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.

锂（Li）是驱动电动出行的锂离子电池的关键原材料，欧洲对外源锂资源的依赖催生了本土锂产能建设的相关举措。葡萄牙与芬兰的两座矿山计划于2025年前启动富锂伟晶岩的开采工作，此举将提升欧洲的锂供应安全保障能力。然而，尽管上述矿山的试点研究已探明尾矿中存在高浓度砷（As），但硬岩提锂所关联的环境风险仍未得到充分研究。鉴于该类岩性中砷的矿物学特征极为复杂，且其环境迁移性影响显著，本研究将采用基于砷K边（As K-edge）的空间分辨与整体X射线吸收光谱（X-ray absorption spectroscopy, XAS）技术，定量测定这些尾矿中的砷化学形态。此外，本研究将对比不同锂回收阶段浸出残渣内的固态砷化学形态与浸出试验结果，并结合废弃物管理方案，探究砷迁移性的矿物学成因。