Biogeochemistry, Bioextraction and Biorecovery of Rare Earth Elements.

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The rare earth elements (REEs) are a group of 17 metals (La-Lu, Y, Sc) that have been discovered to have a number of useful chemical and physical properties and have been harnessed by a range of industries. REEs have critical uses in production of electronic components used in every-day items (computers, smartphones etc), ceramics, alloys, magnets, LCD screens and even in contrast agents used in medical imaging, such as during MRI scans. Whilst REEs are found in ores all over the world, current methods for extraction and separation of REEs from ores only work efficiently with ores containing large amounts of REEs relative to the amount of rock present ("high-grade ores"), whereas the majority of REE ore deposits worldwide contain low amounts of REEs and high amounts of rock ("low-grade ores"). Without effective extraction methods for low-grade ores, the global REE supply chain is dependent upon the few countries that have high-grade ore deposits, such as China. This means that the UK and EU are importing enormous amounts of these metals from China each year, at great cost (REE prices increase daily) and with not just associated shipping costs but an environmental impact of that transit and a high "carbon footprint".BioORE is a multi-disciplinary project lead by the University of Plymouth alongside the Universities of Manchester and Birmingham and the British Geological Survey, with the ultimate goal of exploring methods for extraction of REEs from low-grade ores found in the UK and EU, in order to try and provide us with a secure supply of these vital metals.The University of Plymouth has developed a bioextraction procedure in which low-grade REE ores can be broken down by 'rock eating' bacteria in carefully controlled reactors, leaving behind a small amount of rock waste (that could be recycled) and a solution containing a mixture of REEs. This procedure is relatively inexpensive and does not use any harmful chemicals or product any pollutants -event the CO2 produced by the bacteria during the process is trapped for recycling and not released into the environment. A further biorecovery process has been co-developed by the Universities of Plymouth and Birmingham in which REEs can be recovered back out of the mixture produced in bioextraction in a selective manner - that is to say that the process separates out the metals from the solution. This is achieved using controlled reactors containing bacteria embedded in a type of plastic, over which the REE solution flows. The bacteria produce large amounts of phosphate during their metabolism, which reacts with REEs producing REE phosphate biominerals, which form crystals all over the cells in the plastic matrix. By using a range of different bacteria and different conditions, we can selectively biorecovery REEs from mixtures. The biominerals can either be used directly by industries that need them or can be further processed either chemically or biologically to meet industry's needs.BioORE will bring together a range of international industries and will work with them to develop, optimise and scale-up these two biotechnologies with the goal of developing an effective method for REE extraction from low-grade ores. Use of a biotechnology is not only a means to fast and selective REE separation; it is also a 'green' technology, producing none of the harmful pollutants associated with current REE separation methods. These technologies will enable clean, 'green' REE production from low-grade ores found worldwide, permitting local production in countries that use them and reducing the CO2-burden associated to global transport.