Evaporite Geochemistry - Modelling - Raw Materials - Recycling

Our expertise and research in the field of salt and mineral chemistry is focussed on the hexary system of oceanic salts (Na-K-Mg-Ca-Cl-SO₄-H₂O) including acids, bases and CO₂/carbonate as well as the modelling (THEREDA) for the evaluation / prediction / use / application of dissolution and crystallisation processes. By expanding the system to include, for example, lithium or subgroup elements such as nickel and cobalt, we develop processes and process understanding for raw material extraction and recycling processes.

Contact person

Selected publications

• Crystallisation of metastable monoclinic carnallite, KCl-MgCl₂-6H₂O: missing structural link in the carnallite family.
  M. Pannach, I. Paschke, H. Schmidt, D. Freyer, W. Voigt.
  Acta Crystallographica Section C: Structural Chemistry 76(5), 507-512 (2020) read online
• Higher hydrates of lithium chloride, lithium bromide and lithium iodide.
  J. Sohr, H. Schmidt, W. Voigt.
  Acta Crystallographica Section C: Structural Chemistry 74(2), 194-202 (2018) read online
• Oceanic salts - which do we know? [Oceanic salts - which do we know?].
  W. Voigt.
  Journal of Salt History 13/14, 191-208 (2017)
• What we know and still not know about oceanic salts.
  W. Voigt.
  Pure and Applied Chemistry 87, 1099-1126 (2015) read online
• Chemistry of salts in aqueous solutions: Applications, experiments, and theory.
  W. Voigt.
  Pure and Applied Chemistry 83, 1015-1030 (2011) read online
• Polyhalite and its analogous triple salts.
  G. Wollmann, D. Freyer and W. Voigt.
  Monatshefte für Chemie - Chemical Monthly 139, 739-745 (2008) read online
• Solubility of inorganic salts and their industrial importance.
  In Developments and applications in solubility - Theory, techniques and results,
  T.M. Letcher, 390-406. W. Voigt (RSC-Royal Society of Chemistry, London, 2007) read online
• The measurement of sulphate mineral solubilities in the Na-K-Ca-Cl-SO₄-H₂O system at temperatures of 100, 150 and 200°C.
  D. Freyer and W. Voigt.
  Geochimica et Cosmochimica Acta 68, 307-318 (2004) read online

FuE final reports

• Fine exploration of the rocksalz contour in the area of future closure structures in HAW repositories by in situ Raman spectroscopy - SaRa. Final report on the BMUV project - in progress.
  
• Feasibility study on the applicability of low-temperature Sal melting for V closure measures of E repositories for radioactive waste in the host rock salt - SalVE. Final report on the BMUV project (2024).

Scientific presentations, national - international

-Selection-

• J. Sohr: In situ Raman spectroscopy of rock salt contours in planned drift sealing locations of HAW repositories (SaRa project).
  14^th US/GERMAN WORKSHOP on Salt Repository Research, Design & Operation. Manchester (UK) 24/06/2024.
• D. Freyer: The host rock salt - an overview on the oceanic salt system Na-K-Mg-Ca-Cl-SO₄-H₂O.
  ABC-SALT VII, Santa Fe, New Mexico, USA, 15-16 June 2023.
• M. Pannach, D. Freyer: Modelling of Solubility Equilibria of Sorel Phases up to 60 °C.
  ABC (Actinide Brine Chemistry)-Salt VI Workshop, Karlsruhe, 25-26 June 2019.
• W. Voigt:What we know and still not know about oceanic salts.
  ISSP 16, Karlsruhe, 21-25 July 2014.
• M. Oestreich, D. Freyer: Solubilities of Basic Magnesium Salt Hydrates at different temperatures.
  ISSP 15, Xining, China, 2012.
• D. Freyer: Phase equilibria in multicomponent salt systems at enhanced temperatures: new data and modelling for safety assessment of radioactive waste disposal.
  ISSP 2002, Bulgaria.