Ion pairing of (hydrogen)tungstate anions with sodium in hydrothermal fluids and its impact on W transport in the Earth's crust

This project aims at improving our knowledge about the tungsten speciation in hydrothermal fluids responsible for ore deposit formation. These new data will be obtained using in-situ XAS to study the pairing of the (hydrogen)tungstate ion with alkalis (Na, K). The analysis will be coupled with thermodynamic models, to determine their stability and solubility in aqueous fluids under a wide range of temperatures, pressures and pH. The results obtained in this proposal are indispensable for the rigorous interpretation and valorization of previous in-situ XAS measurements as well as literature data.