science
• Release date: Oct 22, 2020
• ISBN: 9780128187906

Alexander King

Alex King is a professor of Materials Science and Engineering at Iowa State University. He earned his doctorate from Oxford University and did his post-doc work at both Oxford University and MIT. He went on to join the faculty at the State University of New York at Stony Brook, where he also served as the Vice Provost for Graduate Studies (Dean of the Graduate School). He was the Head of the School of Materials Engineering at Purdue from 1999 to 2007. From 2008 until 2013 he was the Director of DOE’s Ames Laboratory and became the Founding Director of the Critical Materials Institute from 2013 through 2018. Dr. King is a Fellow of the Institute of Mining Minerals and Materials; ASM International; and the Materials Research Society. He was also a Visiting Fellow of the Japan Society for the Promotion of Science in 1996 and a US Department of State Jefferson Science Fellow for 2005-06. He served as the President of MRS in 2002, Chair of the University Materials Council of North America from 2006-07, Co-chair of the Gordon Conference on Physical Metallurgy in 2006, and Chair of the APS Interest Group on Energy Research and Applications for 2010. Dr. King was named the recipient of the 2019 Acta Materialia Hollomon Award for Materials and Society. Alex King delivered a TEDx talk on critical materials in 2013 and was the TMS & ASM Distinguished Lecturer on Materials and Society in 2017. He is currently a scientific adviser for Harvard’s Material Alchemy (described as “translating science into commercial products that use sustainable materials”) and a member of the Advisory Board of CHiMaD (the Center for Hierarchical Materials Design, funded by the Department of Commerce, and led by Northwestern University).

Book preview

Critical Materials

First Edition

Alexander King

Table of Contents

Cover image

Title page

Copyright

Acknowledgments

Abbreviations and acronyms

Preface

1: What happened to the rare earths? Monopoly, price shock, and the idea of a critical material

Abstract

The essentiality of the rare earths

Rare earth sources

Rare earth supply challenges—2005–15

After the price spike

Lessons learned: The price spike in hindsight

Coda: Every challenge is also an opportunity

2: This is not new. A short history of materials criticality and supply-chain challenges

Abstract

Copper and the end of the Bronze Age (~ 1200 BCE)

The Venetian monopoly on glass

Cordite in World War I (1914–18)

Silk and nylon (the 1930s and 1940s)

World War II (1939–45)

Old lead (1978)

Cobalt (1978)

Niobium (1979)

Molybdenum (1980 and 2004)

Tantalum (1997, 2000, and 2008)

Photovoltaic silicon (mid-2000s)

Rhenium (2006–08)

Lessons learned

3: Assessing the risks

Abstract

Defining critical materials

Assessments of materials criticality

Consistency and contrast

Variation of criticality over time

Regional perspectives on criticality

Indicators of criticality

What does criticality mean?

Consequences of criticality

Tipping points. What takes us from criticality to crisis?

Lessons learned

What will we need?

4: What changed after the rare earth crisis?

Abstract

Impacts of the rare earth crisis

Conflicts and conflict resolution

The supply side

The demand side

Postcrisis rare earth prices and utilization

Lessons learned

5: Mitigating criticality, part I: Material substitution

Abstract

The challenge of inventing materials on demand

Improving the forecast

Using existing materials

Increasing the speed of new material discovery and deployment

Lessons learned

6: Mitigating criticality, part II: Source diversification

Abstract

How are mines developed?

Conventional mines

Unconventional sources

Coproduction

Progress since the rare earth crisis

Lessons learned

7: Mitigating criticality, part III: Improving the stewardship of existing supplies

Abstract

Urban mines versus conventional mines

Regulatory versus economic drivers

Reducing manufacturing waste

In-process recycling

End-of-life recycling

Recycling as a response to criticality: Successes and failures

What fraction of current need can be met by recycling?

Emerging targets for recycling

Potentially viable recycling technologies

Lessons learned

8: Tactics and strategies for the future

Abstract

What have we learned?

