Phase equilibria and phase diagrams for the aqueous ternary system containing potassium, chlorine and metaborate ions at 298.15 and 323.15 K and 101.325 kPa

Abstract

Equilibria data and the physicochemical properties including density and refractive index for the ternary system (KCl + KBO2 + H2O) at 298.15 and 323.15 K were determined and proposed with the isothermal dissolution equilibrium and wet-reside solid phase (Schreinemarkers rule) methods. Also, the phase diagram and chart of physicochemical properties were constructed based on experimental data. For both temperatures, one invariant point, two univariant curves, two crystallization regions corresponding to KCl and KBO2·4/3H2O were found. Noticeably, with the rise of temperature, the solubilities of the single salts of KCl and KBO2·4/3H2O become large; meanwhile, the solubilities data at the invariant point also increase. What’s more, the physicochemical properties, including density and refractive index, change systematically in the wake of the concentration of potassium chloride, and due to the increase of solubilities along with the augment of temperature, the density and refractive index at 323.15 K have been increased compared at 298.15 K. The calculated values of the density and refractive index correlated using the empirical equations were consistent with the experimental data and the parameters obtained in our work are authentic.