四元含锂铷氯化物水盐体系298.2 K介稳相平衡研究

Study on the metastable phase equilibria of the aqueous quaternary system lithium rubidium chloride at 298.2 K

摘要:

采用等温蒸发法研究了四元含锂铷氯化物体系Li+, Na+, Rb+ // Cl- H2O 298.2 K下的相平衡关系，测定了平衡液相的溶解度、密度和折光率。基于实验数据，绘制了该四元体系的立体图、干基图、密度-组成图和折光率-组成图。该四元体系298.2 K下的介稳相图由一个共饱和点，三条单变量曲线和三个结晶区（RbCl、NaCl、LiCl·H2O）组成。将研究的结果同LiCl + KCl + RbCl + H2O体系进行了对比和分析，总结Na+ 和K+ 对三元体系Li+, Rb+ // Cl- H2O 的影响。应用折光率计算的经验公式对实验测定的折光率进行了验证，其最大绝对误差小于-0.0090，从而证明了实验数据的可靠性。

Abstract:

In this paper, the phase equilibria of the Li+, Na+, Rb+ //Cl- ‑ H2O with quaternary lithium rubidium chloride system at 298.2 K was studied by isothermal evaporation method, and the solubilities, densities and refractive indices of the equilibrated solution were determined experimentally. On the basis of the measured data, the stereo phase diagram, the dry-salt phase diagram, the density vs composition diagram and the refractive index versus composition diagram were constructed. Results show that the quaternary metastable phase diagram at 298.2 K consists of one invariant point, three univariant curves, and three crystallization fields corresponding to single salts potassium chloride (NaCl), rubidium chloride (RbCl), lithium chloride monohydrate (LiCl·H2O). the phase diagrams of the quaternary system Li+, Na+, Rb+ // Cl- - H2O and Li+, K+, Rb+ // Cl- - H2O at 298.2 K were compared and analyzed, and the effects of Na+ and K+ in the three system Li+, Rb+ // Cl- ‑ H2O were summarized. Using the empirical formula of refractive index calculation to the theoretical value of refractive index, the maximum absolute error between the calculated and experimental data is less than -0.0090, which proves the reliability of the experimental data.