Time is the biggest challenge

Summary

Epilog: Criticality in the time of coronavirus

Index

Copyright

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Notices

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Acknowledgments

This book is an attempt to summarize what I have learned in the process of setting up and running the Critical Materials Institute for its first 5 years, and I have had many teachers. The late Karl Gschneidner, Jr. was my mentor on all things related to the rare-earth elements, and he is greatly missed. All of the people of CMI have contributed to my education but especially its leadership team, which has included Iver Anderson, Gretchen Baier, Joni Barnes, Deb Covey, Rod Eggert, Cynthia Feller, Yoshiko Fujita, Dan Ginosar, Chris Haase, Carol Handwerker, the late Scott Herbst, Ed Jones, Tom Lograsso, Scott McCall, Bruce Moyer, Eric Peterson, Brian Sales, Adam Schwartz and Eric Schwegler. Others have provided notable input, specific contributions, and moments of enlightenment or levity, including Jenni Brockpahler, Steve Constantinides, Bill McCallum, Ikenna Nlebedim, Duane Johnson, Richard LeSar, John Ormerod, Ryan Ott, Orlando Rios, Sadas Sadasivan, Alok Srivastava, Stan Trout, Patrice Turchi, Jeff Wang, David Weiss, and probably a few others who have slipped my memory.

The US Department of Energy supported the learning phase of this work by funding the Critical Materials Institute through the Division of Energy Efficiency and Renewable Energy’s Advanced Manufacturing Office. This book was written with the support of the Iowa State University of Science and Technology.

Finally, my wife, Christine, has provided steadfast forbearance and stability amid the chaos, along with some timely professional consultation on information resources.

Abbreviations and acronyms

ACREI Association of Chinese Rare Earth Industries

AI artificial intelligence

AIM accelerated insertion of materials

AIST The National Institute of Advanced Industrial Science and Technology (Japan)

ALMR Association of Lamp and Mercury Recyclers

AMD acid mine drainage

AMR anisotropic magnetoresistance

ASTM American Society for Testing and Materials

ASX Australian Stock Exchange

At. No. atomic number

BCE before the Christian (or common) era

BFR brominated flame retardant

BGS British Geological Survey

CAGR compound annual growth rate

CALPHAD calculation of phase diagrams

CAPEX capital expenditures

CENRS Committee on Environment, Natural Resources, and Sustainability (of NSTC)

CES Cambridge Engineering Selector (from Granta Design)

CFL compact fluorescent lamp

CMI Critical Materials Institute

COVID-19 coronavirus disease 2019

CPU central processor unit

CRIRSCO Committee for Mineral Reserves International Reporting Standards

CRM critical raw material

CRT cathode ray tube

DARPA Defense Advanced Research Projects Agency (the United States)

DfD design for disassembly

DFS definitive feasibility study

DFT density functional theory

DHS Department of Homeland Security of the United States

DKB designer knowledge base

DOE Department of Energy of the United States

DRAM dynamic random-access memory

DRC Democratic Republic of the Congo (since 1997), formerly Zaire

EC European Commission

EEZ exclusive economic zone

EU European Union

EV electric vehicle

FOB free on board at shipping point (means that ownership is transferred to the purchaser when goods leave the named shipping point)

GM General Motors

GMR giant magnetoresistance

GPS global positioning system

GRS government rubber styrene

GTP Global Tungsten and Powders Corporation

HD hydrogen decrepitation

HDD hard disk drive

HDDR hydrogenation, disproportionation, desorption, and recombination

HEU high-enriched uranium

HEV hybrid electric vehicle

HREE heavy rare-earth element

HSLA high strength, low alloy (of steels)

IC integrated circuit

ICE internal combustion engine

ICME integrated computational materials engineering

iNEMI International Electronics Manufacturing Initiative

IR infrared

ISO International Standards Organization

JCG Japan Coast Guard

JORC Joint Ore Reserves Committee (produces the Australasian code for reporting of exploration results, mineral resources, and ore reserves)

LCO lithium cobalt oxide

LENS laser engineered net shaping

LEU low-enriched uranium

LIBS laser-induced breakdown spectroscopy

LME London Metal Exchange

LREE light rare-earth element

MD molecular dynamics

MESS multiple elements from a single source

MGI materials genome initiative

MRI magnetic resonance imaging

MRT molecular recognition technology

MSX membrane solvent extraction

NASA National Aeronautics and Space Administration

NEDO New Energy and Industrial Technology Development Organization (Japan)

