Calculation of Phase Equilibria in the Th(NO3)4-HNO3-H2O System at 25°C

Abstract

Pitzer's binary parameters of thorium nitrate were calculated from critically selected published data on the water vapor pressure in the Th(NO3)4-H2O system at 25°C. From data on the water vapor pressure in the Th(NO3)4-HNO3-H2O ternary system, the Pitzer's ternary parameters were calculated at 25°C. The branch of thorium nitrate hexahydrate crystallization in the ternary system was calculated in the region from 0 to 15 m HNO3 using complete set of Pitzer's binary and ternary parameters. The calculation results coincide with the experimental data on the solubility.