Modeling of brine-rock interactions in German geothermal systems for future lithium recovery

Presented is the framework of the modeling part of the project "Li-Fluids". For this purpose, electrolyte models are presented that can be used for a modeling of lithium-bearing minerals. The identification of sources of lithium and their integration into the hydrogeochemical calculation programme PHREEQC allow the simulation of lithium release from geothermal reservoirs in principle. However, there are also challenges: Brines can only be calculated validly with the Pitzer approach, which limits the number of minerals considered. There are other databases that are suitable for high ionic strengths, but more research is needed for appropriate Li-mineral modeling in the future.