Thermodynamics and Phase Diagram of the Salt Lake Brine System at 25°C I. Li+, K+, Mg2+/Cl−, SiO42−, -H2O System

Abstract Most salt lakes on Qinghai-Xizang Plateau belong to “Salt Lake Brine System” Li + ,Na + ,K + ,Mg 2+ /Cl − ,SO 4 2− ,borate—H 2 O. The system has high concentrations of lithium and boron and is different from the classical sea-water system. The investigation of the system is of theoretical and practical importance. The Pitzer ion interaction model for aqueous electrolytes has been used to describe the thermodynamics and phase equilibria of the salt brine system. Experimental studies of phase diagrams and thermodynamics for its many subsystems (ternary, quaternary and quinary) were performed. All the necessary parameters for the modeling the system were fitted by using a least-square analysis program thermodynamic and solubility data determined by us and those in literature. Finally, a prediction of solubilities for various systems was made. Calculated and experimental phase equilibrium for the system Li + , K + , Mg 2+ /Cl − ,SO 4 2− — H 2 O are presented for comparison in this paper.