1985 Volume 11 Issue 3 Pages 267-271
Vapor-liquid equilibria (VLE) for the systems HNO3-H2O, HNO3-H2O-Mg(NO3)2 and HNO3-H2O-Ca(NO3)2 were measured at 101.3 kPa. The vapor pressures of aqueous solutions of Mg (NO3) 2 and Ca (NO3) 2, which were necessary for correlation of ternary VLE data, were also measured. From the two ternary VLE data, it was found that the salting-out effect of magnesium salt was larger than that of calcium salt and that the mole fraction of HNO3 in the azeotropic mixture decreased linearly with increasing salt concentration.
The VLE data for the ternary systems were well correlated by use of the method proposed by the authors. The calculated results of the vapor phase composition and boiling point were in good agreement with the experimental data.
