SoS RARE: Multidisciplinary research towards a secure and environmentally sustainable supply of critical rare earth elements (Nd and HREE)

Lead Research Organisation: University of Leeds
Department Name: School of Earth and Environment


Rare earth elements (REE) have been the headline of the critical metals security of supply agenda. All of the REE were defined as critical by the European Union in 2010 and subsequent analysis by the European Union in 2014, as well as similar projects in the UK and USA, highlighted 'heavy' REE (europium through to lutetium) as the metals most likely to be, not only at risk of supply disruption, but in short supply in the near future. The challenge is to find and produce the most environmentally friendly, economically viable, neodymium (Nd) and HREE deposits so that use of REE in new and green technologies can continue to expand.

The principal aims of this project are to understand the mobility and concentration of Nd and HREE in natural systems and to investigate new processes that will lower the environmental impact of REE extraction and recovery.

By concentrating on the critical REE, the research programme can be wide ranging in the deposits and processing techniques considered. It gives NERC a world-leading research consortium on critical rare earths, concentrating on deposit types identified in the catalyst phase as most likely to have low environmental impact when in production, and on research that bridges the two goals of the grant call.

The project brings together two groups from the preceding catalyst projects (GEM-CRE, MM-FREE) to form a new interdisciplinary team consisting of the UK's leading experts in the geology of REE deposits, who bring substantial background IP and recent studies, together with key scientists from materials science, high and low temperature fluid geochemistry, computational simulation and mineral physics, geomicrobiology and bioprocessing. The research responds to the needs of collaborative industry partners and involves substantive international collaboration as well as a wider international and UK network across the REE value chain.

The work programme has two strands. The first centres on conventional deposits, which comprise all of the REE mines outside China and the majority of active exploration and development projects. The aim is to make a step change in the understanding of the mobility of REE in these natural deposits. Then, based on this research, further mineralogical analysis and computational and experimental studies, the aim is to optimise the most relevant extraction methods. The second strand looks further to the future to develop a sustainable new method of REE extraction. The focus will be the ion adsorption deposits, from which it is easy to leach Nd and HREE and which could be exploited with the lowest environmental impact of any of the main ore types using a well-controlled in-situ leaching operation.

Application will be immediate through our collaboration with industry partners engaged in REE exploration and development projects, who will gain improved deposit models and better and more efficient, and therefore more environmentally friendly, extraction techniques. There will be wider benefits as we publish our results for researchers in other international teams and companies to use. Diversity and security of REE supply are very much an international issues and the challenges tackled in this research are common to practically all REE deposits. Even though the UK does not have world class REE deposits itself and is reliant on overseas projects, there is an excellent opportunity to provide world-leading expertise for this development. Manufacturers who use REE will also benefit from the research results by receiving up to date information on prospects for future Nd and HREE supply. This will help plan their longer term product development, as well as shorter term purchasing strategy. Likewise, the results will be useful to inform national and European level policy making and to interest, entertain and educate the wider community about the natural characters and importance of the REE.

Planned Impact

SoS RARE research results will have immediate impact to improve prospects for security of supply of neodymium (Nd) and the key heavy rare earth elements (HREE) required for environmental technologies. The project has 6 core industry partners involved in exploration and development projects to open new mines who will benefit immediately from new exploration models and improved techniques for mineral extraction that will make their projects more economic and environmentally friendly. There are also four consultant company partners who will gain key expertise and experience in exploration and processing so that they can expand their business.

There will also be important impacts on manufacturers who use the REE, both for their near term supply prospects and longer term product planning. These impact will be in the form of information from the research team on prospects for additional primary supplies , and their nature, and later, via improved security of supply as additional primary suppliers come into the market, benefitting from the technical research outputs.

REE supply is very much a global concern, being near the market is not a main issue for such specialist metals and prospects for REE in the UK are poor. The project will have global reach, through the industry partners involved (based and work in UK, Greenland, Malawi, Namibia, Spain, Australia) , the core collaborators in Germany, USA, Canada, Brazil and South Africa and wider international network links to Japan, France, Madagascar . Diversity of supply is the key. This research ensures that UK expertise is involved at the forefront of critical metals development.

The issue of critical metals has required changes in UK Government and European Union policy, including increased support for research ion primary supplies, recycling of existing metal stocks and substitution. The research outcomes from this project regarding prospects for low environmental impact extraction of REE, diversity and security of supply and responsible sourcing will be directly relevant to future policy. The 'race' to engineer REE out of new technologies is unnecessary once supplies are secure. Security of supply would enable UK and European industry to take advantage of the many important properties of REE in new technologies.