NI-43101 National Instrument 43-101 (Canadian resource assessment and reporting standard)

NIST National Institute of Standards and Technology (the United States)

NMC lithium nickel manganese cobalt oxide

NORM naturally occurring radioactive material

NRC National Research Council (of the US National Academies of Sciences, Engineering, and Medicine)

NSTC National Science and Technology Council (of the United States)

NYMEX New York Mercantile Exchange

OPEX operating expenditures

PEA preliminary economic assessment

PFS preliminary feasibility study

PGM platinum group metal

ppm parts per million

PRC Peoples’ Republic of China

PV photovoltaic

PVC polyvinyl chloride

QP quench and partition

R&D research and development

RAM random-access memory

REE rare-earth element

REO rare-earth oxide

REPM rare-earth permanent magnet

REY rare earths plus yttrium, i.e., the lanthanides plus yttrium

ROI return on investment

ROW Rest of World, i.e., all countries except China

SAMREC South African Mineral Reporting Codes

SCSMSC Subcommittee on Critical and Strategic Mineral Supply Chains (of NSTC)

SOFC solid oxide fuel cell

SX solvent extraction

TBC thermal barrier coating

TREO total rare-earth oxide, i.e., the sum over all of the rare-earth elements

TRL technology readiness level

TSX Toronto Stock Exchange

US, USA The United States (of America)

UV ultraviolet

WTO World Trade Organization

WWI World War I

WWII World War II

XRF X-ray fluorescence

YSZ yttria-stabilized zirconia

Preface

Alexander King, Ames, IA, United States

I did not set out to write this book.

In 2010 a group of researchers gathered to design an agenda for research and development that aimed at alleviating the challenges to rare-earth supplies that were then emerging. In 2013 the Critical Materials Institute was stood up, and I served as the director for its first 5 years. As we and others around the world pursued various lines of research, we learned a lot of things that did not work and also found a few that did. This volume is an attempt to summarize that knowledge, as logically and methodically as such recent hindsight allows, to create a guide for others working threats to materials supply chains.

This is not a book about materials science.

Although a certain amount of materials science is included, it is usually only described at the level of an introductory college class, and much more detailed texts are available if you want to read deeply into that subject. This book is about the intersections of materials science, manufacturing and public policy. My goal has been to include just enough about each of these topics to enable the practitioners of the others to understand each other and have enough vision into their different worlds to recognize where their efforts may or may not align. When they align, impact is possible; when they do not, all effort is for naught.

I draw on historical and recent examples of R&D efforts that have helped to alleviate material shortages, along with cases where they have failed to have any impact despite the excellence of the research. Lessons learned from these case studies are used to identify the traits of successful programs and the pitfalls that should be avoided in creating research-based solutions to material supply challenges.

1: What happened to the rare earths? Monopoly, price shock, and the idea of a critical material

Abstract

Rare earth prices surged to unprecedented levels in 2011 creating concerns about the security of their supplies and triggering a broad range of responses. Some of the conditions that led to the rare earth crisis also apply to other industrial feedstocks and the interrelated economics and technologies of critical materials rapidly emerged as an urgent area of research and development activity.

Keywords

Rare earths; Price shock; Monopoly; China; Critical material

Every manufactured thing is made of some kind of material.

In some cases manufacturers are free to choose among different materials that can meet their needs, and they make selections according to the cost or properties of the available materials, to optimize profit or performance.

In other cases there is only one material that meets the needs of the manufactured object. Thomas Edison’s incandescent electric lightbulb famously depended on the identification of a material to use for the hot, glowing filament, and after testing hundreds or maybe thousands of possible materials, tungsten was identified as the only one that met the needs: It could be heated by an electric current, and it did not melt at the elevated temperatures where it would glow and provide light.

Materials that are necessary for a particular product, like tungsten in lightbulbs, are regarded as essential. You can’t make the product without them, and there are no ready substitutes to use if you can’t get them. Today’s technologies are full of essential materials: All of our smart devices rely on data processing enabled by silicon and several ancillary materials; nuclear reactors need uranium to produce heat that is eventually converted to electricity; early photocopiers and laser printers were enabled by the particular properties of selenium sulfide print drums; electrical energy storage is dominated by rechargeable batteries made with lithium; and despite increasing use of carbon fibers, the aviation industry still depends very heavily on aluminum-based structures.

