ИСТИНА

The solubility of PdS(cr) (vysotskite) was measured in aqueous H2S (0.1–2.0m, mol/kg H2O) and H2S + NaOH (0.02–0.4m H2S + 0.05–0.4m NaOH) solutions at 4, 25, 75°C/1 bar and at 450, 490°C/1000 bar. The Gibbs free energy values of Pd(HS)2° and Pd(HS)3– are calculated and are the basis for the preliminary constants of PdS(cr) dissolution reactions with the formation of these complexes K° Pd(HS)2°; K°Pd(HS)3–. These constants in a temperature range of 4–490 °C are fi tted to the density model equation, which can be u sed to predict the solubility of Pd-bearing minerals up to 700 °C and 2000 bar.