Dissolution thermodynamics of smithsonite in alkaline iminodiacetate aqueous solution

Abstract

The thermodynamic model of the dissolution of smithsonite (ZnCO3) in alkaline iminodiacetate aqueous solution (Ida2−–H2O system) was constructed according to the thermodynamic equilibrium equations in the system. Thermodynamic results of total concentration of Zn2+, free concentration of Zn2+, free concentration of Ida2−, free concentration of CO32−, species distribution of Zn2+ and species distribution of Ida2− changed with total concentration of Ida2−, and pH value were investigated respectively in the system at 298 K. The total concentration of Zn2+ increases with increasing total concentration of Ida2− at constant pH value. The optimal pH area for the dissolution of ZnCO3 in Ida2−–H2O system is pH 8–11. In this area, the total concentration of Zn2+ increases smoothly with increasing of pH, above 90% of Ida2− is used for the formation of Zn(Ida) 22−, and above 99% of Zn2+ is formed as Zn(Ida) 22−.