The phase equilibria of the ternary system at 298.15 and 338.15 K were investigated by the isothermal dissolution equilibrium and wet-reside solid phase (Schreinemarkers rule) methods. The solubilities and the physicochemical properties containing density and refractive index were obtained experimentally. Then, the phase diagrams and the diagrams of physicochemical properties against the composition in the ternary system at two temperatures were proposed. The phase diagrams of this system at two temperatures contain two invariant points, three solubility curves, and three crystallized regions corresponding to NaNO₃, RbNO₃ and double salt NaRb₂(NO₃)₃. According to the phase diagrams at 298.15 and 338.15 K, a novel separation process of RbNO₃ from the mixture solution of NaNO₃ was established for the first time, and the separation rate of RbNO₃ in the mixed solution reached 43.75% in a single yield. This work provides an efficient and reliable RbNO₃ green recovery method from the eluent solution of NaNO₃ efficiently.

通过等温溶解平衡和湿残留物固相（Schreinemarkers 规则）方法研究了三元系统在 298.15 和 338.15 K 的相平衡。溶解度和包括密度和折射率在内的物理化学性质是通过实验获得的。然后，提出了在两个温度下三元体系中的相图和物理化学性质与组成的关系图。该体系在两个温度下的相图包含两个不变点、三个溶解度曲线和三个分别对应NaNO ₃、RbNO ₃和复盐NaRb ₂ (NO ₃ ) _{3的结晶区}. 根据298.15和338.15 K相图，首次建立了从NaNO 3 混合溶液中分离RbNO ₃的新工艺，单_次收率达到43.75%。 . 本工作提供了一种高效可靠的从NaNO ₃洗脱液中高效回收RbNO ₃绿色的方法。