Lithium extraction from geothermal brines in the Upper Rhine Graben: A case study of potential and current state of the art

Abstract

Increasing demand for lithium is leading to a rising focus on alternative, non-conventional lithium sources. These include geothermal brines, among others. The geothermal brines of the Upper Rhine Graben are characterized by comparatively high lithium concentrations of up to 200 mg L−1. To exploit this untapped potential, various direct lithium extraction (DLE) techniques can be used including adsorption and ion exchange.Several laboratory experiments on lithium extraction using inorganic sorbents such as lithium‑manganese oxides (LMO), lithium‑titanium oxides (LTO) and lithium‑aluminum-layered double hydroxide chloride (LDH) have been conducted in the past. Based on the promising results, various research projects are currently working on the development and implementation of the first pilot plants on existing geothermal sites.Before lithium extraction from geothermal brines can be commercialized, not only the sustainability of the resource must be investigated, but also the DLE process must be adapted to the respective site conditions. Finally, improved sorbent performance will be the main driver for future cost reductions and enhanced economics in lithium extraction from geothermal brines.