Essential materials have particular properties that make them work: Tungsten has a very high melting point, silicon is a semiconductor, uranium’s atomic nucleus can be fissile, selenium sulfide is a photoconductor that only transmits electricity when it is exposed to light, lithium is easily ionized and transported between the electrodes of batteries, and aluminum has high strength relative to its weight and cost. Because of their properties, these (and many other) materials are, or have been, essential. As will be clear from some of these examples, essentiality is not a permanent property of a material: Incandescent lighting has been replaced by other more efficient technologies, nuclear power is increasingly unpopular in many parts of the world, selenium sulfide has been replaced by amorphous silicon in laser printers, and aluminum is being replaced by carbon fiber composites in some airplanes.

The rare earths are a particular set of chemical elements whose properties make them essential to a wide range of products. These once-obscure substances started to gain attention in the late 2000s because they are essential to many technologies, and their supplies were perceived to be threatened.

When an essential material has a risk of supply disruptions, it is considered a critical material, and when supply concerns erupted about the rare earths, they sparked broader interest in the general issue of critical materials. A decade after the rare earth price shock, we have learned a great deal about criticality, materials supply crises, and how best to manage them.

The essentiality of the rare earths

The rare earths comprise 17 chemical elements including all of the lanthanides, the 15 elements from lanthanum (atomic number 57) to lutetium (At. No. 71). Scandium (At. No. 21) and yttrium (At. No. 39) are usually included in the set of rare earth elements (REEs), because they also belong to Group 3 of the periodic table and are closely related to the rare earths in terms of their chemical behavior. All of the rare earth elements are shown in Fig. 1.1.

Fig. 1.1 The rare earth elements include all of the lanthanide series along with scandium and yttrium.

The definition of the set of elements that belong to the rare earth category is not always consistent. Some authors exclude or ignore scandium, and some authors refer to the rare earths plus yttrium (REY) implying that they only consider the lanthanides to be true rare earths. Distinctions are frequently drawn between light and heavy rare earths, based upon their atomic weights, but the borderline between light and heavy is variable, and some people apply the label medium to an intermediate group, also of variable membership. Despite this variability, distinctions between light and heavy rare earths are useful. Rare earth mines are typically described as being richer or poorer in one or other category—and yttrium is more often associated with heavy rare earths in this context, so it is considered a heavy rare earth, despite its relatively low atomic weight.

The first rare earths were discovered in 1787, in the form of a black mineral from a quarry in Ytterby, Sweden, near Gothenburg. From this rock the Finnish chemist Johan Gadolin extracted an oxide (or earth), which he named ceria, after Ceres, the Roman goddess of agriculture, grain crops, fertility, and motherly relationships. He published the discovery in 1794 [1]. Only later were the various rare earths separated from each other and reduced into elemental metals, but as they were successively isolated, uses for them also developed. A newly discovered rare earth bearing mineral was named gadolinite in 1800, in Gadolin’s honor. When element number 64 was discovered in 1880, it was named after him, too—gadolinium—even though it is not extracted from gadolinite.

Like gadolinium, most of the rare earths were discovered in the late 19th and early 20th centuries, following the development of the periodic table by Mendeleev, in 1867 [2]. The systematic organization of the chemical elements predicted the existence of elements that were not yet known, and a large part of chemical science of that time was devoted to finding them. It was assumed that the lanthanides must be rare because they were not found very easily, and the term rare earth stuck. In fact the rare earth elements are not so much rare as they are elusive. Except for promethium (At. No. 61), which decays radioactively, has no stable isotopes, and is not found in nature, the rare earths are fairly abundant in the crust of the Earth with cerium being the most abundant rare earth and the 25th most-abundant element of all. Overall, elemental abundance in the Earth’s crust are shown in Fig. 1.2, but this does not tell the whole story: the REEs are neither commonly found in isolation nor in very high concentrations. While significant geologic concentrations of iron, nickel, and other elements exist as ores in many places on Earth, the rare earths are rather more uniformly distributed, and where they are locally concentrated, they tend to be found in mixtures and are very hard to separate from each other and also from oxygen. Their chemical similarity is responsible for both their colocation and the difficulty of separating them. Their high affinity for oxygen not only makes it hard to produce metal from their ores but also drives some of their essential uses.

