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

Abstract

The phase equilibria of the quaternary systems NH 4 Cl−SrCl 2 −AlCl 3 −H 2 O and NH 4 Cl−MgCl 2 −AlCl 3 −H 2 O at 298.2 K were investigated by using the isothermal dissolution method. The solubility, density, and refractive index of the systems were measured experimentally, and the related phase diagrams, density/refractive index versus composition diagrams, are plotted. There is one quaternary invariant point and three crystallization regions corresponding to single salts NH 4 Cl, AlCl 3 •6H 2 O, and SrCl 2 •6H 2 O in the phase diagram of the system NH 4 Cl−SrCl 2 −AlCl 3 −H 2 O at 298.2 K, which belongs to a simple system. In addition to the single salts NH 4 Cl, AlCl 3 •6H 2 O, and MgCl 2 •6H 2 O, the double salt NH 4 Cl•MgCl 2 •6H 2 O is formed in the quaternary system NH 4 Cl−MgCl 2 −AlCl 3 −H 2 O at 298.2 K, which indicates that the addition of magnesium makes the interaction relationship between Al 3+ , NH 4+ , and Mg 2+ more complex and increases the difficulty of separation of magnesium. The crystallization region of NH 4 Cl is the largest in both the systems, which indicates that NH 4 Cl is much easier to separate than the other salts from the two systems.

Solid–Liquid Phase Equilibria of Aqueous Quaternary System Na+, K+, Mg2+//SO42––H2O at T = 298.2 and 323.2 K

“…The solid-phase composition of invariant point H 4 is Na 2 SO 4 ·MgSO 4 ·4H 2 O, K 2 SO 4 ·MgSO 4 ·6H 2 O, and Na 2 SO 4 ·3K 2 SO 4 ; the corresponding liquid phase composition is w (Na 2 SO 4 ) = 13.80%, w (K 2 SO 4 ) = 5.24%, and w (MgSO 4 ) = 17.33%. According to judgment rules of invariant points, the type of invariant points H 1 and H 3 are commensurate invariant point, while invariant points H 2 and H 4 are incommensurate invariant points.…”

Solid–Liquid Phase Equilibria Determination of Quaternary System NH4+, Mg2+, Ca2+//Cl––H2O at T = 298.2 and 323.2 K and p = 94.77 kPa

“…Accordingly, the phase equilibria of this quaternary system at 298.2 and 323.2 K are presented here in detail. In addition, our research group has also completed similar systems such as NH 4 + , Ca 2+ , Al 3+ //Cl – –H 2 O at 298.2 K; NH 4 + , Mg 2+ , Sr 2+ //Cl – –H 2 O at 298.2 K; and NH 4 + , Mg 2+ (Sr 2+ ), Al 3+ //Cl – –H 2 O, and the comparison of these two systems and NH 4 + , Mg 2+ , Ca 2+ //Cl – –H 2 O was done in this work.…”

Phase Equilibria of Aqueous Ternary Systems NH4Cl + CaCl2 + H2O and NH4Cl + MgCl2 + H2O at 308.2 K: Measurement and Calculation

“…Until now, the phase equilibria of aqueous salts containing ammonium at multiple temperatures have been reported. For example, there are only two crystallization regions of NH 4 Cl and LiCl·2H 2 O at 273.2 K in the ternary system LiCl + NH 4 Cl + H 2 O, while the crystallization region of the solid solution (NH 4 Cl) x (LiCl·H 2 O) 1– x is formed at 298.2 and 323.2 K. , The solid solutions (NH 4 Cl) x (KCl) 1– x and (NH 4 Cl) 1– x (KCl) x are formed in the system KCl + NH 4 Cl + H 2 O at 273.2, 283.2, 298.2, and 308.2 K. − The quaternary system NH 4 Cl + SrCl 2 + AlCl 3 + H 2 O and its ternary subsystems NH 4 Cl + SrCl 2 + H 2 O and NH 4 Cl + AlCl 3 + H 2 O at 298.2 K are simple types, neither a double salt nor a solid solution formed. − The quaternary system NaCl + KCl + NH 4 Cl + H 2 O at 323.2 K formed the solid solutions (NH 4 Cl) x (KCl) 1– x and (NH 4 Cl) 1– x (KCl) x . For the quaternary system NaCl + NH 4 Cl + MgCl 2 + H 2 O at 273.2, 298.2, 333.2, and 348.2 K, − the crystallization region of the double salt NH 4 Cl·MgCl 2 ·6H 2 O exists.…”