The EU funded project CRM-geothermal aims to establish an overview of the potential for critical raw materials (CRM) in geothermal fluids across the EU and third countries (Ref). Within this framework, the geothermal sites of Tuzla, Seferihisar and Dikili in eastern Turkey have been visited in March 2023. To estimate the potential of CRM at these sites, a comprehensive sampling program was performed. Rock samples (drill gravel) of the production borehole and scaling from gas-water separators were obtained. Furthermore, sampling of geothermal fluids (gas and brine) and precipitates (salt) along the production line was performed.
Here, the results of the geochemical analyses of solid sample materials (drill gravel, scales and salt) are presented.
All analyses were performed in the ElMiE-Lab (Elements and Minerals of the Earth Laboratory) at German Research Centre for Geosciences Potsdam, Germany (https://labinfrastructure.geo-x.net/laboratories/8). For their major and minor element compositions, bulk samples of drill gravel and scales were analyzed with XRF and ICP-MS, respectively. Salt precipitates were analyzed for dry loss and mineral composition using XRD.@en

To enhance the EU's economic autonomy, feasible options for local sourcing of critical raw materials that would allow for shorter supply routes along with ethical and responsible value chains are under contemplation. Social acceptance of mining in Europe is, however, low, and the establishment of new mining sites faces strong public opposition. Therefore, innovative solutions for the production of primary raw materials need to be developed. A new idea for raw material extraction is the extraction of essential elements from geothermal fluids.

Deep geothermal fluids, increasingly used for energy production, often contain high concen-trations of dissolved ions and gases in commercially interesting concentrations. The EU-funded project CRM-geothermal aims to develop new technologies to extract these highly relevant elements, including helium, during geothermal production cycles. In this way, an environmentally friendly and socially acceptable exploration and exploitation method could be deployed.

One aim of the CRM-geothermal project is to gain an overview of the actual quantities of critical raw materials in various geothermal fluids in Europe by taking and analyzing fluid samples. In Turkey for instance, classical high enthalpy (volcanic) systems exist, which are representative for many geothermal areas worldwide. The sites are located at the edges of tectonic plates and close to areas undergoing volcanic activity. The brines are mixed with seawater and circulate in the deeper crust.

The data publication contains analyses results of three gas samples from Tuzla, two samples from Seferihisar geothermal power plant and one sample from the Dikili geothermal field in Turkey, taken in 2023 as part of the CRM-geothermal project.@en