Thermodynamic properties of platinum chloride complexes in aqueous solutions: Derivation of consistent parameters from literature data and experiments on Pt solubility at 400-475°C and 1 kbar.

The solubility of Pt in acidic chloride solutions was measured at 400-475°C and P = 0.8-1.0 kbar using an autoclave technique and the analysis of the dissolved component after quenching. The PtCl complex was identified as the main Pt species at experimental parameters, m(NaCl) = 0.1-3.0 mol/kg HO and m(HCl) ∼0.01. The thermodynamic parameters of the Helgeson-Kirkham-Flowers (HKF) model were determined for Pt and Pt-Cl complexes (PtCl n = 1-4) by analysis of literature data and their adjustment with obtained results. The solubility of Pt under supercritical P- T parameters calculated using these parameters is similar to Pd solubility. The thermodynamic properties and HKF model parameters for aqueous species determined in this study were incorporated into the on-line version of the FreeGC database (), which allows calculation of the Gibbs free energy of system components and equilibrium constants of reactions with these species. [ABSTRACT FROM AUTHOR]