Extraction of Uranium by Trioctylamine

Abstract

The purpose of this research is to elucidate the mechanism of the extraction of uranium by trioctylamine in benzene. The extraction equilibria of uranyl ( VI) nitrate were investigated in an aqueous solution of nitric acid, whose concentration being less than 6 mol/l. The extraction rates of uranyl(VI) nitrate in 3 mol/l nitric acid solution were measured by using a stirring cell with a flat liquid-liquid interface, and analyzed in terms of a simple model.
The distribution equilibrium could be expressed by the following equation upon considering the extraction reaction, in which one mole of UO₂ (NO₃)2 associates with two moles of amine nitrate (R3NHNO₃):
where n=2, Ka = 2.20, 81= 5.0, 1/2= O.001, K= 5.50 x 10^-4.
It was found that the extraction rates could approximately be expressed by the model, in which UO₂NO₃⁺ alone, as an uranyl complex in an aqueous phase, and an electric field were considered.