Processes governing semi-metal - PGE linkage in crustal magmatic systems: opportunities for discovery and recovery

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A low carbon future for the UK depends on new and evolving technologies such as solar power and hydrogen fuel cells; these in turn are reliant on rare raw materials previously only mined in small quantities such as tellurium (Te), selenium (Se) and platinum group elements (PGE) - so called "E-tech" elements. However, at present there is considerable risk of supply shortages as the PGE can currently only be mined economically in a few countries; Te and Se are by-products of other commodities and supply risk is compounded by the historical lack of demand and an informal market ill-prepared for the predicted demand surge. Our research will tackle the security of supply of these E-tech elements by improving: i) our understanding of the processes that govern how and where these elements are concentrated in the Earth's crust; and ii) our ability to recover them with minimal environmental impact and economic cost.To do this we are taking advantage of their behaviour in the crust - the PGE are sulphur-loving, so readily concentrate in sulphide melts in magma bodies and form minerals with sulphur, whereas Se and Te also concentrate in sulphide melts, but become sulphur-replacers in minerals. Thus their behaviour and occurrence in natural systems are strongly controlled by the same processes; in fact Te and Se may be as important as sulphur in determining PGE behaviour, which leads to differences in the actual mineralogy of the ores. This then affects how they can be best processed in order to minimise energy usage and environmental impact.We propose to bring together researchers and industrial partners from academia, mining, mineral exploration, processing, solar panel production and fuel cell design, with the driving principle that better understanding the linkage between semi-metals and PGE in magmas will:a) provide new insight into the key processes that determine the cycling and concentration of Te, Se and PGEs in and through crustal systems;b) better quantify crustal fluxes and processes affecting sulphur (fractionation, contamination, melt immiscibility and volatile loss) and the related sulphur-loving elements;c) enable the development of existing and novel ore processing techniques to improve recovery of combined semi-metal and PGE, whilst mitigating the environmental footprint of extraction and processing.