柴达木盆地盐湖老卤体系动态相平衡研究

The mother liquor after potassium extracting in the Qaidam Basin is famous for its characters of high concentrations ration of lithium and magnesium, and the high concentrations of lithium, boron and magnesium ions in the world. The mother liquor brine belongs to the pseudo-five-component-system (Li+, Mg2+∥Cl-, SO42-, borate - H2O). It is essential to establish the dynamic phase equilibria of this mother liquor to promote the fine separation and comprehensive utilization of the mother liquor resource. On the basis of a large amounts of research works and datum accumulations on the phase equilibria and phase diagrams, research works on this project will be mainly focused on the three aspects to overcome the technical obstacles of the traditional phase equilibria and solution chemistry studies such as too long time to research equilibrium, and the original components and minerals are difficult to chose: Firstly, demonstrate the inner links of macroscopic thermodynamic properties of different aqueous lithium borates and the microstructure ion-interaction in the borate solutions through innovating the on-line insitu measurement method of the advanced micro-calorimetric technique to determine the heat capacities, mixing heats and the continuous low-temperature heat capacities for a series of the aqueous borate mother liquor systems containing lithium and magnesium ions; Secondly, extend the Pitzer electrolyte solution theory to obtain the whole model parameters and the temperature-correlation equations; Thirdly, and then, to establish the dynamic phase equilibria of the mother liquor brine systems in the Qaidam Basin.

柴达木盆地盐湖提钾后老卤属于高镁锂比、富锂、硼、镁的战略资源，老卤组成属于赝五元体系Li+, Mg2+∥Cl-, SO42-, borate - H2O，其动态相平衡对于盐湖老卤资源开发的系统性、配套化、精细化分离及其综合利用至关重要。本课题拟在已有的水盐体系相平衡与相图研究工作和大量资料积累基础上，克服传统相平衡和溶液化学研究的技术障碍，解决硼酸盐相平衡研究原始组份选择困难和达到平衡所需时间甚长的难题，借助先进的低温绝热微量热技术，精确测定盐湖老卤系列锂镁硼酸盐溶液体系热容、混合热和低温热容热力学性质，拟合获取迄今极为缺乏的老卤硼酸盐体系模型参数及其温度关联式，构建盐湖老卤体系动态相平衡化学模型，充分发挥溶液理论模型的预测作用，实现老卤体系稳定与介稳动态相平衡预测，为盐湖资源综合利用提供重要的化工基础数据，促进我国柴达木盆地盐湖资源综合开发利用。

柴达木盆地盐湖提钾后老卤相平衡与相图动态预测对于促进盐湖老卤资源有效开发利用、推动地方经济发展具有重要的意义。本项目针对盐湖老卤体系，合成了系列的碱金属和碱土金属硼酸盐，获得了相应的硼酸盐矿物的固体多温比热及其温度关联式；系统地揭示了盐湖碱金属和碱土金属硼酸盐水溶液体系多温条件下的体积性质，首次获得相应的表观摩尔体系、偏摩尔体系、热膨胀系数及其水溶液体系离子相互作用参数及其温度关联式；系统地完成了锂、镁硼酸盐水溶液体系多温条件下的渗透系数、活度系数的等压法研究和多温条件下的热容、溶解热、稀释热和混合热量热法研究，首次获得了老卤体系平衡固相单盐参数及其平衡固相矿物平衡判据及其温度关联式；结合多年的研究工作积累，拓展了盐湖硼酸盐卤水价系中至今未见报到的多温相平衡实验，构建了柴达木盆地盐湖含硼酸盐的老卤体系相平衡动态预测化学模型及其溶解度动态预测系统。在项目执行过程中，出版中文著作1部、英文合著1章，发表SCI论文26篇(其中JCR一、二区论文17篇），受理国家发明专利1项，获天津市自然科学二等奖和国际学术奖William D. Williams Award。主办国际会议1次、协办国际会议1次，参加国际会议1次、全国性学术会议3次。培养博士1名、硕士4名。超额完成了本项目任务。