Rare earth elements (REE) are the headline of the critical metals security of supply agenda. All the REE were defined as critical by the European Union in 2010, and in subsequent analysis in 2014. Similar projects in the UK and USA have highlighted 'heavy' REE (HREE - europium through to lutetium) as the metals most likely to be at risk of supply disruption and in short supply in the near future. The REE are ubiquitous within modern technologies, including computers and low energy lighting, energy storage devices, large wind turbines and smart materials, making their supply vital to UK society. The challenge is to develop new environmentally friendly and 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 will be wide ranging in the deposits and processing techniques considered. It gives NERC and the UK a world-leading research consortium on critical REE, concentrating on deposit types identified in the catalyst phase as most likely to have low environmental impact, and on research that bridges the two goals of the SoS programme. The project brings together two groups from the preceding catalyst projects (GEM-CRE, MM-FREE) to form a new interdisciplinary team, including the UK's leading experts in REE geology and metallurgy, together with materials science, high/low temperature fluid geochemistry, computational simulation/mineral physics, geomicrobiology and bioprocessing. The team brings substantial background IP and the key skills required. The research responds to the needs of 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 via mineralogical analysis, experiments and computational simulation. Then, based on this research, the aim is to optimise the most relevant extraction methods. The second strand looks to the future to develop a sustainable new method of REE extraction. The focus will be the ion adsorption deposits, which could be exploited with the lowest environmental impact of any of the main ore types using a well-controlled in-situ leaching operation. Impact will be immediate through our 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 for researchers in other international teams and companies as we publish our results. Security of REE supply is a major international issue and the challenges tackled in this research will be relevant to practically all REE deposits. Despite the UK not having world class REE deposits itself, the economy is reliant on REE (e.g. the functional materials and devices industry is worth ~£3 Bn p.a.) and therefore the UK must lead research into the extraction process. Manufacturers who use REE will also benefit from the research 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 and to interest, entertain and educate the wider community about the natural characters and importance of the REE.

Rare Earth Elements (REE) are used in many low carbon technologies, ranging from low energy lighting to permanent magnets in large wind turbines and hybrid cars. They are almost ubiquitous: in every smartphone and computer. Yet 97% of World supply comes from a few localities in China. Rare earth prices are volatile and subject to political control, and but substitute materials are difficult to design. The most problematic REEs to source are neodymium and the higher atomic number 'heavy' rare earths - a group dubbed the 'critical rare earths'. However, with many potential rare earth ore deposits in a wide variety of rocks, there is no underlying reason why rare earths should not be readily and relatively cheaply available. The challenge is to find and extract rare earths from the right locations in the most environmentally friendly, cost efficient manner to give a secure, reasonably priced, responsibly sourced supply. In this project, the UK's geological research experts in rare earth ore deposits team up with leaders in (a) geological fluid compositions and modelling, (b) using fundamental physics and chemistry of minerals to model processes from first principles and (c) materials engineering expertise in extractive metallurgy. This community brings expertise in carbonatites and alkaline rocks, some of the Earth's most extreme rock compositions, which comprise the majority of active exploration projects. The UK has a wealth of experience of study of economic deposits of rare earths (including the World's largest deposit at Bayan Obo in China) which will be harnessed. The team identify that a key issue is to understand the conditions that concentrate heavy rare earths but create deposits free from thorium and uranium that create radioactive tailings. Results so far from alkaline rocks and carbonatites are contradictory. A workshop will bring together the project team and partners, including a leading Canadian researcher on rare earth mobility, to debate the results and design experiments and modelling that can be done in the UK to solve this problem. Understanding, and then emulating how REE deposits form, may provide us with the best clues to extract REEs from their ores. One important route is to understand the clay-rich deposits in China which provide most of the World's heavy rare earths; they are simple to mine, not radioactive, and need little energy to process. The workshop will consider how these deposits form, how we can use our experimental and modelling expertise to understand them better and predict where companies should explore for them. The other main problem, restricting development of almost all rare earth projects, is the difficulty of efficient separation of rare earth ore minerals from each other and then extraction of the elements from those ores. A work shop on geometallurgy (linking geology through mining, processing, extractive metallurgy and behaviour in the environment) will be used to explore how geological knowledge can be used (a) to predict the processing and environmental characteristics of different types of ores and (b) to see if any new potential processing methods might be tried, taking advantage of fundamental mineralogical properties. The two workshops link geology to metallurgy, using one to inform the other. This project will form the basis for an international collaborative consortium bid to NERC. It will also catalyse a long-term UK multidisciplinary network linking rare earth researchers to users, and promote the profile of the UK in this world-wide important field. Before the team design the research programme, they will consult academic colleagues working on new applications of rare earths and rare earth recycling, plus exploration companies, users further along the up the supply chain and policy makers. This will ensure that the proposals developed have maximum impact on future supply chain security.

Having historically disposed of vast quantities of industrial, municipal, metallurgical and mining waste into the ground, societies have put into geological storage an enormous amount of resources in a range of materials of value such as metals and energy (in the form of biomass and polymers). Therefore, instead of considering these waste repositories to be a legacy waste issue and a long-term liability, a paradigm shift is required to view these installations as "resource hubs" for future recovery. The proposed research aims to contribute towards the development of a new and exciting research field related to resource recovery from existing waste repositories and seeks to address the following central question: Can resources, specifically elements of value (e.g. Au, Pd, Ag, Cu, Pb, Zn, Co, Ni, Sn and Cr), 'E-tech' elements used in clean energy and other environmental applications (e.g. neodymium and other rare earth elements) and energy (through enhanced methane generation) be recovered by leaching and other treatments whilst the material lies in situ, thus avoiding the need to actively mine the material and thereby minimising ecological and environmental impacts? The fundamental geoscience research question that underpins this is: How can we understand and manipulate the in situ biogeochemistry of the waste within the geological repository to recover resource? The rationale behind the research is to examine new technologies for resource recovery with a lower environmental impact than active ('dig and process') mining of wastes, or of virgin ores. The concept and technology of in situ leaching has been developed in the mining industry for recovery of uranium and copper, and is done by circulating solutions to extract the elements and/or stimulating and enhancing microbial leaching. The possibility of transferring this concept for application to recovery of resource from waste repositories has not been fully addressed previously. Wastes display diverse compositions, mineralogies and textures very different to that of ores and thus will require new science to understand and develop leaching methods to solubilise valuable components. We will consider resource extraction from the full range of wastes currently in UK waste repositories including industrial and commercial waste (anticipated to be metal-rich), incinerator and fuel ash, mineral wastes and municipal wastes to examine the idea of in situ leaching. We are particularly keen to identify during the grant which types of landfilled waste streams might be relatively enriched in certain resources and focus the research on recovery from these wastes as a starting point. We envisage that in situ leaching could sidestep many of the problems that prevent realisation of the resource potential of waste repositories, with important impacts not only in the UK but internationally. Furthermore, our aim is to not only investigate means to recover resource through in situ leaching but to also investigate how we can appropriately benchmark such processes (which we anticipate may have substantially lower environmental and human health impacts) in terms of life-cycle, human health and ecosystems service costs as well as public opinion for comparison to retrieval of landfilled resources by 'conventional' dig-and-process landfill mining and against conventional mining of the same resources. This aims to provide evidence to demonstrate not only that the techniques are technically feasible but that they offer reduced impact compared to conventional technologies, are acceptable to stakeholders and thus are a feasible and appropriate approach to future management of wastes.