Studies on Phase Equilibria in the Quaternary Systems LiCl-KCl -MgCl2-H2O and Li2B4O7-Na2B4O7-MgB4O7-H2O at 273 K

The stable phase equilibria of the quaternary systems LiCl-KCl-MgCl2-H2O and Li2B4O7-Na2B4O7-MgB4O7-H2O at 273 K were studied using isothermal stable equilibrium method and the solubilities of the salts in the systems were also determined in turn. According to the experimental data and the corresponding equilibrium solid phases, the isothermal solubility diagrams, water content diagrams about two systems at 273 K were plotted, respectively. The first system has two double salts LiCl-MgCl2 center dot 7H(2)O and KCl center dot MgCl2 center dot 6H(2)O at 273 K, and its isothermal phase diagram of this system includes three invariant points, seven univariate curves, and five crystalline areas, those are LiCl center dot 2H(2)O, MgCl2 center dot 6H(2)O, KCl, LiCl center dot MgCl2 center dot 7H(2)O and KCl center dot MgCl2 center dot 6H(2)O, respectively. The second system has no complex salt or solid solution and the system belongs to a simple cosaturated type, and its stable phase diagram is constituted by an invariant point, three univariant solubility curves, and three solid phase crystalline regions, where the three solid phases crystalline regions are Li2B4O7 center dot 3H(2)O, K2B4O7 center dot 4H(2)O, and MgB4O7 center dot 9H(2)O, respectively.