Extraction of nitric acid and uranyl nitrate with tributyl phosphate in diluent in the presence of salting-out agents and its mathematical description

Abstract

Database on separate and joint extraction of uranyl nitrate and nitric acid with 30% and 15% TBP in paraffin diluent in the presence of salting-out agents (sodium, magnesium, calcium, aluminum, and iron nitrates) is presented. The effect of the salting-out agents fits in the previously suggested mathematical description of these extraction equilibria without salting-out agents using the law of mass action and the previously suggested system of 11 equations with the corresponding concentration equilibrium constants without additional empirical corrections, but with recalculation of the concentrations of the aqueous phase components taking into account the molar volume of the salting-out agent in solution. With aluminum nitrate, it is also necessary to take into account its possible hydrolysis with variation of the calculated concentration of hydrated proton, but at an Al(NO3)3 concentration of 1 M without free HNO3 this correction is insufficient because of possible extraction of HNO3 produced by hydrolysis and of the shift of the extraction system to the region of acid-deficient aqueous solutions.