Study On Equilibria In The Quinary Systems Li⁺, Na⁺, K⁺//SO₄^2-, B₄O₇^2--H₂O And Li⁺, K⁺//Cl^-, SO₄^2-, B

Phase equilibria of reciprocal quinary systems Li⁺, Na⁺, K⁺//SO₄^2-, B₄O₇^2--H₂O and Li⁺, K⁺//Cl^-, SO₄^2-, B₄O₇^2--H₂O and three quaternary systems at 288 K were studied by isothermal solution equilibrium method. Solubilities and densities in the solution of these systems were determined experimentally. According to the experimental data, the equilibrium phase diagrams, corresponding water content diagrams and density component diagrams of quaternary systems were finished. The phase diagrams, corresponding water content diagrams and density component diagrams of quinary systems at 288 K ( saturated with Li₂B₄O₇ ) were also plotted.The experimental results show that the quaternary system Na⁺, K⁺//Cl^-, B₄O₇^2--H₂O at 288 K was of simple eutectic type and no double salt or solid solution was found. In the phase diagram, the quaternary system has two invariant points, five univariant curves, four fields of crystallization [NaCl, KCl, Na₂B₄O₇·10H₂O and K₂B₄O₇·4H₂O].The quaternary system Li⁺, K⁺//Cl^-, B₄O₇^2--H₂O was of simple eutectic type and no double salt or solid solution was found also. In the phase diagram, the quaternary system has two invariant points, five univariant curves, four fields of crystallization [LiCl·H₂O, KCl, Li₂B₄O₇·3H₂O and K₂B₄O₇·4H₂O].The quaternary system Li⁺, Na⁺//Cl^-, B₄O₇^2--H₂O was of simple eutectic type and no double salt or solid solution was found still. In the phase diagram, the quaternary system has two invariant points, five univariant curves, four fields of crystallization [LiCl·H₂O, NaCl, Li₂B₄O₇·3H₂O, Na₂B₄O₇·10H₂O].In stable equilibrium phase diagram of quinary system Li⁺, Na⁺, K⁺//SO₄^2-, B₄O₇^2--H₂O at 288 K, there are seventeen uninvariant curves, nine invariant points, nine crystallization fields (saturated with Li₂B₄O₇): Na₂B₄O₇·10H₂O, K₂B₄O₇·4H₂O, K₂SO₄, Na₂SO₄·10H₂O, Li₂SO₄·H₂O, Na₂SO₄·3K₂SO₄, Li₂SO₄·3Na₂SO₄·12H₂O, KLiSO₄ and Na₂SO₄·K₂SO₄·2Li₂SO₄.In stable equilibrium phase diagram of quinary system Li⁺, K⁺// Cl^-, SO₄^2-, B₄O₇^2--H₂O at 288 K, there are nine uninvariant curves, four invariant points, six crystallization fields (saturated with Li₂B₄O₇): K₂B₄O₇·4H₂O, K₂SO₄, Li₂SO₄·H₂O, KCl, LiCl·H₂O and KLiSO₄.