THE EQUILIBRIUM REACTION OF THE EXTRACTION OF URANIUM(VI) WITH DI-(2-ETHYLHEXYL) PHOSPHORIC ACID FROM NITRIC ACID SOLUTIONS

Abstract

ABSTRACT The equilibrium reactions for the extraction of uranium(VI) with di(2-ethylhexyl)phosphoric acid from nitric acid solutions is investigated. In this work, proton NMR technique was used to verify that the nitrate ligand in the resulting complexes originated from the complexing of nitric acid. Organic solutions of 0.05 M (dimeric HDEHP, the upper bar denotes the species in the organic phase) in kerosene were used to extract aqueous solutions containing various concentrations of uranyl nitrate and nitric acid. The concentrations of nitric acid and uranium(VI) in the organic phase were measured, and used to determine the composition of the resulting complex. Which were found to be varied with the uranium(VI) loading and the nitric acid loading of HDEHP. Parallel reactions of forming UO were proposed to describe this extraction system. The proposed reactions elucidate the equilibrium behavior consistently, for the loadings of uranium(VI) and nitric acid ranging from very low value to the vicinity of saturation.