Fig. 1.2 The abundance of the elements in the earth’s crust, relative to the abundance of silicon. Despite their name the rare earths are not exceptionally scarce. From G.B. Haxel, J.B. Hedrick, G.J. Orris, Rare Earth Elements—Critical Resources for High Technology" (fact sheet), US Geological Survey. https://pubs.usgs.gov/fs/2002/fs087-02/fs087-02.pdf .

Some of the earliest uses were pioneered by Carl Auer von Welsbach [3]. In many cases former uses have ceased, either because the application became obsolete or alternative materials were identified, but some of Auer’s inventions have had a surprising persistence.

Lanthanum, cerium, and yttrium oxides, combined with magnesium oxide, formed the first commercial rare earth material, and it was used for gas-lamp mantles. Auer’s 1885 patent on Actinophor was the basis of a business that he started in 1887. Although the material had good emissive power for light and it glowed brightly when heated, the color spectrum was greenish and not considered very attractive, so in 1890 Auer and Haittinger patented an improved gas mantle comprising 99% thoria and 1% ceria [3]. This produced a whiter light, and it became the dominant gas mantle material worldwide, lasting until electric lighting eventually replaced gas: it remains in use today for some gas lanterns such as those used by recreational campers. Thoria is not a rare earth since thorium is an actinide element, not a lanthanide, but the need to find a source for thoria had a profound impact on the production of rare earths.

Among other uses for the rare earths, carbon arc lamps, especially those used in large movie projectors, were significantly enhanced by additions of lanthanum and other rare earth elements to the carbon electrodes, but like gas lamps, this technology is largely a thing of the past.

Mischmetal was originally developed by Auer as a mixture of 30% iron and 70% rare earths and today typically contains roughly 50% cerium, 25% lanthanum, and small amounts of neodymium and praseodymium. It is used as a spark generator for cigarette lighters and welding torch igniters—an enduring use over many decades [3] made possible by the highly exothermic reaction of the rare earths with atmospheric oxygen, when a fresh surface is exposed by scraping.

In the 1920s praseodymium began to be used as a yellowish-orange stain for ceramics and remains in use for this application today. Around the same time, neodymium started to be used to tint glass for both decorative use and for industrial goggles for glassworkers and welders. It also remains in use for this purpose. General Electric’s premium Reveal incandescent lightbulb line used neodymium-tinted glass envelope to provide an improved color balance relative to other incandescent lamps, but this application has been replaced by a new LED version of the Reveal product line, which develops its characteristic spectrum through different means.

All of these uses of rare earths (with the possible exception of welding goggles) may now be considered to be somewhat inessential, optional, or boutique applications that are either small in volume, are easily replaced, or have otherwise been made obsolete.

The 1960s, however, saw two new applications for rare earth elements, in which unique benefits emerged from the electronic orbital structure of the lanthanides. These are the first large-scale, initially nonsubstitutable uses for rare earth materials. Zeolite catalysts for crude oil cracking, known as fluid cracking catalysts, or FCCs, are stabilized by the addition of rare earths and achieve significantly longer life as a result of the addition of yttrium and other REEs. The first generation of color televisions suffered from poor color saturation because of the low output of the available red phosphors and the resulting need to mute the green and blue phosphors to maintain a reasonable color balance. This all changed with the discovery of a brighter red phosphor, europium-doped yttrium orthovanadate, which was first adopted by Zenith Electronics, and then industry wide. Truly essential uses for the rare earths were in place for the first time, at least if you believe that color TVs are essential.

Cerium oxide, or ceria, is used in powder form as a chemical-mechanical planarization medium for silicon wafers and as optician’s rouge for polishing glass, combining excellent abrasive properties with a mild chemical attack of the target materials. It also has widespread applications in catalysis, being used in some automotive catalytic converters and in the coatings of self-cleaning ovens.

Yttrium oxide, or yttria, has a range of uses including the tough structural ceramic yttria-stabilized zirconia (YSZ) that has many uses including protective coatings on the turbine blades of jet engines, allowing them to run at higher temperatures where they are more efficient. Yttria is the host material for europium and terbium dopants that make red and green phosphors. It is used in dental porcelain and is an essential component in YBa2Cu3O7 high-temperature superconductors. Yttrium is frequently added to metallic alloys to improve their oxidation resistance.

