Geology to Metallurgy of Critical Rare Earths: sustainable development of Nd and HREE deposits

点击翻译按钮获取中文摘要

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.