Speaker
Description
Lithium is one of the critical elements for the realization of electric mobility and energy transition. However, with an import quote of 86% (2010 – 2014), a contribution to global Li-production of less than 1% (2017) and negligible recycling, Europe depends almost entirely on Li-import. To reduce the dependency, Li deposits and new and unconventional resources are explored in the EU. One possible resource are brines from geothermal reservoirs of the Upper Rhine Valley in southern Germany. These brines are characterized by Li concentrations of up to 200 mg/L and total dissolved solid of ~120 g/L. Extraction of Li by evaporation is not feasible in the Upper Rhine Valley because of unsuitable climate, the necessity for huge evaporation ponds or the large energy consumption. One economically viable way to extract Li is the application of synthesized Li-Mn oxide sorbents. This sorbent is highly selective for Li due to its ion-sieve properties and is, therefore, suitable for saline brines with extremely complex composition.
The adsorption capacity, kinetics and the influence of competing ions on Li sorption was investigated for the synthesized Li-Mn oxide sorbent in batch experiments with synthetic Li+ solutions and natural geothermal brines. The mineralogy and geochemistry of the sorbents and batch solutions was characterized using ICP-OES, XRD, Raman and NMR spectroscopy.
The experiments reveal fast sorption kinetics with a desorption of >70% of the adsorbed Li within several minutes. The maximum Li sorption capacity is smaller for natural geothermal brines compared to pure Li+ solutions due to competing ions in the brine. While alkaline elements show a relatively little influence on Li sorption, other elements like Mn and Ba acted as major competing or sorption influencing ions.
We prove successfully that Li-extraction from geothermal brines in the Upper Rhine Graben with our specially synthesized sorbents is technologically feasible.
| Speaker Country | Germany |
|---|