Fundamental Chemistry of Cesium Extraction from Acidic Media by HCCD in FS-13

• Published in: Solvent extraction and ion exchange Vol. 26; no. 2; pp. 163 - 174
• Main Authors: Scott Herbst, R., Peterman, Dean R., Tillotson, Richard D., Delmau, Lætitia H.
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis Group 01.03.2008
• Subjects: cesium; cesium extraction; chlorinated cobalt dicarbollide; Extraction; slope analysis; trifluoromethylphenyl sulfone
• ISSN: 0736-6299; 1532-2262
• DOI: 10.1080/07366290801925298

We previously published a model for cesium extraction from acidic media by the protonated form of the hexachlorinated derivative of the chloro-protected cobalt bis(dicarbollide), HCCD, dissolved in trifluoromethylphenyl sulfone, FS-13. The model indicated that Cs extraction proceeds through a series of ion-paired and/or dissociated extraction equilibria. Additional Cs distribution ratio data has been obtained and the model refined and simplified. It is demonstrated that the equilibrium exclusively involving the exchange of proton for cesium by formation of ion-paired CsCCD models the Cs distribution data very well, particularly for the concentrations of HCCD greater than ∼0.0005 M (0.5 mM). Finally, activity corrections for the aqueous phase to the Cs distribution data results in good agreement to the theoretical value of −1 for slope (log-log) analysis of the data over a wide range of HNO 3 and HCCD concentrations.