Solid and Liquid Metastable Phase Equilibria in the Aqueous Quaternary System Li＋, Mg2＋//SO42-, Borate-H2O at 273.15 K

• Published in: Chemical research in Chinese universities 2017-08, Vol.33 (4), p.655-659
• Main Authors: Meng, Lingzong, Guo, Yafei, Li, Dan, Deng, Tianlong
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Inorganic Chemistry; Li2B4O7; Organic Chemistry; Physical Chemistry; 介稳相图; 四元体系; 固体; 水合物; 液体; 物理化学性质; 相平衡
• ISSN: 1005-9040; 2210-3171
• DOI: 10.1007/s40242-017-6404-7

The metastable phase equilibria of the Li＋, Mg2＋//SO42-, borate-H2O system at 273.15 K were studied using isothermal evaporation method. The dry-salt phase diagram, water-phase diagram and the physicochemical property diagrams of the system were plotted with the metastable solubility values and physicochemical properties corresponding to density, refractive index, pH value and conductivity. The dry-salt diagram was composed of four crys- tallizing zones[lithium sulfate hydrate（Li2SO4·H2O）, epsomite（MgSO4·7H2O）, lithium metaborate octahy- drate（LiBO2.8H2O）, and hungchaoite（MgB4O7·9H2O）], five univariant curves and two invariant points （Li2SO4·H2O＋MgSO4·7H2O＋MgB4O7·9H2O and Li2SO4·H2O＋LiBO2-8H2O＋MgB4O7·9H20）. Li2B4O7 converted in- to LiBO2 in solution. Comparing the metastable phase diagram at 273.15 K and stable phase diagram at 298.15 K for the system, the crystallized area of Li2SO4·H2O and MgSO4·7H2O became large, whereas, the other phase regions became small. The J（H2O） changes regularly with increasing J（SO42-）, and the physicochemical properties change regularly with the concentration of B4O72- increasing.