There is a move towards global decarbonisation to tackle climate change, which will lead to increased demand for a range of REEs in the coming decades. As resources of primary REEs are finite and global supply is highly dependent on China, adopting circular strategies, including re-use and recycling, may improve the security of supply of REEs for countries like the UK and alleviate pressure on primary supply.

Products with embedded REEs

REEs play an important role in green and clean energy technologies, including wind turbines, electric vehicles, fuel cells and lighting. Many REEs (for example, Nd, Dy, Pr, Tb) are used in the production of 'NdFeB' (neodymium-iron-boron) magnets. Figure 7 shows the end-use share of NdFeB magnets. These magnets, which are embedded in REE-bearing products, have different lifespans:

• two to three years in consumer electronics
• nine to thirteen years in electric vehicles
• 25 to 35 years in wind turbines

Electric vehicle sales and wind turbine installations have been increasing in the UK during the past few years. Both, therefore, have a high potential of becoming future secondary sources of supply of certain REEs such as Nd, Dy, Pr, Tb. The availability of secondary sources of REEs depends on several factors, including historical production, product lifespan, collection rates and the yields of recycling. When REE-bearing products enter the end-of-life stage, there are many opportunities to retain the highest-value REEs within the UK economy.

Current situation and challenges

Potential secondary sources of REEs include industry by-products, waste water and end-of-life products. Of these, the end-of-life products have the greatest potential for secondary supply. Since the mid-1980s, NdFeB magnets have been manufactured and widely used, for example in hard disk drives and electric motors. Considering product lifespan, there are already opportunities to recycle the REEs within NdFeB magnets as a secondary supply. However, only 1 per cent of REEs are recovered and less than 1 per cent of NdFeB magnets are recycled.

The main destinations of REE-bearing waste are exports to other countries, landfill sites and loss as contaminants in various waste streams (Figure 2). REEs are technically and economically difficult to collect and recycle because of:

• small quantities of REEs in many applications
• complexity of products
• lack of support for developing novel segregation
• scaling up the recycling processes

In the future, there will be opportunities to recycle REEs from electric vehicles and wind turbines, so it is important to monitor REE flows across the life cycle stages at different levels (substances; components; products) as well as to develop end-of-life management to improve REE supply circularity.

In the near future, there will be rapidly growing demand for REEs but secondary REEs are unlikely to overtake primary supply in the short term. In the long term, developing recycling technologies and infrastructure could contribute to tackling the criticality of REEs. Stock modelling can show the potential quantities available for recycling and highlight the need for future recycling capacity.

Recycling technologies and circular strategies

REEs are considered critical mineral resources, therefore several government interventions are needed to support both their primary and secondary supplies. In terms of secondary sources, financial investment is needed in research and development focused on resource efficiency, separation and recycling technologies, as well as infrastructure for the collection and recycling of REE-bearing products.

Collaboration, both globally and domestically, is key to creating diverse primary and secondary REE markets and resilience of both primary and secondary supplies. For example, the Rare Earth Industry Association (REIA) and the European Raw Materials Alliance (ERMA) gather togther REE stakeholders to exchange data, information and knowledge related to REEs. Traceability is particularly significant for creating a circular economy system of REEs. It is important for governments, academia and industry stakeholders across the REE value chain to collaborate in developing a circular economy system and improve the traceability and transparency of REEs.

Education includes training the next generation of skilled workers across the REE value chain, with a focus on the circular economy, whilst educational campaigns for consumers can improve understanding of the social and environmental effects of REEs. Education has the potential to drive social behaviour change to circular use and recycling of REE-bearing products, especially for consumer electronics and electric mobility.

Regulatory intervention can be more powerful in supporting the secondary supply of REEs. The extended producer responsibility (EPR) scheme can enhance not only the producers' responsibility for end-of-life-product management, but also the product design for disassembly, re-use, repair and recycling. Further regulatory issues such as taxes, international trade laws, standardisation, investment and environmental regulations are discussed on the legal and regulatory page.

