Hydrothermal large-cavity high-temperature-pressure device combined with Synchrotron radiation X-ray absorption spectroscopy

A hydrothermal large-cavity high-temperature and high-pressure device has been meticulously devised for synchrotron radiation X-ray absorption spectroscopy. The experimental temperature and pressure can reach 600 ℃ and 200 MPa with an independent control system. The hydrothermal reactor vessel is equipped with three beryllium windows and is ingeniously designed to accommodate diverse testing modalities within the experimental facility. This apparatus was implemented to investigate the complex species of Au （gold） in chlorine-containing fluids under high-temperature and high-pressure circumstances at the Shanghai Synchrotron Radiation Facility （SSRF）. The experimental outcomes disclose that， at relatively low temperatures and pressures， Au predominantly exists in the form of the [AuCl₄]^- complex. Nevertheless， within the temperature range of 200 - 500 ℃ and pressure range of 72.1 - 92.4 MPa， the complexation form transitions to [AuCl₂]^-. These discoveries are congruent with prior research， further substantiating the dependability of our experimental methodologies and equipment. Moreover， this device holds the potential to simulate the evolution， species， as well as the physical and chemical properties of metallogenic elements in geological fluids under simultaneous high-pressure and high-temperature conditions.