EVALUATION OF EXCESS VOLUME IN UO2(NO3)(2)CENTER-DOT-6H(2)O-HNO3-H2O TERNARY MIXTURE

In order to obtain the exact information of atomic number density in U O2(NO3)(2).6H(2)O-HNO3-H2O ternary mixture, the theoretical estimation of excess volume which is one of excess properties of non-ideal solut ion is discussed in this study. The calculation model based on the Sto kes-Robinson application of the Brunauer-Emmett-Teller (BET) adsorptio n isotherm and activity equations of water, nitric acid, and uranyl ni trate hexahydrate (UNH) which were used to calculate distribution coef ficients in a solvent extraction system has one adjustable parameter a nd two BET constants. The BET constants have been determined by asympt otic method on tile BET adsorption isotherm as a function of water act ivity in the ternary system. As results of tile study, the observed vo lume of mixture agrees with the volume predicted by the simulation wit hin a maximum relative deviation of 0.78% and the excess volume is als o estimated as a fuller ion of total molality.