Abstract:Thermodynamics of arsenite sulfidation in alkaline solutions were investigated to optimize solvent extraction process of thioarsenite under high-alkalinity condition. The concentration curves of AsIII ions are determined with changes of pH values and S/As molar ratio based on the known thermodynamic data. Furthermore, the effects of pH and sulfidizing agent dosage on sulfidation and products morphology are discussed respectively. The results show that though feasible in thermodynamics, sulfidation process is probably inhibited due to high alkalinity. Increase of sulfidizing agent dosage can effectively promote sulfidation process.