Monday, June 18, 2007 - 11:05 AM
The Peregrins (Boise Centre on the Grove)

Effect of Acetohydroxamic Acid on Distribution of Pu(IV) in 30% TBP

Alena Paulenova and Peter Tkac. Oregon State University, Corvallis, OR

The effect of acetohydroxamic acid (AHA) on speciation of tetravalent plutonium has been investigated in chemical matrices relevant to UREX+ extraction process. The extraction experiments were focused on effect of HNO3, total nitrate and AHA concentration on extraction of Pu(IV) by tributyl phosphate. Significantly decreased extraction yields of plutonium confirm a strong affinity of AHA to tetravalent plutonium even under strong acidic conditions of the aqueous nitric acid/nitrate matrix. Kinetics of plutonium redox reactions and complexation with AHA are the most important factors affecting the extraction performance of the process. Spectrophotometric speciation experiments performed with both the aqueous and organic extraction phase confirmed penetration of hydroxamate species of plutonium in the organic phase and formation of neutral solvates of tributyl phosphate with ternary hydroxamate-nitrate complexes of metal.