Solid−liquid phase equilibria of the quinary system containing lithium, sodium, calcium, strontium and chloride ions at 273.15 K and 101.325 kPa

Abstract

The solid–liquid phase equilibria of systems LiCl–NaCl–CaCl2–SrCl2–H2O and CaCl2–SrCl2–H2O at 273.15 K and 0.1 MPa were investigated with the isothermal equilibrium method. The solid–liquid equilibrium phase diagrams were constructed with the experimental solubilities. The phase diagram in the ternary system consists of one univariant solubility curve saturated with solid solution (Ca,Sr)Cl2·6H2O, and one crystallization field of the solid solution. There are three invariant points, seven isothermal univariant curves, and five crystallization regions saturated with NaCl corresponding to (Ca,Sr)Cl2·6H2O, SrCl2·2H2O, LiCl·2H2O, CaCl2·4H2O and LiCl·CaCl2·5H2O in the dry-salt diagram of the quinary system. The areas of crystallization zones decrease according to the above order. The J(NaCl), J(H2O), refractive index and density of the solution gradually change regularly with the increasing of J(CaCl2) in the solution. These results on phase diagrams of the quinary system can supply theoretical reference for lithium salts and strontium salts separation from calcium chloride type brine.