Background geological information and challenges

There are many documented occurrences of REE-bearing minerals in the UK, including:

• allanite
• chevkinite
• fergusonite
• gadolinite
• monazite
• synchysite

However, in most cases, these occurrences comprise only minor, low-tenor REE enrichment over restricted areas. For example, many of these minerals are found as rare accessory phases in some Tertiary granites or are minor accessories to lead-zinc-fluorite mineralisation in the Northern Pennine Orefield (Walters and Lusty, 2011). To date, there has been no mine production of REE-bearing minerals in the UK, nor are there any deposits in which REE reserves or resources have been reported.

There has only been very limited evaluation of the REE potential in the UK. During the early 1990s, BGS made a preliminary assessment of the REE contents of three late-Caledonian, alkaline intrusive complexes in north-west Scotland. Rock and drainage samples from Loch Borralan, Loch Ailsh and Loch Loyal were analysed for cerium, lanthanum and yttrium (Shaw and Gunn, 1993). BGS also undertook an assessment of the economic potential of mudstone-hosted nodular monazite in south-central Wales during this period (Smith et al., 1994). More recently, a BGS-hosted MSc student reappraised drill core from the ultramafic section of the Loch Borralan complex to further assess its potential as an REE resource (Griffith, 2011) and, in 2013, BGS studied the formation of late-stage, allanite-bearing veins associated with the Loch Loyal syenite complex (Hughes et al., 2013; Walters et al., 2013).

A priority target for further investigation is the Cnoc nan Cuilean Intrusion in north-west Scotland. The hydrothermal, allanite-bearing veins that cross-cut the intrusion contain the highest REE grades recorded in the UK (up to 2 wt% TREO) (Walters et al., 2013). The known occurrence of significant hydrothermal, REE-mineralised veins associated with alkaline igneous rocks elsewhere in the world provides a strong basis for evaluating this area further. However, there is currently no commercial process for extracting REEs from allanite; this, coupled with the thin and discontinuous nature of the veins, makes them unlikely to be economic.

It is also important to note that previous work by BGS on the Caledonian alkaline intrusions of north-west Scotland has focused on the platinum group metal potential of six selected parts of these bodies. Systematic investigations over the entirety of these complex intrusions are recommended in order to fully evaluate their REE potential.

UK critical minerals strategy and market opportunities

A recent UK criticality assessment published by BGS, commissioned by BEIS (now DBT), shows REEs high on the list. The security of a rare-earth material supply is crucial to the UK's electrification ambitions, which are required to meet the UK Government's net zero target. The UK's Critical Minerals Strategy, announced in 2022, aims to accelerate the growth of the UK's domestic capabilities, collaborate with international partners and enhance international markets to make them more responsive, transparent and responsible. There are significant opportunities for the UK to deploy its expertise and forefront research assets for innovation in these areas and establish REE market share.

To build up the sustainable supply chain of REEs in the UK, the UK would need to diversify its supply of REEs and explore the possibility of mining and refining ores into metals and alloys. The UK has a leading role in research and development, education of metal refining and green chemistry. It is therefore important to use this strength to develop new innovations for the chemical treatment and separation of REEs. Furthermore, there are many UK-based original equipment manufacturers; it is also suggested that incentives are provided for them to develop magnet production and its end-of-life management.

Recycling of REE-containing magnets and products for secondary supply

The UK will need to secure significant quantities of REEs to achieve the electrification transition. There are supply risks and limits for domestic primary production. It is therefore crucial to develop a long-term ecosystem for secondary supply. The current in-use stocks could provide buffer capacity if circular economy systems are established. In the future, assuming that the net-zero targets materialise, the UK stock in products could create viable circular economy business opportunities.

As most of the current plants are still at the pilot scale, it is necessary to assess the technology readiness levels (TRLs) of the UK's existing REE recovering technologies. The UK has expertise and capability in material science and REE recycling; for example, the University of Birmingham has strong research expertise in recovering REE. Investing in research and development and establishing a secondary supply chain could expand the REE recycling capacity of the UK and stimulate further innovation in magnets, especially research into next-generation magnet materials.