三元体系K +,Cs +//SO4 2——H2O 298.2 K稳定相平衡研究

采用等温溶解法开展了三元体系K ⁺,Cs ⁺//SO₄ ^2--H₂O 298.2 K稳定相平衡研究,测定了该体系溶解度、密度及折光率。结果表明,该三元体系在298.2 K下属于复杂体系,有固溶体（K,Cs）₂SO₄产生,且固溶体相区最大;其稳定相图包含3条单变量曲线、3个析出相区和2个共饱点;共饱点处对应的液相组成分别为w（K₂SO₄）=11.69%、w（Cs₂SO₄）=4.02%和w（K₂SO₄）=3.39%、w（Cs₂SO₄）=60.84%。平衡液相的密度和折光率随Cs₂SO₄含量的增大呈现递增的趋势。采用经验公式对平衡液相的折光率进行理论计算,计算值和实验值具有良好的一致性。

Stable phase equilibrium of the ternary system K +,Cs +//SO4 2--H2O at 298.2 K

The stable phase equilibrium of the ternary system K ⁺,Cs ⁺//SO₄ ^2--H₂O has been studied using the isothermal dis-solution method at 298.2 K.The solubilities,densities and refractive indices of the equilibrated solution were determined experimentally.The results showed that the ternary system was of complex type with solid solution [（K,Cs）₂SO₄] formed at 298.2 K,and with the largest crystalline region for the solid solution [（K,Cs）₂SO₄].The stable phase diagram of this ternary system contained three univariant curves,three crystalline zones and two invariant points.The mass fraction composition of the two invariant points were w（K₂SO₄） 11.69%、w（Cs₂SO₄） 4.02% and w（K₂SO₄） 3.39%、w（Cs₂SO₄） 60.84%,respectively. The density and refractive index of the solution increased along with the increase of the Cs₂SO₄ contents.Furthermore,the empirical equation developed in the previous study was used to calculate refractive index of the equilibrated solutions,the calculated values results indicated good consistency with the experimental values.