Uranium Extraction from Phosphoric Acid Using Bifunctional Amido-Phosphonic Acid Ligands

Abstract

Ligand systems containing amido-phosphonic acid moieties were synthesized for subsequent U(VI) extraction from phosphoric acid solutions. Studies have shown that the efficiency of extraction (distribution ratios and selectivity of U(VI) over Fe(III)) is influenced by the nature of the N-dialkyl substituents and the length and nature of the spacer. A structure-activity approach resulted in the identification of a specific ligand called DEHCBPA that exhibited larger D-values than the corresponding URPHOS reference system. The distribution ratios for U(VI) extraction increased considerably with a branched N-dialkyl chain when a steric hindrance was introduced into the methylene bridge of the amido-phosphonic acid ligands.

Keywords:

• Bifunctional extractants
• carbamoylphosphonic acid
• uranium extraction
• phosphoric acid
• selectivity

ACKNOWLEDGMENTS

The authors would like to acknowledge and thank Jean-Charles Gaillard (CEA-DSV-IBEB-SBTN-LBSP) for providing the HRMS measurements.

FUNDING

This work was financed by AREVA Mines through the NOPRA project. The authors would also like to acknowledge the CEA, CNRS and UM2 for their support.

SUPPLEMENTARY MATERIAL

Supplemental data for this article can be accessed on the publisher’s website: www.tandfonline.com/lsei