六元体系Li， Mg，K// Cl，SO4，B4O7—H2O低温0℃介稳和稳定液固相平衡研究

There are many magnesium sulfate subtype salt lakes in Qaidam Basin of Qinghai province, which are rich in lithium,boron, magnesium and potassium. In order to use such natural energies as the energy of the sun, the wind and low temperature condition to separate inorganic salt products from the salt lake brines with the method of natural freezing, the researth of stable and metastable phase equilibria and phase diagrams at low temperature is necessarily urgent. The study on stable and metastable phase equilibria for the winter magnesium sulfate subtype brines has not been reported systemically. The study about the experiments and its corresponding theories of stable and metastable phase equilibria at low temperature is one advanced research for the salt-water phase equilibrium system in the world.. The study on stable and metastable phase equilibria and phase diagrams at 0℃ for the system Li，Mg，K// Cl，SO4，B4O7-H2O are to aim at the sulfate magnesium subtype salt lake winter's brines system. The calculated model of solubilities for stable equilibria will be made with the application of Pitzer's equation. The phase diagrams of the six-component systems and corresponding to the ternary to quinary subsystems will be plotted, respectively. At last ,according to the study results of stable and metastable phase equilibria, the comprehensive utilization program of magnesium sulfate subtype winter's brines will be made. The mineralizing regularity of salt lake minerals are also explained during the process.

我国青海柴达木盆地有许多富含硼锂钾镁的硫酸镁亚型盐湖，利用当地自然条件太阳能、风能和低温进行卤水自然蒸发和冷冻结晶分离无机盐产品迫切需要该类型卤水体系介稳和稳定相平衡与相图的研究成果作指导；而针对硫酸盐型硫酸镁亚型盐湖卤水的低温介稳和稳定相平衡研究未见系统完整的研究报道，低温相平衡的实验及其相应的理论研究是世界水盐体系相平衡研究的前沿课题。本项目拟针对硫酸镁亚型盐湖卤水完成0℃六元体系Li， Mg，K// Cl，SO4，B4O7-—H2O介稳和稳定液固相平衡的研究，测定相应相平衡的溶解度数据，确定盐类矿物低温介稳和稳定相平衡条件下的结晶规律，并应用Pitzer电解质溶液理论计算0℃条件下的相平衡关系,绘制上述六元体系及其五元、四元子体系和三元子体系的介稳和稳定相图；根据固液相平衡的研究成果，制定盐湖卤水综合利用方案，阐明盐湖矿物的成矿规律。

根据项目的研究计划，针对我国青海柴达木盆地硫酸镁亚型盐湖富含硼锂钾镁的特点，本项目开展了硫酸镁亚型盐湖卤水0℃六元体系Li， Mg，K// Cl，SO4，B4O7-—H2O介稳和稳定液固相平衡的研究，测定了上述六元体系所包含的三元子体系，四元子体系和五元子体系在0℃时稳定相平衡和介稳相平衡的溶解度数据和密度，确定了盐类矿物低温0℃时介稳和稳定相平衡条件下的结晶析盐规律，补充开展了部分含钠锂钾硼体系相平衡研究，补充开展了部分含锂钾硼体系热力学性质的研究，并应用Pitzer方程对部分体系的稳定相平衡进行了模拟计算,绘制了上述六元体系中的五元子体系、四元子体系和三元子体系的介稳平衡和稳定平衡相图；根据上述固液相平衡的研究成果，制定硫酸镁亚型盐湖卤水综合利用方案，阐明盐湖矿物的成矿规律。依托本项目，发表了学术论文15篇（第一标注），其中会议论文1篇，SCI收录英文学术论文10篇，此外还发表了第二标注SCI收录学术论文20篇，参加了第十八届全国化学热力学和热分析学术会议，培养了6名硕士研究生和2名博士研究生，超额完成了项目的预期成果。