Stable Phase Equilibria in Quaternary LiCl–NaCl–MgCl₂–H₂O and NaCl–Na₂B₄O₇–MgCl₂–MgB₄O₇–H₂O Systems at 273 K

Abstract

Phase equilibria of quaternary LiCl–NaCl–MgCl₂–H₂O and NaCl–Na₂B₄O₇–MgCl₂–MgB₄O₇–H₂O systems at 273 K were studied by isothermal dissolution. The isothermal solubility of each salt was measured. Based on the experimental data and the corresponding equilibrium solid phases, equilibrium phase diagrams and water content diagrams were drawn. The results show that the quaternary LiCl–NaCl–MgCl₂–H₂O system forms a double salt LiCl·MgCl₂·7H₂O at 273 K. The phase diagram contains two invariant points, five univariant curves and four crystalline regions. The crystalline regions are LiCl·2H₂O, NaCl, MgCl₂·6H₂O and LiCl·MgCl₂·7H₂O, respectively. There are two invariant points, five univariant curves and four crystallizing fields in the quaternary NaCl–Na₂B₄O₇–MgCl₂–MgB₄O₇–H₂O system at 273 K, and the corresponding crystallizing fields are NaCl, Na₂B₄O₇·10H₂O, MgCl₂·6H₂O and MgB₄O₇·9H₂O.