Solid-Liquid Phase Equilibria of the Quinary System Containing Lithium, Sodium, Calcium, Chloride, and Borate Ions at T=288.15 K and p=101.325 kPa

The solid-liquid phase diagram of salt-water systems containing lithium, calcium, and borate is of significance to understand the thermodynamic properties of the electrolytes and promote the productions of lithium and calcium borates. Solubilities and physicochemical properties including density and refractive index of the quinary system (Li+, Na+, Ca2+//Cl-, borate-H2O) at 288.15 K and 0.1 MPa were investigated by the isothermal dissolution equilibrium method for the first time in this work. The dry-salt, the water-phase, and the sodium-phase diagrams were plotted. In the dry-salt diagram, there are four invariant points, nine isothermal univariant curves, and six crystallization regions (all saturated with NaCl), and no solid solution was found in the system. With a view of the crystallization region, the areas of crystallization regions of minerals are in the order of Na2B4O7 center dot 10H(2)O > CaB6O10 center dot 5H(2)O > Li2B4O7 center dot 3H(2)O > LiCl center dot CaCl2 center dot 5H(2)O > CaCl2 center dot 6H(2)O > LiCl center dot 2H(2)O, namely, the solubility of borax is the lowest and could be the first crystallized-out mineral with halite. Corresponding physicochemical properties including density and refractive index of the quinary system at 288.15 K were regularly changed with the Janecke index of calcium J(Ca2+) in the solution.