Inhaltsbereich
The effect of liquid-vapour immiscibility on fractionation processes (elements and isotopes) in hydrothermal systems
We investigate fractionation processes in liquid-vapour systems by experimental determination of element and isotope partitioning between coexisting brine and vapour in water-salts and water – salts – carbon dioxide systems. Conditions range from low-temperature -low pressure relevant to CO2-sequestration up to hydrothermal of 500°C and 500 bar. Experiments are performed in a large volume Ti-autoclave with extraction capabilities for immiscible fluids. Recent work addresses fractionation of copper and its isotopes between aqueous vapour and liquid in the systems CuCl-NaCl-H2O and CuCl-NaHS-NaCl-H2O, as well as trace element partitioning (Fe, Cu, Zn) between brine and carbon dioxide including applications to the geological storage of CO2.
© GFZ Potsdam- NaCl and B bromine concentrations in coexisting liquid-vapour pairs along the 380, 400,
430, and 450 °C isotherms. From: Liebscher A., Lüders V., Heinrich W., Schettler G. (2006): Br/Cl signature of hydrothermal fluids: liquid–vapour fractionation of bromine revisited. Geofluids, 6, 2, 113-121.
© GFZ Potsdam- Experimentally determined KD(Br-Cl) liquid-vapour values at 380, 400, 430, and 450 °C as function of the distance to the critical curve in the H2O-NaCl system (Bischoff and Pitzer, 1989). The data indicate preferential partition of Br into the liquid compared to Cl at all run conditions. Results of Berndt and Seyfried (1990, stars) notable deviate from the results of this study and indicate the opposite fractionation behaviour of Br and Cl.
Contact: Wilhelm Heinrich