wwwtechnologymattheycom JOHNSON MATTHEY TECHNOLOGY REVIEW

httpdxdoiorg101595205651317X694759 Johnson Matthey Technol Rev 2017 61 (2) 126ndash132

Materials Challenges for a Transforming World Developments for a sustainable future the example of rare earths

By Richard Miller Miller-Klein Associates Ltd Saith Ffynnon Downing Road Whitford Flintshire CH8 9EN UK

Email richardmiller-kleincom

The solutions being developed for a sustainable future are technologically complex and demanding relying on lsquohigh-techrsquo raw materials Many of these materials face significant supply risk Business government national and international organisations are increasingly focusing on these critical raw materials (CRMs) This paper describes the strategies and innovations being developed to manage supply risk using rare earth elements and magnets as examples The ongoing need to find substitute materials and improve efficiency recycling and recovery of CRMs provides exciting opportunities for fundamental research and commercial innovation

Introduction

The world is undergoing transformational change John Beddington a previous Chief Scientific Adviser to the UK Government wrote about a lsquoPerfect Stormrsquo of population growth climate change and resource crunches that would require radical changes for a sustainable future (1) These factors interact in complex ways The population is not only growing it is rapidly urbanising increasing the pressure on city infrastructures climate change will drive migration that will be a further challenge for cities Climate change

is not only a threat to food production but directly endangers global cities through rising sea levels and temperatures Resource challenges range from the obvious food water and land to subtler issues such as the energy and materials we use to build our societies

These challenges have a direct impact on national and global economies The gross value added (GVA) for the UK economy is about pound17 trillion per annum About pound500 billion per annum of that will be delivered in a very different way in the future in sectors such as energy transport food construction and healthcare (2) It is not known what new products services and business models will appear but they will be different Business as usual is simply not viable in order to meet the United Nations (UN) Sustainable Development Goals (3) and their local implementations Over the coming years thousands of innovations will appear and some of these will come to replace current solutions that will no longer be appropriate Innovations will be forced to balance the needs of people planet and profit

Increasing Dependence on lsquoHigh Techrsquo Raw Materials

Many of the solutions currently being developed depend heavily on electrical electronic computing and communications technologies These in turn rely on the sophisticated use of specific lsquohigh-techrsquo raw materials many of them only currently available in limited quantities Finite supply leads to concerns about security of supply and price Prices for many of these key materials have risen significantly in recent years and perhaps more importantly for business have shown notable volatility (4 5) Figure 1 shows

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4500 Fig 1 Relative changes in rare earth oxide prices over4000 time (4 5)

Perc

enta

ge c

hang

e in

pric

e re

lativ

e to

200

7

3500

3000

2500

2000

1500

1000

500

0

ndash500

Lanthanum Cerium Praseodymium Neodymium Samarium Europium Gadolinium Terbium

Dysprosium Yttrium

2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

how supply constraints in rare earth oxides can cause prices to suddenly spike 30ndash40 fold

To give a simple example of this complexity a modern smart phone contains at least 70 out of the 83 naturally stable elements in the periodic table (6) They use almost the complete palette Figure 2 shows where some of the key elements are used (7)

The recognition of the importance of these CRMs has focused businesses governments and national and international organisations on their source and flows Many governments have published lists of the materials they consider of most importance to their economy and where there are significant risks to supply security (8) Supply risks have been explored by the European Union (EU) (9) the USA (10) and Japan (11) These lists are predominantly populated by materials used in the electrical and electronics industry in catalysts and alloys

For example the EU lists 20 CRMs Three of the CRMs are groups of closely related materials platinum group metals light rare earths and heavy rare earths (9) Of the 20 CRMs identified by the EU seven are mainly used in electrical and electronic equipment including the groups of rare earths and seven are used in the production of metallic alloys

Different authorities use slightly different methods to assess the supply risk for each CRM but common factors taken into account are bull Concentration of primary supply ndash how many countries are significant suppliers

bull Reserve distribution ndash how widely distributed are proven reserves

bull Political stability of suppliers ndash what is the risk of disruption of primary production

bull Companion fraction ndash how much is produced as a side stream from a bulk material and therefore dependent on the economics of the primary product

bull Substitutability ndash are alternatives available for the key applications

bull Recyclability ndash can it be recycled at end of life and is it being recycled

One factor that might appear impor tant that is not usually assessed is the absolute crustal abundance of the material This is rarely a defining feature of the availability and economics and supply security of a CRM The British Geological Survey UK publishes a

regularly updated risk list of economically important elements (12) Their current list of 41 elements range

