Phase Equilibrium of (NH4Cl + MgCl2 + SrCl2 + H2O) and (LiCl + MgCl2 + SrCl2 + H2O) Systems at 313.15 K

The phase equilibria of the quaternary NH4Cl + MgCl2 + SrCl2 + H2O and LiCl + MgCl2 + SrCl2 + H2O systems at 313.15 K were checked using the isothermal solution equilibrium method, and the corresponding phase diagram was thus obtained. In the quaternary NH4Cl + MgCl2 + SrCl2 + H2O system, two non-variant points and four crystallization regions were determined. These regions include the crystallization of NH4Cl, MgCl2·6H2O, and SrCl2·6H2O, together with the double salt, which was identified as NH4Cl·MgCl2·6H2O. In contrast, the system (LiCl + MgCl2 + SrCl2 + H2O) exhibits three non-variant points and five crystallization regions: LiCl·H2O, MgCl2·6H2O, SrCl2·6H2O, SrCl2·2H2O, and double salt LiCl·MgCl2·7H2O. The results of experiments on these quaternary systems are importance for the separation and purification of minerals found in the oilfield brine in the Nanyishan region, Qaidam Basin.