【摘要】 根据我国青海一里坪和东台吉乃尔盐湖晶间卤水Li Na K Mg Cl SO4 H2 O体系的组成制备了两种合成卤水储备溶液 ,采用等压法和改进的实验装置在 2 5℃下 ,从稀释到溶液中溶质NaCl达到饱和的浓度范围 ,对合成卤水溶液进行了等压测定 ,确定了它们的水活度aH2 O,和渗透系数 φ ;比较了两种卤水的热力学性质及其变化的规律 ,揭示了其天然卤水浓度差异的物理化学成因 .用盐湖卤水体系离子作用模型对水活度、渗透系数的计算值与本文的实验数据比较 ,对于一里坪和东台合成卤水 ,渗透系数的标准偏差分别为 0 0 0 78和 0 0 14 5 ;用该模型计算了东台晶间卤水 ,及其在 2 5℃等温蒸发实验不同阶段的浓缩卤水中 ,离子强度从 9 76 6到 2 0 5 2mol·kg-1范围可能析出的盐类的饱和度 ,给出了其变化规律 ,并与文献的盐类沉积和析盐顺序相比较 ,获得了合理一致的结果 ,从而证实了我们在Pitzer离子相互作用模型基础上所发展的盐湖卤水体系模型对描述和预测复杂天然盐湖卤水体系的热力学性质和蒸发析盐规律的适用性 .更多还原

【Abstract】 The water activities and osmotic coefficients have been determined at 25 ℃, over the range of concentrations from diluted up to saturated with respect to the solute of NaCl for the synthetic salt lake brine Li Na K Mg Cl SO 4 H 2O systems by isopiestic method using an improved apparatus. The two synthetic brine stock solutions were prepared respectively in accordance with the ionic strength fractions of the main ion components of Yi Li Ping and Dong Tai. salt lake interstitial brines on Qinghai Tibet plateau of China. The thermodynamic properties were compared between the two brines, and a cause of formation of the differences in concentrations between the two brines has been indicated physicochemically. The calculated osmotic coefficients using the ion interaction model of the salt lake brine systems agree with the experimental data obtained in this work, with standard deviations of 0 0078 and 0 0145 for Yi Li Ping and Dong Tai. synthetic brines respectively. The saturation indices [ln( K′/K )] were calculated for the salt components which may crystallize out from the brines for Dong Tai. interstitial brine and its concentrated brines at different evaporation stages in the isothermal evaporation crystallization experiment at 25 ℃, over the range of ionic strengths from 9 766 to 20 52 mol·kg -1 . The calculated results show the change rules in saturation indices of the salts in the brines during the evaporating of the brine and agree reasonably with the field observation result and with the salt sequences of crystallizations from the brine in the evaporation experiment. These studies demonstrate well the applicability of the model of the salt lake brine systems extended from Pitzer ion interaction model for the predictions of the thermodynamic properties and the mineral sequences to the salt lake brine systems containing lithium with high ionic strengths.更多还原