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Au AlDiam

ond

U Ni Sn Cr F Ta

Graphit

ePGE As Co Sr Ge Bi Sb

REE

httpdxdoiorg101595205651317X694759 Johnson Matthey Technol Rev 2017 61 (2)

Fig 2 Use of CRMs in smartphones (7) (copy Compound Interest)

in supply risk from the rare earth elements at the top to gold at the bottom with the platinum group metals somewhere in the middle An extract of some of the key materials and their risk scores is given in Figure 3

The rare earth elements are at the top because China produces 96 of global supplies and controls 42 of known reserves More than two-thirds is produced as a co-product from other economically important materials Rare earth elements are hard to substitute and poorly recycled

This adds up to a considerable supply risk and given the criticality of rare earth elements to the drive for a

low-carbon and efficient global economy there is much government interest in these specific materials

Strategies to Manage Supply Risk

Governments have responded by raising awareness of the challenge and encouraging innovation There is a huge amount of effort in gathering and disseminating information about CRMs bringing together industry players to collaborate and sponsoring industry and academic research to develop new solutions The EU Japan and the USA have held tri-lateral workshops to

45 48 52 55 57 6 62 69 71 74 76 79 81 83 86 88 9 95

Fig 3 Supply risk for some materials critical to the UK economy (12)

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promote sharing of knowledge and approaches to risk mitigation (13)

Government-industry initiatives that have been set up to address supply risk in CRMs include bull Critical Materials Institute USA (14) bull Advanced Research Projects Agency-Energy

(ARPA-E) Rare Earth Alternatives in Critical Technologies (REACT) USA (15)

bull European Institute of Innovation and Technology (EIT) RawMaterials EU (16)

bull National Institute of Materials Science Japan (17) The broad strategies for addressing CRM risk are

simple The upstream option is to improve primary production by increasing the reserves that are available to exploit and the efficiency of extraction while decreasing the costs and overall environmental impact In the case of the rare earth elements this is hard to achieve The concentration of production and proven reserves in China make it difficult for any other player to materially shift the balance and the materials security risk remains high

Moving downstream there are more opportunities to improve security and reduce costs As with any problem material the main options are bull substitution ndash find an alternative material with a

lower supply risk bull efficiency ndash get more of the desired effect out of

less material bull reuse and recycling ndash having expensively and with difficulty obtained the CRM keep it above ground and circulating productively for as long as possible

One of the key tasks being undertaken by the academic world is mapping the stocks and flows of critical raw materials in the global economy A leading light in this work for many years has been Graedel (18) His meticulous work in industrial ecology has unravelled much of the detail of what happens to industrially important materials through their life cycle and laid the foundation for both government policy and commercial action Knowing what is actually happening in a complex system is a key step in deciding what action to take to shift it to a more stable position

Innovation in Rare Earth Magnets

There is a great deal of research and innovation targeting the CRMs with the greatest materials security risk far too much to offer a comprehensive analysis here But it is possible to illustrate some of the recent approaches using examples from rare earth magnets

These are used for everything from wind-power generation through electric cars to computer hard drives and smartphones Current generation wind turbines use about 500 kg MWndash1 (19) an electric car uses 25 kg for the electric motor and an electric bike uses 80 g (20) A smartphone (21) uses much less than a gram

The rare earth elements used have the highest supply risk (12) and it can be predicted that current technological solutions for a sustainable economy will dramatically increase their use The ratio in which the different rare ear th elements are produced is not the same as the market demand This leads to a supply balance problem which is proving difficult to manage (22) In neodymium-iron-boron (NdFeB) magnets some of

the neodymium is replaced by dysprosium to enable the magnets to perform at high temperatures Unfortunately the low ratio of dysprosium to neodymium in primary extraction and low levels of recycling mean that there is a structural shortage of dysprosium available for these applications The obvious solution is to find a substitute for the dysprosium and despite the general difficulty of finding alternatives for rare earth elements there has been progress

For example one approach has been to reduce the grain size in sintered NdFeB magnets from a typical 5ndash10 μm to around 80 nm Movement of the magnetic domains is reduced by the larger number of grain boundaries increasing the thermal stability (23) This has allowed the demonstration of magnets suitable for traction motors without adding any dysprosium