Other uses of rare earths have come and gone over time. Gadolinium gallium garnet single crystals, for example, were used as substrates for permanent memory chips based on the technology of magnetic bubbles in IBM computers of the 1970s and 1980s.

Major new uses for rare earth elements emerged in 1967 with the discovery of high-powered permanent magnets based on samarium and cobalt [4] and again in 1982 with the discovery of even stronger magnets based on neodymium, iron, and boron [5, 6]. Today a large fraction of the permanent magnet market depends on the Nd-Fe-B formulation and its derivatives.

Current uses of the rare earths tend to focus particularly on the properties imparted by their 4f electrons, which are unique to the lanthanides and result in applications related to optical properties, magnetic properties, catalysis, and to some extent mechanical properties. Rare earths are sometimes used to modify the microstructures of major metal products, appearing as grain refiners for castings of aluminum, for example. A partial list of current applications is provided in Table 1.1. In each of these applications, rare earth elements are considered to be difficult or impossible to substitute. Particularly important and persistently unsubstitutable uses for the rare earths include europium, for red light-emitting phosphors, terbium for green light-emitting phosphors, erbium for fiber-optics and medical lasers, and samarium, neodymium, and dysprosium for high-strength permanent magnets. Gadolinium is also important in the control systems of some nuclear reactors, because the uniquely high neutron capture cross section of its nucleus makes it a very effective neutron flux moderator.

Table 1.1

Despite the challenges of maintaining a supply chain for rare earth materials, new potential uses continue to emerge, and a partial list of these is provided in Table 1.2. It is possible or even likely, of course, that many of these technologies will fail to penetrate the market as a result of the usual barriers to commercialization (often characterized as the valley of death), but the challenges are increased in cases where an essential material is known to be critical in the sense described in this book, since this tends to deter interest from investors.

Table 1.2

Rare earth sources

As uses for the rare earths emerged around the beginning of the 20th century, sources for them were developed in a variety of places. From 1900 to about 1960, most of the supplies came from monazite ores in placer deposits, associated with alluvial sand. Monazite is nominally either cerium or lanthanum phosphate, but the cation is actually a mixture of different rare earths, and the anion can also be a mixture of phosphate and silicate ions. The mineral can include thorium in addition to the rare earths. Monazite exists as isolated crystals in igneous rocks such as granite, zircon, or ilmenite, and these crystals are released as grains of sand when the rocks weather. The potential of extracting REEs from monazite was identified by Carl Auer von Welsbach, who discovered it in ballast sand in the bilges of a Brazilian ship, as a source of thorium to provide the material for his lamp mantles. While thorium was the initial target of monazite mining, rare earths such as cerium and lanthanum could be extracted, too. Brazil and India dominated the market for monazite until the outbreak of World War II, when South Africa also began production. Australia and the United States (particularly in North Carolina) have also been producers of this ore from time to time.

New uses for the rare earths that emerged in the years after World War II generated growing demands, and concerns about the radioactivity of thorium created the need to find a different source. A rare earth deposit at Mountain Pass, California, had entered small-scale production in 1952 after being discovered in 1949: this deposit includes both monazite and bastnaesite embedded along with other minerals in a carbonatite matrix. Bastnaesite, bearing rare earths with a much lower thorium content than monazite, became the primary target for rare earth extraction. The Molybdenum Corporation of America, later known as MolyCorp, expanded the production of the bastnaesite ore in the 1960s to meet the growing demand for europium, which was required for the latest consumer electronics sensation—color televisions—and Mountain Pass’s bastnaesite ore body quickly became the world’s dominant source of rare earths.

Bastnaesite is a fluorocarbonate mineral based on the formula (REE)CO3F, where REE refers to any rare earth element. The Mountain Pass bastnaesite’s rare earth content is dominated by cerium and lanthanum, with decreasing amounts of neodymium, praseodymium, samarium, and other elements with higher atomic number, as shown in Fig. 1.3.

Fig. 1.3 Relative concentrations of different rare earth elements contained in the Mountain Pass bastnaesite ore.

