Arsenic speciation and toxicity in upcoming European lithium (Li) mines unveiled by (µ)-XAS

As lithium (Li) plays a critical role in Li-ion batteries powering electric mobility, Europe's dependence on external Li sources prompts initiatives to establish domestic production. Two mines in Portugal and Finland aim to commence exploitation of Li-rich pegmatites by 2025, enhancing Europe's Li supply security. However, environmental risks linked to Li extraction from hard rock resources remain unexplored, despite noted high arsenic (As) concentrations in tailings from pilot studies at these mines. Given the intricate mineralogy of As in these lithologies and its significant impact on mobility, spatially-resolved and bulk X-ray absorption spectroscopy (XAS) at the As K-edge will be used to quantitatively determine the As speciation in these tailings. Furthermore, we will investigate the mineralogical origin of As mobility by comparing our leaching test results to the solid As speciation in leaching residues at different stages of Li recovery in relation to waste management options.