含锂碳酸盐六元水盐体系298K热力学性质和相平衡预测研究

Lithium salt lakes of carbonate type are well developed in Qinghai-Tibet Plateau, China. With its good reserves of Lithium, borax and potash, this kind of salt lakes are of great economic value. Lots of studies have been done on phase equilibrium, thermodynamic and physicochemical properties of the solution for lithium salt lake brines. However, few have been done on these of carbonate type brine. Furthermore, thermodynamic parameters for carbonate type are absence. Those have restricted the research and development process for the lithium salt lakes of carbonate type. The project aims at lithium salt lakes of carbonate type in Qinghai-Tibet Plateau of their Li, Na, K/ Cl, CO3, SO4-H2O six-component system. Using a suitable lithium ion-selective electrode, the mean activity coefficients of Li2CO3 in the ternary subsystems which contain Li and CO3 ions will be measured at 298.15K. Then the single electrolyte parameter of Li2CO3 and its mixing parameters will be obtained with a model. After that, a Pitzer model will be developed to predict mineral solubilities in the Li, Na, K/ Cl, CO3, SO4-H2O six-component system and in its five-component, quaternary and ternary subsystems at 298.15K. The data of phase equilibrium and physicochemical properties will be obtained. Use the research results, the concentration behavior of elements and the crystallization paths of salts of the brine from salt lakes of Zabuye, Dangxiang Cuo,Jiezechaka and Bangor will be predicted at 298.15K using the Pitzer model. After the research of this project, it will provide basic data for the lithium-bearing carbonate salt lake research and development in Qinghai-Tibet Plateau. This research also will be helpful to the advance of Pitzer ion-interaction model.

锂对国民经济和国防安全具有重要的意义，近年来，锂离子电池发展更是十分迅猛。我国青藏高原分布有多个碳酸盐型锂盐湖，该类型盐湖具有镁锂比低，易于开发的优势。但是对碳酸盐型锂盐湖卤水体系的研究还很不系统，尤其是缺少基础热力学数据，增加了研究开发的难度。本项目以298K下Li, Na, K/ Cl, CO3, SO4-H2O六元水盐体系为研究对象，采用电动势法和Pitzer电解质溶液模型，研究含锂碳酸盐型卤水体系的热力学性质和相平衡关系，获得该体系缺少的Pitzer模型参数，计算体系中各组分的溶度积常数、标准生成自由能、体系渗透系数等重要的热力学数据和溶解度数据。并进行碳酸盐型锂盐湖卤水的298K等温蒸发实验，运用Pitzer模型模拟碳酸盐型富锂卤水等温蒸发过程，进行对比研究。项目的研究成果将为碳酸盐型卤水提锂生产工艺提供科学数据，对高效利用青藏高原盐湖中锂资源，优化工艺路线具有重要意义。

锂对国民经济和国防安全具有重要的意义，我国青藏高原分布有多个碳酸盐型锂盐湖，该类型盐湖具有镁锂比低，易于开发的优势。本项目旨在组建用电动势法测定电解质溶液中Li2CO3的平均活度系数的实验装置，测定含Li, CO3三元体系的活度系数等热力学数据，计算Li2CO3模型参数，开展Li, Na, K / Cl, CO3, SO4-H2O六元水盐体系及其子体系298.15K相平衡和溶液物化性质研究，获得相平衡计算数据，并且进行碳酸盐型富锂卤水等温蒸发实验，并与模拟计算进行对比研究，为碳酸盐型卤水提锂生产工艺提供基础数据。.通过本项目研究，建立了电动势法测量电解质溶液电位的实验装置，形成了相关的实验测量、模型建立和数据处理方法。利用电动势法实验装置测定了多个　三元体系电解质混合溶液中的电位，根据电动势法测得的相关电解质的平均活度系数，建立了Pitzer模型，通过拟合运算，获得了Li2CO3的Pitzer模型参数和相关混合参数，利用获得的模型参数，建立了相平衡预测计算模型，通过模拟计算，获得了本项目研究体系中的三、四、五元子体系的相平衡数据，并绘制了相关相图。利用从野外采集的结则茶卡盐湖卤水，在25℃进行了卤水等温蒸发实验，考查了卤水中主要元素浓缩富集和盐类矿物析出规律。并针对结则茶卡、当雄错、班戈湖、扎布耶四个西藏碳酸盐型盐湖，进行了其卤水蒸发析盐规律的对比研究。项目的研究成果将为碳酸盐型卤水提锂生产工艺提供科学数据，对高效利用青藏高原盐湖中锂资源，优化工艺路线具有借鉴意义。.依托本项目，在SCI检索期刊发表论文3篇，在EI检索期刊发表论文1篇，在中文核心期刊发表论文6篇，共计10篇。积极进行学术交流，参加了两次国际学术会议和多次国内学术会议，并做了展板报告或口头报告。培养硕士研究生2名。