Vapour-liquid and liquid-solid equilibria in the system Th(NO3)4-UO2(NO3)2-HNO3-H2O

Vapour-liquid and liquid-solid equilibria were studied in the system Th(NO3)4-UO2(NO3)2-HNO3-H2O. Hexahydrate of thorium nitrate as well as hexa- and trihydrate of uranyl nitrate were supposed to be formed in this system. Empiric equations of solubility isotherms were derived for 25 deg C and liquid phase densities were determined. It was established that nitric acid was salted out into the vapour phase by the nitrates present in the system both separately and simultaneously. Empiric equation was derived that describes the relationship between the HNO3 concentration of condensate and that of all liquid phase components. (author)