Modelling of the extraction of uranium with supercritical carbon dioxide

A model is presented for the analysis of the results of extraction of uranium in a flow system by supercritical fluid modified with tributylphosphate from a nitric acid matrix, in which the extraction is not limited by the solubility of the uranium species. The model used is that of diffusion out of a sphere into a medium in which the extracted uranium is infinitely dilute. Although not a completely accurate representation of the liquid-supercritical fluid system, the model is shown to be a reasonable representation and some conclusions discussed.