Abstract: Solubilities and properties (density, conductivity and pH value) of solutions in the quaternary system Li⁺,K⁺//CO^2-₃,B₄O^2-₇-H₂O at 288 K were experimentally studied with the isothermal equilibrium method. The phase diagram of the system consisted of two invariant points E and F, five univariant curves, and four crystallization fields that belonged to K₂CO₃·3/2H₂O，Li₂B₄O₇·3H₂O，K₂B₄O₇·4H₂O and Li₂CO₃. The composition of the solution corresponding to E was w（CO^2-₃）=2.27 %，w（B₄O^2-₇）=6.05 %，w（K⁺ ）=4.30%，w(Li⁺)=0.30 % and the equilibrium solids were Li₂B₄O₇· 3H₂O+K ₂B₄O₇·4H₂O+Li₂CO₃;The composition of the solution for F was w(CO^2-₃)=22.45%，w(B₄O^2-₇)=1.88%，w(K⁺ )=29.96%，w(Li⁺ )=0.03% and the equilibrium solids were K₂CO₃·3/2H₂O+K ₂B₄O₇·4H₂O+Li₂CO₃. K₂CO₃ possesses strong salting-out effect on K₂B₄O₇,Li₂CO₃ and Li₂B₄O₇.

Key words: 水盐体系, 相平衡, 硼酸盐, 碳酸盐

关键词: 水盐体系, 相平衡, 硼酸盐, 碳酸盐