Selective lithium extraction from geothermal brines by sorption
Karlsruhe Institute of Technology, Germany
Lithium is an important compound in several industrial applications and is mostly found in lithium ion batteries (LIBs), ceramics and glass. Lithium deposits are hosted in pegmatites, sedimentary rocks and brines (i.e., salt lakes, salars, oilfield brines, and geothermal brines) comprising 25 - 26 %, 8 % and 59 - 66% of the world’s Li resources, respectively. Geothermal brines in the Upper Rhine Graben, Germany, with Li concentrations of up to 200 mg/L and resources of 2.7 Mt Li2CO3 represent potentially economically mineable Li deposits. The scope of our project is to extract Li from these high saline (i.e., TDS ~100 - 200 g/L) geothermal brines by sorption using natural and synthetic zeolite and clay minerals. These high saline brines are slightly acidic in pH and characterized by high concentrations of major cations (e.g., Na+ up to 60 g/L, K+ up to 4 g/L, Ca2+ up to 11 g/L and Mg2+ up to 1.9 g/L) and anions (e.g., Cl- up to 120 g/L and SO42- up to 1.5 g/L). Synthetic zeolite 13X and natural clinoptilolite-mordenite-montmorillonite mixtures have been used for preliminary sorption experiments. We performed batch sorption experiments with synthetic Li-solutions and variable concentrations and temperatures between 25 – 60 °C. Furthermore, we studied the effect of competing ions (e.g., Na+) on Li-sorption. Thereby, we investigate the different materials for sorption capacity and kinetics, chemical stability, structural effects of Li incorporation and their applicability to geothermal brines.
Gravity forward modelling and inversion based on the updated, enhanced gravity field solution in Antarctica
1Geodetic Earth System Research, Technische Universität Dresden, Germany; 2Institute of Astronomical and Physical Geodesy, Technical University of Munich, Germany
Geoscientific studies in Antarctica are extremely challenging due to the remote location of the continent, its harsh environment and difficult logistics. Additionally, the continental crust is covered by an up to 5 km thick ice sheet, which makes surface based geoscientific studies extremely difficult. Gravity field measurements and gravity based subsurface models are therefore essential in studying the structure, properties and processes of the Antarctic subsurface.
In the last decades a large database of airborne, shipborne and ground based gravity data has been compiled. Recently, all existing and new gravity data were processed to infer an enhanced gravity field solution for Antarctica.
Subsequently, this new gravity field solution can be used for further geophysical studies. We use gravity disturbances to study subglacial topography, sediment thickness and Moho depths to improve respective existing models in Antarctica.
Studying these parameters on a continental scale, we apply 2D Parker-Oldenburg inversion in combination with results from other gravity based studies and further constraining data.
Additionally, we make use of the higher resolution of the new gravity grid (5 km) to study smaller regions in more detail, specifically the Weddell Sea area and Queen Mary Land. Here, we use gravity forward modelling constrained with ice penetrating radar and seismic data to infer geometric structure and densities of the subsurface.
In this contribution we present results of the Parker-Oldenburg Inversion and discuss the underlying parameters. Also, we show the resulting 3D forward models of the Weddell Sea area and Queen Mary Land.
Lithospheric-scale 3D model of Sicily domain based on gravity analysis
1Università di Catania, Dipartimento di Scienze Biologiche Geologiche e Ambientali, Catania, Italy; 2GFZ German Research Centre for Geosciences, Potsdam, Germany; 3Istituto Nazionale di Geofisica e Vulcanologia – Sezione di Catania, Osservatorio Etneo, Catania, Italy
Sicily is a part of the central-Western Mediterranean area and represents a geotectonic boundary between the African and European plates. It is the result of a complex geological process based on a polyphasic evolution of a compressional step beginning with the Oligocene-Miocene clockwise rotation of Corsica-Sardinia simultaneously with the extensional processes of the Tyrrhenian basin. Consequently, the area is constrained by the continuing partial advance of the Sicilian-Maghrebian chain southwards and the Tyrrhenian extensional area towards the internal foreland areas (Hyblean domain). The study focuses on the creation of a 3D lithospheric-scale model of a 300 km x 400 km extended area in the central Mediterranean domain (Lat38°, Lat35°), which is consistent with the available geological and geophysical data, as well as with the observed gravity field. The reconstructed (simplified) geological setting consists of a lithospheric mantle, a crystalline basement (continental and oceanic crust), carbonates, the European margin and the Neogene-quaternary cover including volcanic bodies. The work aims to investigate the geometry of lithosphere integrating tomographic models in order to assess the major density contrasts and the lithospheric thermo-mechanical state. The regional 3D model provides also the boundary conditions for local thermal models to investigate afterwards.