Few people had even heard of 'rare earths' until the issue of China restricting supply reached the news headlines in 2010. This rare earth family of elements are however ubiquitous in digital and green technologies, from the slimmest mobile phones to giant wind turbines. . REE can be fun, 17 elements with distinct characters, ideal for creative and educational outputs to entertain and inform wider non-technical audiences. Encouraging the public, including school students, to learn more about REE in nature is a key part outreach programme.


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NE/M011232/1 20/05/2015 30/03/2016 £531,476
NE/M011232/2 Transfer NE/M011232/1 31/03/2016 30/11/2019 £461,095
Description Experimental work on a joint PhD project with the mining industry has provided data sets on the ion exchange reactions of Rare Earth Elements (REEs) that can be extracted from ion exchange clay deposits as an Earth surface mining environment. The data sets have provided initial estimates of thermodynamic constants for the ion exchange reactions at chemical equilibrium with water solutions. Additional data sets from laboratory column experiments demonstrated the rate of flushing of REEs from ion exchange clay soils when flushed with water solutions containing high concentrations of calcium ions. The data sets provide parameter values for computer modelling of the reactive transport of REEs in mining environment which will allow hypothesis testing on potentially more environmentally-friendly mining methods that reduce chemical pollution during REEs extraction from ion exchange clay deposits.

1. Mobilisation of Rare Earth Elements (REE) from laterite soils to solution is explained by stoichemtric ion exchange reactions of REEs with BaCl2 salt solutions.
2. The reactions achieve apparent thermodynamic equilibrium within 48 hours when soil particles react with an ionic solution of BaCL2,
3. The apparent thermodynamic constant for ion exchange of REES is nearly identifcal for all REES suggesting a non-specific ion adsorpton..
4. The single thermodynamic constant is able to explain the breakthrough curve of REEs and base cations when flushing laboratory column reactors containing soil with BaCl2 solutions

Further column experiments investigated the extraction of REEs from an ion-adsorption clay from Madagascar using a high ionic strength aqueous salt solution, chosen based on experimental evidence to maximise REE extraction and minimise undesirable dissolved Al in column effluent. Lower Al concentration in eluted solution reduces its interference with subsequent processing steps that use ammonium oxalaste to precipitate and concentrations REEs in the extraction process. We show that the selected salt solutions can be used to efficiently extract REE with relatively low solution volumes in a through-flow column reactor at bench scale. We show that when extraction with a pulse of salt solution is followed by a rinsing step of dilute solution, there are several identifiable stages during the extraction process, including a marked increase in total lanthanides extracted, which is correlated with the breakthrough of ammonium ions, and where the eluted dissolved Al concentration decreases from its peak concentration.
Exploitation Route The data sets and parameter values for computer modelling of REE reactive transport will be of use to the mining industry to explore potentially improved methods of extracting REEs in ion exchange deposits. The thermodynamic data will be used in geochemical thermodynamic data sets for modelling of REEs in the environment.

The results are included in a submitted peer-reviewed academic journal.
Sectors Environment,Manufacturing, including Industrial Biotechology,Other

Description The research has informed the industry partner's expertise and knowledge base on Rare Earth Element mining methods; but has not yet to date been applied at a mining site.
First Year Of Impact 2017
Sector Environment,Other
Impact Types Economic

Description joint PhD project with the mining industry 
Organisation Umwelt- und Ingenieurtechnik GmbH
Country Germany 
Sector Private 
PI Contribution We provide 50% of a NERC industry studentship and are primary academic supervisors to support this industry PhD project
Collaborator Contribution The company provides 50% of an industry studentship as a cash contribution and hosted the student for 18 months providing laboratory facilities and day-to-day supervision of research
Impact Experimental work at the company have provided data sets on the ion exchange reactions of Rare Earth Elements (REEs) that can be extracted from ion exchange clay deposits. The data sets have provided estimates of thermodynamic constants for the ion exchange reactions at chemical equilibrium with water solutions. Additional data sets from laboratory column experiments demonstrated the rate of flushing of REEs from ion exchange clay soils when flushed with water solutions containing high concentrations of calcium ions. These data sets contribute to a new manuscript that is submitted for publication.
Start Year 2016