Solid–Liquid Equilibria in the Ternary Systems LiCl–MgCl₂–H₂O and SrCl₂–MgCl₂–H₂O at 333 K

Abstract

The stable phase equilibrium of the two ternary systems LiCl−MgCl 2 −H 2 O and SrCl 2 −MgCl 2 −H 2 O at 333 K were researched by using the isothermal dissolution equilibrium method. The solubilities of salts in the equilibrium solution were determined, and the equilibrium solids were also investigated by using the Schreinemaker method. In the ternary system LiCl− MgCl 2 −H 2 O at 333 K, the phase diagram of the system is composed of two invariant points, three univariate curves, and three crystallization regions corresponding to MgCl 2 •6H 2 O, LiCl• H 2 O, and double salt LiCl•MgCl 2 •7H 2 O, no solid solution was found in the phase diagram. In the ternary system SrCl 2 −MgCl 2 − H 2 O at 333 K, there are two invariant points, three univariate solubility curves, and three crystallization areas corresponding to SrCl 2 •6H 2 O, SrCl 2 •2H 2 O, and MgCl 2 •6H 2 O; this system belongs to hydrate type II, and neither double salts nor solid solutions were formed.

Solid–Liquid Phase Equilibria in the Ternary MgCl2–NiCl2–H2O System at 303–323 K

“…Several studies have investigated other systems containing MgCl 2 . For example, Wang et al studied ternary LiCl + MgCl 2 + H 2 O and Li 2 SO 4 + MgSO 4 + H 2 O systems at 288.15 K. Gao et al studied ternary MgCl 2 + SrCl 2 + H 2 O systems and quaternary NaCl + MgCl 2 + SrCl 2 + H 2 O and KCl + MgCl 2 + SrCl 2 + H 2 O systems at 373 K. Zhao et al studied ternary LiCl–MgCl 2 –H 2 O and SrCl 2 –MgCl 2 –H 2 O systems at 333 K. Notably, the findings of these studies can provide guidance for the separation of magnesium and lithium from salt lake brine and the utilization of salt lake resources. − …”

Phase Equilibria of Quaternary Systems Containing the Chlorides of Ammonium, Strontium(Magnesium), and Aluminum at 298.2 K

“…Until now, there have been some experimental and theoretical studies which relate to the hexacomponent system NH 4 Cl–MgCl 2 –CaCl 2 –SrCl 2 –AlCl 3 –H 2 O, as described below: binary systems of SrCl 2 –H 2 O at 252.2–524.2 K, CaCl 2 –H 2 O at 239.2–523.2 K, and MgCl 2 –H 2 O at 223.2–503.2 K; ternary systems of MgCl 2 –CaCl 2 –H 2 O at 273.2–368.2 K, − CaCl 2 –SrCl 2 –H 2 O at 288.2–387.2 K, − MgCl 2 –SrCl 2 –H 2 O at 288.2–373.2 K, − NH 4 Cl–CaCl 2 –H 2 O at 273.2–348.2 K, − AlCl 3 –CaCl 2 –H 2 O at 278.2–363.2 K, , NH 4 Cl–MgCl 2 –H 2 O at 273.2–308.2 K, − AlCl 3 –SrCl 2 –H 2 O, NH 4 Cl–AlCl 3 –H 2 O, MgCl 2 –AlCl 3 –H 2 O at 298.2 K; quaternary systems of NH 4 Cl–CaCl 2 –AlCl 3 –H 2 O at 283.2–353.2 K, , MgCl 2 –SrCl 2 –AlCl 3 –H 2 O at 298.2 K, and NH 4 Cl–MgCl 2 –SrCl 2 –H 2 O at 298.2 K . The results show that (1) the solid solutions [(Ca, Sr)­Cl 2 ]·6H 2 O and [(Sr, Ca)­Cl 2 ]·6H 2 O are formed in the chloride-type system with the coexistence of strontium and calcium; (2) when magnesium chloride coexists with calcium or ammonium, it is easy to form double salts 2MgCl 2 ·CaCl 2 ·12H 2 O and NH 4 Cl·MgCl 2 ·6H 2 O; (3) strontium chloride can form into various hydrated salts at different temperatures, such as SrCl 2 ·6H 2 O, SrCl 2 ·2H 2 O, and SrCl 2 ·H 2 O; (4) the crystallization form of strontium chloride is also related to the coexisting ions, when MgCl 2 salt coexists with SrCl 2 ·6H 2 O at 298.2 K, both SrCl 2 ·6H 2 O and SrCl 2 ·2H 2 O exist in the systems of MgCl 2 –SrCl 2 –H 2 O and SrCl 2 –NH 4 Cl–MgCl 2 –H 2 O at 298.2 K. As for the quaternary systems NH 4 Cl–SrCl 2 –AlCl 3 –H 2 O and NH 4 Cl–MgCl 2 –AlCl 3 –H 2 O, they are the basic subsystems of the hexacomponent system NH 4 Cl–MgCl 2 –CaCl 2 –SrCl 2 –AlCl 3 –H 2 O, and the ternary subsystems NH 4 Cl–SrCl 2 –H 2 O, NH 4 Cl–MgCl 2 –H 2 O, AlCl 3 –SrCl 2 –H 2 O, NH 4 Cl–AlCl 3 –H 2 O, and MgCl 2 –AlCl 3 –H 2 O of these two quaternary systems at 298.2 K have been done by our previous works, while there is scarcely any literature about the phase equilibria of these two quaternary systems.…”