Pre-processing of gravity data for 3 D-modelling of the lithospheric underground in the Ligurian Sea
Christian-Albrechts-Universität zu Kiel, Germany
The Ligurian Sea in the western Mediterranean Sea is a back arc basin created through the Apennines Calabrian subduction zone between 30 and 15 Ma ago. The inner geological structure of this basin is not well known. To improve the knowledge about the density distribution of the crust and lithosphere, we performed a pre-processing of gravity data prior to 3D-modelling. This work is related to research in the MB-4D priority and AlpArray project.
The satellite gravity gradients from GOCE were directly interpreted and used for filtering of different wavelengths to calculate residual fields, Bouguer and Free-Air anomalies as well as invariants and Euler-Deconvolutions. Furthermore, seismic profiles from several ship-borne surveys as well as OBS measurements of the AlpArray project (LOBSTER, GEOMAR, Kiel) and bathymetry data contributed additional information.
The processed data show an unknown anomaly offshore Marseille and the possibility of several underground structures with different densities. The basin itself is characterized by a mass surplus and positive anomalies with a maximum between Corsica and north-west Italia, while the anomalies underneath Corsica and Sardinia are neutral to negative.
The derived information will be used in the 3D-modelling software IGMAS+ to execute an inversion for the area and create a model of the mass distribution beneath the Ligurian Sea and its margins.
Lithospheric contact of the Western Carpathians with the Bohemian Massif in the light of seismic and new AlpArray gravity data
1Earth Science Institute of the Slovak Academy of Sciences, Slovak Republic; 2Department of Engineering Geology, Hydrogeology and Applied Geophysics, Faculty of Natural Sciences, Comenius University in Bratislava, Slovak Republic; 3Department of Seismology, Institute of Geophysics of the Czech Academy of Sciences, Czech Republic; 4Department of Theoretical Geodesy, Faculty of Civil Engineering, Slovak University of Technology in Bratislava, Slovak Republic
The Bohemian Massif represents the largest exposure of rocks deformed during the Variscan orogeny. Western Carpathians form an arc-shaped mountain range related to the Alpine orogeny. In our study, the lithospheric structure of the key tectonic units in the area and their contact zone was analyzed by 2D gravity modelling along the NW-SE oriented CEL09 profile of the CELEBRATION 2000 seismic experiment. New gravity map compiled at the initiative of the AlpArray Gravity Research Group was used. This map is based on a uniform reprocessing of the national terrestrial gravimetric databases of ten countries of the wider Alpine region. The resultant 2D density model based on gravity data was constrainted by results of seismic reflection and refraction method. Applied densities were defined by transformation of the modelled P-wave velocities. A good correlation between the density and seismic models was shown. The resultant 2D density model consisting of five principal layers (sediments, upper crust, lower crust, lower lithosphere and asthenosphere) shows differences between the older, cooler and thicker Bohemian Massif (in average: ~32 km thick crust, and ~120 km thick lithosphere), and the younger, warmer and thinner Carpathian-Pannonian region (~28 km crust, ~95 km lithosphere). The detected contact is delimited by a change in the Moho and the LAB topography, and assumes an overthrusting of the Western Carpathians onto the Bohemian Massif by ~30 km resulting in a neo-transformation of the crust/mantle and related lithosphere after subduction.