KCl-PEG4000-H_2O三元体系288、298、308 K相平衡测定及计算  

Measurements and simulation for ternary system KCl-PEG4000-H_2O at 288, 298 and 308 K

作　　者：于旭东[1,2,3] 黄琴 王林 李茂兰[1] 郑洪 曾英 YU Xudong;HUANG Qin;WANG Lin;LI Maolan;ZHENG Hong;ZENG Ying(College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059, Sichuan, China;Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China;Center of Panxi Strategic Mineral Resources Multi-Purpose Utilization, Chengdu 610059, Sichuan, China)

机构地区：[1]成都理工大学材料与化学化工学院,四川成都610059 [2]中国地质科学院矿产资源研究所,北京100037 [3]四川省攀西战略矿产资源综合利用协同创新中心,四川成都610059

出　　处：《化工学报》2019年第3期830-839,共10页CIESC Journal

基　　金：国家自然科学基金项目(U1507111)

摘　　要：采用等温溶解平衡法研究了288、298、308 K下三元体系KCl-PEG4000-H_2O的相平衡关系,绘制了相应的相图、密度-组成图和折射率-组成图。研究发现:288、298、308 K下,三元体系KCl-PEG4000-H_2O无分层现象,只存在固液相平衡关系,其平衡相图由不饱和液相区(L)、一固一液区(S+L)和两固一液区(2S+L)构成,且两固一液区随温度升高减小。KCl溶解度随着溶液中PEG4000含量不断增加而减小。溶液中PEG4000含量小于0.50时,盐析率受温度影响较小;含量大于0.50时,盐析率随着温度升高呈减小趋势。采用修正后的Pitzer方程进行了三元体系KCl-PEG4000-H_2O (288、298、308 K)溶解度计算,对比发现,理论计算值与实验值吻合较好。The phase equilibrium relationship of the ternary system KCl-PEG4000-H 2 O at 288, 298 and 308 K was studied by isothermal dissolution equilibrium method. The corresponding phase diagram, density-composition diagram and refractive index-composition diagram were drawn. The results show that over the entire PEG 4000 composition rang studied only one liquid phase is obtained, without the biphase region formed at 288, 298 and 308 K. The phase diagram of system KCl-PEG4000-H 2 O consists of one homogeneous area with unsaturated liquid (L), an equilibrium area containing the solid phase of KCl and saturated liquid phase (S + L), one area with one liquid phase and two solid phases(2S+L). The area of (2S+L) decrease with the increasing of temperature, while the areas of (L) and (S + L) increase with the increasing of temperature. The solubility of KCl decreases with the addition of PEG 4000 at 288, 298 and 308 K. When w PEG4000 in the solution is less than 0.50, the temperature has little effect on the salting-out ratio of the system, while when w PEG4000 is higher than 0.50, the salting-out ratio of the system decreases with the increasing of temperature. The thermodynamics calculation of equilibrium data of system KCl-PEG4000-H 2 O at 288, 298 and 308 K was carried out by using the modified Pitzer equation, it can be seen from the comparison of experimental and calculation diagrams that the predictive solubilities agree well with the experimental values.

关 键 词：相平衡 热力学性质 溶解性 混合溶剂 PITZER方程 

分 类 号：O642[理学—物理化学]