In 1977 MolyCorp and its Mountain Pass mine were acquired by Union Oil (Unocal), which became part of Chevron Corporation in 2005. Rare earth demand continued to grow with the development of neodymium-iron-boron permanent magnet alloys in 1982 [5, 6], but the Mountain Pass processing facility was plagued by leaks from its wastewater system, with as many as 60 spills of radioactive waste occurring between 1984 and 1998. In 1984 rare earth production also started at a bastnaesite mine in the Bayan Obo iron mining district near the city of Baotou, Inner Mongolia, in the People’s Republic of China (PRC), and it ramped up very quickly. Production ceased at Mountain Pass in 2002 under the combined pressure of market competition from Baotou and the cost of coping with the challenges of working with hazardous materials in an environmentally sensitive location.

While bastnaesite provided light rare earths such as lanthanum, cerium, praseodymium, and neodymium, it did not meet the demand for heavy rare earths such as europium, dysprosium, and terbium. These are needed in smaller quantities but are crucial in a range of high-tech applications including efficient lighting, where europium is used to generate red light and terbium emits green light. Dysprosium is added to Nd-Fe-B magnets to improve their performance at elevated temperatures. These heavy rare earths, along with a few others, are mostly obtained from deposits of ion-adsorption clays (also known as lateritic clays) that are fairly widespread in Southern China, although the individual deposits are relatively small. The heavy rare earths are extracted by leaching these clay deposits with acid.

By 2008 almost 98% of the world’s rare earth supplies came from China. The output of the leading producers at this time is shown in Fig. 1.4.

Fig. 1.4 The global distribution of rare earth oxide production in 2008. Data from the USGS Mineral Commodity Summary, 2009. https://s3-us-west-2.amazonaws.com/prd-wret/assets/palladium/production/mineral-pubs/mcs/mcs2009.pdf.

Rare earth supply challenges—2005–15

In 2005 the Chinese government began imposing annual export quotas on rare earths and reduced the quotas particularly sharply in 2010, as Chinese domestic industries increased their utilization of these materials. In 2005 the export quota represented about 55% of the total Chinese production, and this proportion fell at an accelerating pace until 2010 when the quota was only 23% of the total production, as shown in Fig. 1.5. The actions taken by China were hard to interpret without a clear view of the operation of Chinese commodity markets, so analysts and pundits in the rest of the world ascribed a variety of agendas or goals to China based on the reported actions, leading to concerns about security of supply and a high degree of market nervousness. One impact of the quotas was a marked differential between the prices of rare earths in China and the rest of the world, and the attention of various governments was drawn to the issue as the prices of imported rare earths began to increase and delivery times lengthened. The price history of the rare earths from the mid-2000s to the mid-2010s is illustrated in Fig. 1.6.

Fig. 1.5 Chinese rare earth oxide production (in green) and export quotas (in red) from 2005 to 2015. The export quotas ended in 2016.

Fig. 1.6 The prices of three representative rare earths from 2006 to 2016. Source of raw price data: Argus Media Inc. (direct.argusmedia.com).

In 2008 rare earth industry authorities including Dudley Kingsnorth [7] projected that China’s internal demand for rare earths would outstrip its own production by about 2012, and total world demand would be met only if production outside of China (the so-called rest of the world or ROW) were to increase substantially.

By this time, concerns about rare earth supplies had already reached high government circles worldwide. Japan is a major importer of rare earths for use in its electronics and electric vehicle industries, and it reacted quickly with government-supported programs to ameliorate potential shortages. Notably a major research and development program to enable recycling of rare metals was started in the summer of 2008, under the banner of Urban Mining [8].

The European Commission recognized the risks posed to the EU’s economy and issued a communication the EU Parliament in November [9].

Following various informal consultations, the US Congress held a formal hearing about rare earth supplies, in the Space, Science and Technology Committee of the House of Representatives in March 2010.

In September 2010 a Chinese fishing vessel collided with a Japanese Coast Guard patrol boat near a group of disputed islands in the East China Sea, known as Senkaku in Japan, and Diaoyu in China. According to China the ship was operating in Chinese waters, but Japan claims the territory, too. The Chinese vessel, its captain, and crew were arrested by the Japanese Coast Guard, resulting in a diplomatic incident between the two nations. While it was widely reported that China cut off rare earth exports to