【作者】 吴鹏；

【导师】 周桓；

【作者基本信息】 天津科技大学 ， 海洋化学， 2020， 硕士

【摘要】 基于水盐体系相图,针对青海盐湖资源开发中,复杂卤水系统所呈现的复杂相平衡问题,在国家自然基金项目和联合基金的支持下,对盐湖涉及到相关体系进行了研究。本研究以电解质NRTL热力学模型为基础,确定模型到的液相特征参数以及固相热力学常数,从而构建水盐体系全温热力学模型。通过该综合热力学模型可以计算溶液物理化学性质,预测全温相图及拓扑结构等。本研究的体系为Li⁺,K⁺,Na⁺,Mg²⁺//SO₄^2--H₂O体系及相关子体系。（1）液相特征参数的确定。对于二元体系,需要确定四个二元体系的8个盐对-水交互作用参数。通过饱和蒸气压、比热、冰点等文献数据进行回归优化。对于四个三元体系Li₂SO₄+Na₂SO₄+H₂O、Li₂SO₄+K₂SO₄+H₂O、Li₂SO₄+Mg SO₄+H₂O、Na₂SO₄+K₂SO₄+H₂O涉及到的八个盐对-盐对交互作用参数,可以利用三元体系的全温溶解度实验数据回归优化得到。（2）固相热力学常数。通过二元体系溶解度数据回归优化得到15个固相热力学常数,通过三元体系溶解度数据回归优化5个复盐的热力学常数,总共获得20个固相热力学常数。（3）基于模型确定的参数进行了二元体系的物性计算和获得了全温溶解度曲线。得到了三元体系最低共溶点到高温范围的全部零变量点和共饱线,进而获得全温完整相图以及完整的相图拓扑结构,四元体系的实现了多温相图的计算。全温范围完整相图得到了可视化表达。结果表明,模型计算值和文献报道的数据其吻合性较好,说明本研究建立的热力学模型能够对于全温范围物性进行计算以及全温范围完整相图计算。（4）通过相图实验,获得了Li₂SO₄+Na₂SO₄+H₂O三元体系部分两盐共饱的零变量点的实验数据,并与模型计算值进行了验证比较。结果表明,该热力学模型具有良好的重现性和预测性。更多还原

【Abstract】 Based on the phase diagram of the water-salt system,aiming at the complex phase balance problem presented by the complex brine system in the development of salt lake resources in Qinghai,with the support of the National Natural Science Foundation project and the joint fund,the related system of salt lakes was studied.This study is based on the electrolyte NRTL thermodynamic model,and determines the liquid phase characteristic parameters and solid phase thermodynamic constants obtained by the model,so as to construct a full temperature thermodynamic model of the water-salt system.The comprehensive thermodynamic model can be used to calculate the physical and chemical properties of the solution,predict the phase diagram of total temperature,and the topological structure.The system of this study is Li⁺,K⁺,Na⁺,Mg²⁺//SO₄^2--H₂O system and related sub-ystems.（1）Determination of liquid phase characteristic parameters.For binary systems,eight salt-water interaction parameters for four binary systems need to be determined.Regression optimization was performed using literature data such as saturated vapor pressure,specific heat,and freezing point.For the four ternary systems Li₂SO₄+Na₂SO₄+H₂O,Li₂SO₄+K₂SO₄+H₂O,Li₂SO₄+Mg SO₄+H₂O,Na₂SO₄+K₂SO₄+H₂O,,the eight salt-pair interaction parameters involved,you can use the full ternary system Temperature solubility experimental data were obtained by regression optimization.（2）Solid phase thermodynamic constant.15 solid-phase thermodynamic constants were obtained by regression optimization of binary system solubility data,and 5 double salts thermodynamic constants were optimized by regression of ternary system solubility data.A total of 20 solid-phase thermodynamic constants were obtained.（3）Based on the parameters determined by the model,the physical properties of the binary system were calculated and the full temperature solubility curve was obtained.All the zero-variable points and co-saturation lines of the ternary system from the lowest eutectic point to the high temperature range were obtained,and then the complete temperature diagram and the complete phase diagram topology were obtained.The quaternary system realized the calculation of the multi-temperature phase diagram.The complete phase diagram over the full temperature range is visualized.The results show that the calculated values of the model are in good agreement with the data reported in the literature,indicating that the thermodynamic model established in this study can calculate the physical properties of the full temperature range and the complete phase diagram of the full temperature range.（4）Through phase diagram experiments,the experimental data of the zero-variable point where the two salts are saturated in the ternary system of Li₂SO₄+Na₂SO₄+H₂O are obtained and compared with the model calculations.The results show that the thermodynamic model has good reproducibility and predictability.更多还原