关键词: 水盐体系, 溶解度, 相平衡, Pitzer模型

Abstract: Zabuye Saline Lake, Tibet, China, is unrivalled in the world for its very high salinity, in particular, for the very high concentration of ions of lithium, potassium, and boron in the brine. It belongs to alkaline and carbonate borate type salt lake. As a part of the study on phase equilibrium of the 6-component subsystem Li⁺, Na⁺, K⁺/Cl^-, CO₃^2-, B₄O₇^2--H₂O of the brine system, a study on the reciprocal quaternary system Li⁺, K⁺/Cl^-, CO₃^2--H₂O at 298 Kwas done with isothermal dissolution equilibrium method in the present work. The phase equilibrium of the reciprocal quaternary system Li⁺, K⁺/Cl^-, CO₃^2--H₂O at 298 Kwas studied with isothermal dissolution method in this work. The physico-chemistry properties of the corresponding equilibrium solutions such as densities, viscosities, refractive index, conductivities and pHvalue were determined. The dried salt diagram of the system consists of four crystallization fields (KCl, Li₂CO₃, LiCl·H₂O, K₂CO₃·3/2H₂O) and five isothermal solubility curves. There are no double slat or solid solution found. Pitzer's model of the electrolyte solution theory was used for parameterization from the results of solubility determination for subsystems and the prediction of solubilities for the reciprocal quaternary system was made. The solubility data of the experiment are in agreement with those calculated.

Key words: Aqueous solution system of salt, Solubility, Phase equilibrium, Pitzer's model