METHOD OF DETERMINING EXTRACTANT-NITRIC ACID SYSTEM STABILITY Russian patent published in 1999 - IPC

FIELD: radioactive compounds technology. SUBSTANCE: method can be used in extraction processing of uranium solutions and in selecting extraction systems assuring safe process conditions. Stability of extractant-nitric acid systems is determined from degree of extractant-nitric acid interaction involving fixed-temperature heat treatment of samples with different initial concentrations of nitric acid in aqueous phase and equilibrium concentration of nitric acid in extractant. For each temperature, equilibrium concentrations of nitric acid in aqueous phase corresponding to starting interaction are determined and curve for temperature dependence of these equilibrium concentrations is plotted, this dependence being indicative of stability region. Values of above equilibrium concentrations are found in points obtained by extrapolation to abscissa of linear sections of curves depicting dependence of optical density of solution colored by nitro compound of thermally treated extractant on equilibrium concentration of nitric acid in aqueous phase. Solution for determining optical density is prepared by adding thermally treated extractant aliquot to alcohol solution containing 0/1 M KOH. EFFECT: widened stability region of extraction systems in presence of hydrolizable impurities. 2 cl, 3 dwg, 2 ex