Studies on Extraction of Hexavalent Uranium by Cyanex-923 with Some Synergistic Ligands

Abstract

In the present study the systems involving Cyanex-923 as a synergist in the extraction of uranium(VI) using  Cyanex-272,TPBD,TNBD,TOPO and their mixtures has been investigated in xylene. Analysis of the extraction data by both graphical and theoretical methods by taking into account complexation  of the metal ion in the aqueous phase with inorganic ligands and all plausible complexes extracted into the organic phase. The metal ion is extracted into xylene as UO₂(NO₃)₂ .2TRPO.  Infrared spectral data of the extracted complexes have been used to further clarify the nature of the complexes. At given extractant concentration (pH 3), the extraction of U(VI) increases with nitrate concentration. The slope of the plot log D (where D is the distribution coefficient defined as the ratio of concentration of metal in the organic phase to that present in the aqueous phase) against log [NO₃^-] is nearly 2 indicating the extraction of neutral species into organic phase. Mixed species of the type UO₂(NO₃)₂.2TRPO.2S and UO₂(NO₃)₂.2TRPO.S were obtained with mixtures of Cyanex-923 and S( where S=   Cyanex-272,TOPO  ) may be responsible for the synergism.