Solid–Liquid Metastable Equilibria of the Reciprocal Quaternary System (LiCl + MgCl2 + Li2SO4 + MgSO4 + H2O) at 323.15 K

• Published in: Journal of chemical and engineering data 2011-12, Vol.56 (12), p.4627-4632
• Main Authors: Meng, Lingzong, Yu, Xiaoping, Li, Dan, Deng, Tianlong
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Liquid-solid equilibria; Phase equilibria
• ISSN: 0021-9568; 1520-5134
• DOI: 10.1021/je200563j

Experimental studies on the metastable solubilities and the physicochemical properties (density, pH value, conductivity, and viscosity) of the aqueous reciprocal quaternary system (LiCl + MgCl2 + Li2SO4 + MgSO4 + H2O) at 323.15 K were determined with the isothermal evaporation method. According to the experimental results, the dry-salt phase diagram, water-phase diagram, and the physicochemical properties versus composition diagram were plotted. It was found that there are four invariant points, nine metastable solubility isotherm curves, and six metastable crystallization fields corresponding to lithium chloride monohydrate (LiCl·H2O), bischofite (MgCl2·6H2O), starkeyite (MgSO4·4H2O), hexahydrite (MgSO4·6H2O), lithium sulfate monohydrate (Li2SO4·H2O), and the double salt lithium-carnallite (LiCl·MgCl2·7H2O). No solid solution was found. On the basis of the extended Harvie–Weare (HW) model and its temperature-dependent equation, the values of the Pitzer parameters β(0), β(1), β(2), and C ø for Li2SO4, MgCl2, and MgSO4, the mixed ion-interaction parameters θLi,Mg, θCl,SO4 , ΨLi,Mg,Cl, ΨLi,Mg,SO4 , ΨLi,Cl,SO4 , and ΨMg,Cl,SO4 , and the Debye–Hückel parameter A ø of the quaternary system at 323.15 K were obtained. The calculated solubility of the quaternary system (LiCl + MgCl2 + Li2SO4 + MgSO4 + H2O) at 323.15 K was done. A comparison between the calculated and the experimental results shows that the predicted solubility agrees well with the experimental data.