摘要
The metastable solubilities and the physicochemical properties including density and pH of the reciprocal quaternary system（LiCl＋MgCl2＋Li2SO4＋MgSO4＋H2O） at 348.15 K and 0.1 MPa were determined using the isother- mal evaporation method. The dry-salt diagram and water-phase diagram were plotted based on the experimental data. There are five invariant points, eleven tmivariant curves, and seven crystallization zones corresponding to hexahy- drite, tetrahydrite, kieserite, bischofite, lithium sulfate monohydrate, lithium chloride monohydrate and lithium car- nallite. Comparison between the stable and metastable diagrams at 348.15 K indicates that the metastable phenome- non of magnesium sulfate is obvious, and the crystallization regions of hexahydrite and tetrahydrite disappear in the stable phase diagram. A comparison of the metastable dry-salt phase diagrams at 308.15, 323.15 and 348.15 K shows that with the increasing of temperatttre the epsomite crystallization zone disappears from the dry-salt phase diagranl of 303.15 K, and a new kieserite crystallization zone is presented at 348.15 K. The density and pH in the metastable equilibrium solution present regular change with the increasing of Janecke index J（2Li＋）, and the calculated densities using the empirical equation agree well with the experimental values.
The metastable solubilities and the physicochemical properties including density and pH of the reciprocal quaternary system（LiCl＋MgCl2＋Li2SO4＋MgSO4＋H2O） at 348.15 K and 0.1 MPa were determined using the isother- mal evaporation method. The dry-salt diagram and water-phase diagram were plotted based on the experimental data. There are five invariant points, eleven tmivariant curves, and seven crystallization zones corresponding to hexahy- drite, tetrahydrite, kieserite, bischofite, lithium sulfate monohydrate, lithium chloride monohydrate and lithium car- nallite. Comparison between the stable and metastable diagrams at 348.15 K indicates that the metastable phenome- non of magnesium sulfate is obvious, and the crystallization regions of hexahydrite and tetrahydrite disappear in the stable phase diagram. A comparison of the metastable dry-salt phase diagrams at 308.15, 323.15 and 348.15 K shows that with the increasing of temperatttre the epsomite crystallization zone disappears from the dry-salt phase diagranl of 303.15 K, and a new kieserite crystallization zone is presented at 348.15 K. The density and pH in the metastable equilibrium solution present regular change with the increasing of Janecke index J（2Li＋）, and the calculated densities using the empirical equation agree well with the experimental values.
基金
Supported by the National Natural Science Foundation of China（Nos.U1607129, U1607123, 21773170）, the China Postdoctoral Science Foundation（Nos.2016M592827, 2016M592828）, the Application Foundation and Advanced Technology Program of Tianjin, China（No. 15JCQNJC08300）, and the Yangtze Scholars and Innovative Research Team of the Chinese University（No.IRT-17R81 ）.
