| Work Detail |
The ThermIon project from Fraunhofer ISE aims to take into account the entire process chain, from brine pretreatment to lithium extraction and crystallization of lithium carbonate or lithium hydroxide, through to controlled brine return. The new process is intended to be environmentally friendly and cost-effective. By Petra Hannen .
The Fraunhofer Institute for Solar Energy Systems in Germany is working with partners from science and industry to develop and demonstrate an environmentally friendly, economically attractive and innovative technology for extracting lithium from thermal water.
In theory, existing geothermal power plants in the Upper Rhine Plain and the North German Basin can cover between 2% and 12% of Germanys annual lithium demand reliably for several decades and at low environmental costs. However, there is still no ready-made technology for commercializing lithium extraction from thermal water.
This is where the three-year “ThermIon” project at Fraunhofer ISE comes in. The ambitious undertaking will take into account the entire process chain, from brine pretreatment to lithium extraction and crystallization of lithium carbonate or lithium hydroxide, right through to controlled brine return.
As announced by Fraunhofer ISE on Wednesday, the challenge is to selectively extract lithium from geothermal waters without disturbing their complex geochemical balance and without running the risk of precipitating other ingredients such as silicates and calcites. Such precipitation would entail considerable technical risks for the operation of a geothermal plant. The project will further develop the technology of direct lithium extraction (DLE), which very selectively extracts only lithium from the brine and leaves the other elements intact.
The particular challenge of DLE technologies is to operate them at high temperatures and very high pressures, up to 30 bar, for a prolonged period. The research team is using a lithium-ion pump process, where lithium ions are stored in a special lithium manganese oxide electrode and released into a recovery solution when the polarity is reversed. This allows for a concentrated solution of highly pure lithium chloride.
The team is optimistic that the process will also work on a larger scale and that in the future lithium can be extracted directly from the brine during the operation of a geothermal plant. Since the thermal water is easily comparable with that from other locations in the Upper Rhine Plain, the results can be transferred to the 13 planned geothermal projects, which can be developed as pure heat projects or as power and heat projects. |
