273.15 K下Li2B4O7-LiCl-H2O体系热力学性质的等压研究及离子作用模型

用等压法研究了273.15 K下Li₂B₄O₇-LiCl-H₂O体系不同质量摩尔浓度分数的等压平衡浓度和水活度; 计算了LiCl和Li₂B₄O₇混合盐溶液的渗透系数等热力学性质. 用273.15 K下的实验数据对Pitzer离子相互作用模型进行了参数化研究, 拟合求取了273.15 K下Pitzer离子相互作用参数, 用获得的参数计算了LiCl和Li₂B₄O₇在Li₂B₄O₇-LiCl-H₂O体系中的活度系数. 273.15 K下由相应的Pitzer模型计算的渗透系数值与实验结果一致. 这对完善含锂、硼盐湖卤水体系的热力学模型具有重要意义.

Isopiestic Studies on Thermodynamic Properties and Representation with Ion-interaction Model for the Li2B4O7-LiCl-H2O System at 273.15 K

The isopiestic molalities and the water activities have been determined at 273.15 K for the Li2B4O7-LiCl-H2O system by isopiestic method,and the vapor pressures and the osmotic coefficient have been calculated from the measurements. The experimental data have been represented by the different forms of the ion interaction model based on the primary Pitzer model of osmotic coefficient. The Pitzer ion interac-tion parameters were evaluated from recent measurements by using multiple regression and iterative meth-ods. The activity coefficients of LiCl and Li2B4O7 for the system Li2B4O7-LiCl-H2O were calculated by the ion interaction model parameterized at low concentrations. The experimental data of osmotic coefficients measured and calculated by using the Pitzer model are in reasonable agreements. These studies are useful for improving the thermodynamic model for salt lake brine complex systems containing lithium and borate.