DGGV-E-Publikationen

Title: Methods for the extraction of rarer metals and base chemicals from geothermal brines

Authors:
Hans-Jürgen Friedrich

Institutions:
Fraunhofer Society,Institut for Ceramic Technologies and Systems (IKTS), Germany

Event: GeoKarlsruhe 2021

Date: 2021

DOI: 10.48380/dggv-0b92-nk26

Summary:
Geothermal brines may contain a plenty of chemical elements in a wider range of concentrations ranging from trace to bulk concentration level. This makes such brines interesting for the winning of metals as well as of bulk chemicals. Main constraints are the high temperatures and pressures that should be maintained during processing, the accompanying gases like Methane and/or Hydrogen Sulfide and the enrichment of naturally occuring radionuclides during processing.

This can make such processes troublesome.

Coming from research in radioactive scales abatement a process and a galvanic high pressure cell were devoloped for electrochemical separation of valuable trace metals like Sb, Tl, Te from geothermal brine and testes over a longer period at our test facility at Neustadt-Glewe, Northern Germany. We also examined the extraction of numerous metals from brine sample from the Großschönebeck geothermal site by means of electrochemical and selective adsorption methods. In Addition based on brines from the Stassfurt geological series the winning of base chemical like hydrochloric acis and sodium hydroxide solutions was also shown to be possible by means of electromembrane processes. The economic potential of such methods will bei evaluated based on experimental data.