Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

With the isothermal dissolution equilibrium method and wet-residue method, the solubility data as well as physicochemical properties including density, refractive index and pH value of the two ternary systems (NaCl + NaBO2 + H2O) and (Na2SO4 + NaBO2 + H2O) at 298.15 K and 0.1 MPa have been experimentally determined, and the relatively phase diagrams have been established for the first time. In the ternary system (NaCl + NaBO2 + H2O), two invariant points, three univariant curves, and three crystallization regions corresponding to sodium chloride (NaCl), sodium metaborate tetrahydrate (NaBO2*4H2O) and a congruent double salt teepleite (NaCl*NaBO2*2H2O) were detected. While in the ternary system (Na2SO4 + NaBO2 + H2O), there are one invariant point, two univariant curves, and two crystallization regions corresponding to NaBO2*4H2O and mirabilite (Na2SO4*10H2O). The physicochemical properties (density, refractive index and pH value) in the two systems present a regular variation versus with the changes of sodium metaborate concentration in the solution. Moreover, on the basis of empirical equations of refractive index and density, the calculated values of refractive index and density are in consistent with the experimental data.