Solid–Liquid Phase Equilibrium in the Quaternary System (LiCl + NaCl + KCl + H2O) at 288.15 K

Abstract

The solubilities in the quaternary system (LiCl + NaCl + KCl + H2O) at 288.15 K were investigated with the method of isothermal dissolution equilibrium. The phase diagram includes one cosaturated point, three isotherm dissolution curves, and three crystallization regions corresponding to sodium chloride, potassium chloride, and lithium chloride dihydrate. The area of the crystallization region of LiCl · 2H2O is the smallest, and it has a strong salting-out effect to NaCl and KCl. Comparing the phase diagrams of the quaternary system at 288.15 and 298.15, 373.15 K, it was found that solid mineral LiCl · 2H2O at 288.15 K transformed to LiCl · H2O at 298.15 K and LiCl at 373.15 K. Moreover, the area of the crystallization region of lithium chloride and sodium chloride increase with the increasing temperature, while that of potassium chloride decrease dramatically. Meanwhile, on the base of Pitzer model and its extended HW model, the solubilities in this quaternary system at 288.15 K were calculated and it shows that the predicted solubility result agree well with the experimental data.