Another discovery recently reported by Oak Ridge National Laboratory USA was that dysprosium could be replaced with cerium co-doped with cobalt (24) Since cerium is the most common rare earth element and dysprosium one of the scarcest there is potential to reduce the cost of high performance NdFeB magnets by 20ndash40 Cerium on its own does not work as it reduces the temperature at which the magnetism is lost but the new alloy with cobalt maintains its performance to temperatures higher than dysprosium doped magnets

Work is also going on to reduce the amount of rare earth elements needed to produce a magnet with the required performance Improvements in recipes and alloys are always being sought but recently there has also been research on using three-dimensional (3D) printing to create precise magnet forms with minimal material A magnet can be designed by computer modelling to

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provide the precise field strength and distribution using as little magnetic material as possible 3D printing can then produce these forms with negligible waste Suess and colleagues have shown this approach for polymer bonded magnets (25) as have a team from Oak Ridge National Laboratory and the Ames Laboratory USA (26) A collaboration between Oak Ridge National Laboratory and Arnold Magnetic Technologies USA demonstrated that it was possible to use laser heating to produce near net form sintered magnets (27) although with diminished performance

Further development towards commercial production of rare earth magnets can be expected using a variety of additive layer manufacturing techniques

At present the potential for reuse and recycling of rare earth magnets depends on the application and the size of the magnets At one extreme the large magnets used in wind turbines (~500 kg MWndash1) are in a known location and will be subjected to controlled deconstruction at their end-of-life At the other extreme mobile phones and other small consumer electronics carry small magnets and are distributed thinly across the sur face of the globe Wind turbine magnets are a valuable resource and are reused or recycled but less than 1 of the rare earth elements from consumer electronics are captured and recycled (28)

There are a number of processes for recycling rare earth magnets (28) varying in cost efficiency and environmental risk One of the most interesting is hydrogen decrepitation where hydrogen gas is used to break down the magnets into a fine powder that can be re-sintered into new magnets (29) The key attraction of the process is that the magnets do not have to be mechanically separated before recycling So in applications like hard disk drives time consuming disassembly steps can be avoided

A different approach has been taken by Oak Ridge National Laboratory who have developed an automated disassembly method for hard disk drives (30) This uses a library of hard disk configurations and advanced robotics to correctly orient and locate the drives for robotic disassembly It is estimated that 1000 tonnes of rare earth magnets could be recovered in the USA and reused remanufactured or recycled The system has now been licensed for commercial trials

The researchers hope to extend the work to consumer electronics such as smart phones However the diversity of designs and the lack of any system for recovering phones at end-of-life will be a problem

If a circular economy in rare earth elements is to be made possible products need to be designed for reuse and recycling and business models need to allow the efficient recovery of consumer products containing CRMs Improved methods to recover CRMs are of little use if there is no stream of consumer products to process

Conclusions

The only currently workable route to a sustainable global economy that balances economic viability environmental responsibility and social acceptability requires wide deployment of a whole range of advanced technologies These in turn depend on the availability of CRMs that face challenges of security of supply and of price volatility

Governments in industrialised countries will continue to encourage academia and industry to come up with ways to mitigate the CRM risks and industry will persist in seeking solutions that can be commercialised This interest and focus is unlikely to be substantially reduced by any temporary change in market conditions Until the supply risks can be drastically and permanently lessened there will always be pressures to make more effective use of the CRMs Radical new technologies that do not use current CRMs and that do not replace them with alternatives that are equally risky could change the picture completely but none are visible on the horizon and it would be many years before they could have a significant impact

This means there will be exciting opportunities for both fundamental research and commercial innovation in substituting using more efficiently and recycling CRMs Opportunities in everything from fundamental chemistry and materials science to the design and production engineering of consumer products

References 1 J Beddington lsquoFood Energy Water and the Climate

A Perfect Storm of Global Eventsrsquo Sustainable Development UK Annual Conference QEII Conference Centre London UK 19th March 2009

2 lsquoUK Non-financial Business Economy Sections A to S (Part)rsquo in ldquoAnnual Business Survey UK Non-financial Business Economy 2015 Provisional Resultsrdquo Statistical bulletin Office for National Statistics South Wales UK 2016

3 United Nations Sustainable Development Knowledge

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Platform Sustainable Development Goals https sustainabledevelopmentunorgsdgs (Accessed on 4th January 2017)

