富锂锶溴油田卤水六元体系288.15K介稳相平衡及化学模型研究

The metastable phase equilibria and the phase diagrams are the theoretical foundation for the exploitation of the brine resources. The mother liquor of the oilfield brine from the Nanyishan district in the Qaidam Basin contains high concentrations of lithium, strontium and bromine after the separation of potassium and boron. In this project, the climate in Nanyishan district will be simulated and the metastable phase equilibria of the six-component system Li+,Na+,Ca2+,Sr2+//Cl-,Br-–H2O and its quinary subsystem at 288.15K will be studied using the isothermal evaporation method. The solubilities and the corresponding physicochemical properties of the solutions in the above systems were determined. The dry-salt phase diagrams, the water phase diagrams, and the physicochemical properties versus composition will be plotted to evaluate the crystalization behaviors of the complex system. Pitzer’s electrolyte solution theroy and its extended Harvie-Weare equations (HW model) will be applied to calculate the solubilities of the above systems containing solid solution at 288.15 K. Combining the solubility data and the heats of dilution and mixing using the microcalorimetry method, the Pitzer single-salt parameters and mixing ion-interaction parameters of the six-component system at 288.15K will be fitted. Using the pitzer parameters and metastable solubilities, the theorized metastable equilibrium criterion will be obtained. Then, the Pitzer chemical model used to predict the solubilities of the six-component system at 288.15K will be constructed. The results of this project will help to demonstrate the chemical behaviors of the metastable phase for the mother liquor of oilfield brine and ascertain the enrichment regulation for lithium, strontium, and bromine of the brine in Nanyishan district. This study will enrich and develop the electrolyte solution theory and will be valuable in providing the theoretic foundation and scientific guidance in the comprehensive exploitation of lithium, strontium, and bromine from the mother liquor of the oilfield brines in Nayishan district.

卤水体系的介稳相平衡与相图是卤水资源开发利用的重要理论基础。本项目针对南翼山提钾硼后的油田老卤富含锂、锶、溴等特点，模拟当地夏季气候条件，拟采用等温蒸发法开展具有老卤组成特征的六元体系Li+,Na+,Ca2+,Sr2+//Cl-,Br-–H2O及其五元子体系288.15K介稳相平衡实验研究，测定上述体系的溶解度及物化性质并绘制相应相图；将Pitzer电解质溶液理论和Harvie-Weare公式应用于含固溶体的该六元体系，有机结合稳定平衡溶解度和量热法测定的稀释热、混合热实验结果，获取必需的单盐与混合离子作用参数，采用介稳平衡判据，构建该六元体系288.15K介稳溶解度理论预测模型，理论预测计算介稳溶解度。本项目研究结果将有助于揭示南翼山提钾硼后油田老卤的介稳相化学行为、探明卤水中锂锶溴的蒸发富集规律，丰富和发展电解质溶液理论，并为制定油田老卤综合利用方案提供重要的热力学基础数据。

本项目针对南翼山提钾硼后的油田老卤富含锂、锶、溴等特点，开展了具有老卤组成的卤水体系的介稳相平衡实验及化学模型研究，揭示了油田老卤的介稳相化学行为、探明了卤水中锂锶溴的蒸发富集规律，为油田老卤综合利用提供了重要的热力学基础数据。获得的研究成果如下：（1）模拟夏季气候条件，控制温度、风速和湿度，采用等温蒸发法完成了六元体系Li+,Na+,Ca2+,Sr2+//Cl-,Br-–H2O及其五元子体系288.15 K介稳相平衡实验研究，获得了锂锶溴水盐体系的介稳溶解度数据和液相物化性质，确定了相应体系的介稳相图和物化性质组成图；（2）完成了多个三元体系288.15 K稳定相平衡和热力学性质研究，补充了含锂钙锶溴卤水体系的稳定溶解度数据和热力学数据；（3）将Pitzer电解质溶液理论和HW公式应用于含固溶体的该六元体系，有机结合稳定相平衡法和等压法拟合了必需的Pitzer模型参数，采用介稳固液平衡判据，构建了该六元体系288.15 K介稳溶解度理论计算的Pitzer化学模型，并理论计算了上述体系介稳溶解度。已发表期刊论文13篇（含接收2篇），其中SCI论文9篇，会议论文7篇，培养在读研究生2名。