Modelling of uranium extraction in sulphuric medium

A cationic extractant, 2-ethyl hexyl-phosphonic acid (PC88A), has been studied to recover uranium from conventional ore by solvent extraction. On the basis of experimental studies, extraction equilibria for uranium in sulphuric medium with PC88A were suggested. Then, an extraction model was developed. Uranium speciation in the aqueous phase had to be established and the medium effects were taken into account according to the Specific Interaction Theory (SIT). Extraction equilibrium constants were determined by optimization. Thanks to this theory, the model does not depend on the experimental conditions and it was validated on a wide range of sulphate concentrations and acidities. (authors)