4 Arafura Resources Ltd Pricing httpwwwarultdcom rare-earthspricinghtml (Accessed on 20th August 2014)

5 J Gambogi ldquo2014 Minerals Yearbook Rare Earthsrdquo US Geological Survey Virginia USA 2016

6 B Rohrig lsquoSmart Phones Smart Chemistryrsquo ChemMatters April 2015 p 10

7 A Brunning lsquoThe Chemical Elements of a Smartphonersquo Compound Interest Cambridge UK 2014

8 E Bartekovaacute and R Kemp ldquoCritical Raw Material Strategies in Different World Regionsrdquo The United Nations University ndash Maastricht Economic and Social Research Institute on Innovation and Technology (UNU-MERIT) Working Papers 2016-005 Maastricht University The Netherlands 2016

9 European Commission lsquoReport on Critical Raw Materials for the EU Critical Raw Materials Profilesrsquo Ref Ares(2015)3396873 Brussels Belgium 14th August 2015

10 R Silberglitt J T Bartis B G Chow D L An and K Brady ldquoCritical Materials Present Danger to US Manufacturingrdquo RAND Corp California USA 2013

11 H Kawamoto Sci Technol Trend Quart Rev 2008 27 (04) 57

12 MineralsUK lsquoRisk List 2015rsquo British Geological Survey Centre for Sustainable Mineral Development Nottingham UK 2015

13 European Commission Directorate-General Enterprise and Industry Directorate F Resources Based Manufacturing and Consumer Goods Industries lsquoUS-Japan-EU Trilateral Workshop on Critical Raw Materials Workshop ReportMinutesrsquo Ref Ares(2014)2187791 Brussels Belgium 2nd December 2013

14 The Ames Laboratory US Department of Energy Critical Materials Institute httpcmiameslabgov (Accessed on 27th January 2017)

15 Advanced Research Projects Agency-Energy (ARPA-E) lsquoREACT Program Overviewrsquo ARPA-E Washington DC USA 2011

16 EIT RawMaterials httpseitrawmaterialseu (Accessed on 27th January 2017)

17 National Institute of Materials Science httpwww nimsgojpeng (Accessed on 27th January 2017)

18 T E Graedel E M Harper N T Nassar and B K Reck Proc Nat Acad Sci 2015 112 (20) 6295

19 L G Marshall lsquoClean Energy Runs on Magnetsrsquo Minor Metals Trade Association London UK 2016

20 S Constantinides lsquoThe Demand for Rare Earth Materials in Permanent Magnetsrsquo 51st Annual Conference of Metallurgists Niagara Falls USA 30th Septemberndash3rd October 2012

21 M Buchert A Manhart D Bleher and D Pingel ldquoRecycling Critical Raw Materials from Waste Electronic Equipmentrdquo Oeko-Institut eV Darmstadt Germany 2012

22K Binnemans P T Jones K Van Acker B Blanpain B Mishra and D Apelian J Met 2013 65 (7) 846

23 N Sheth lsquoDysprosium-Free Rare Earth Magnets for High Temperature Applicationsrsquo Magnetics Business amp Technology March 2013

24 A K Pathak M Khan K A Gschneidner Jr R W McCallum L Zhou K Sun K W Dennis C Zhou F E Pinkerton M J Kramer and V K Pecharsky Adv Mater 2015 27 (16) 2663

25 C Huber C Abert F Bruckner M Groenefeld O Muthsam S Schuschnigg K Sirak R Thanhoffer I Teliban C Vogler R Windl and D Suess Appl Phys Lett 2016 109 (16) 162401

26 L Li A Tirado I C Nlebedim O Rios B Post V Kunc R R Lowden E Lara-Curzio R Fredette J Ormerod T A Lograsso and M Parans Paranthaman Sci Rep 2016 6 36212

27 M Parans Paranthaman N Sridharan F A List S S Babu R R Dehoff and S Constantinides lsquoAdditive Manufacturing of Near-net Shaped Permanent Magnetsrsquo ORNLTM-2016340 Oak Ridge National Laboratory Oak Ridge Tennessee USA 2016

28 K Binnemans P T Jones B Blanpain T Van Gerven Y Yang A Walton and M Buchert J Clean Prod 2013 51 1

29 A Walton H Yi N A Rowson J D Speight V S J Mann R S Sheridan A Bradshaw I R Harris and A J Williams J Clean Prod 2015 104 236

30 S G Seay lsquoORNL Licenses Rare Earth Magnet Recycling Processrsquo Materials Science Phys Org 2nd September 2016

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The Author

Trained as a chemist Richard Miller has spent over 30 years in industrial research and development and 23 years working on sustainability and resource efficiency He has been a Research Director in fast moving consumer goods and chemicals companies worked with public agencies to support industrial innovation and currently runs a consultancy