Metastable Phase Equilibria of the Reciprocal Quaternary System Containing Sodium, Potassium, Chloride, and Borate Ions at 308.15 K
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- 作者：Tianlong Deng ; Lingzong Meng ; Bai Sun
- 刊名：Journal of Chemical & Engineering Data
- 出版年：2008
- 出版时间：March 2008
- 年：2008
- 卷：53
- 期：3
- 页码：704 - 709
- 全文大小：832K
- 年卷期：v.53,no.3(March 2008)
- ISSN：1520-5134
文摘
The metastable solubility of the reciprocal quaternary system containing sodium, potassium, chloride, and borate ions and the physicochemical properties corresponding to density, viscosity, pH value, and refractive index at 308.15 K have been studied with the isothermal evaporation method. According to the experimental data, the metastable equilibrium phase diagrams of dry salt and the water phase diagram of the system were plotted. In the dry-salt phase diagram, there are two invariant points, five univariant curves, and four crystallizing regions corresponding to sodium chloride, potassium chloride, borax (Na2B4O7·10H2O), and potassium tetraborate tetrahydrate (K2B4O7·4H2O). The crystallized region of borax is the largest, while the phase region of NaCl is the smallest with the highest concentration and a strong salting-out effect to borax. There are neither double salts nor solid solutions formed in the metastable system. When compared with the stable phase diagram at 298.15 K of the system, the areas of both metastable phase regions of borax and potassium chloride are enlarged, while other metastable phase regions are decreased. The calculated values of densities and refractive index in the metastable quaternary system with the empirical equations are in good agreement with the experimental values.