The Effects of Nitric Acid on Extraction Properties of TODGA During Fission Product Management

ABSTRACTIn the context of management of the wastes arising from the reprocessing of spent nuclear fuel, studies have been conducted into the solvent extraction kinetics of lanthanide fission products by TODGA and the effects of solvent phase acidity on the effectiveness of this organic extractant molecule. In this study we observe an increase in organic phase viscosity increasing acidity and, potentially by consequence, that the rate of cerium extraction is summarily decreased.

A study of cerium extraction by TBP and TODGA using a rotating diffusion cell

For the study of the coupled interfacial-mass transfer kinetics of, inter alia, TBP, TODGA, CyMe4-BTBP and CyMe4-BTPhen based solvent extraction processes, a new rotating diffusion cell (RDC) apparatus has been established at Lancaster University. RDC studies of Ce(IV)/TBP and Ce(III)/TODGA extraction systems have been undertaken in order to improve the understanding of the chemical and kinetic processes involved. In each case, an interesting dependency on local hydrodynamics at the solution phase boundary with results suggesting that the organic extractant molecules migrate into the aqueous phase in order to capture Ce.

Effect of Contact with Organic Extractant LIX 84IC during Solvent Extraction Process on the Re-Establishment of Growth of Bioleaching Microorganisms

Solvent extraction (SX) used for the recovery of copper is a primary low-cost hydrometallurgical process applied extensively in cases like commercial bioleaching operations. Bioleaching solutions during SX treatment are exposed to important concentrations of organic extractants, a step that has a detrimental impact on microbial activity. The following work studies and determines the effect of this exposure on the re-establishment of growth and activity of different bioleaching microorganisms after contact and phase separation. Different bioleaching iron and sulfur -oxidizing microorganisms were tested. After contact with an industrially utilized organic extractant (LIX 84IC as extractant and Oxform SX12 as solvent), cultures were grown and their substrate utilization monitored.Acidithiobacillus ferrooxidansshowed only a slight increase in doubling time without significant latency period. On the contrary, for bothSulfobacillusspecies studied,S. thermosulfidooxidansandS. thermotolerans, were strongly impacted showing important lag phases before growth could take place. Additionally, the SX reagent showed disruption of cell walls and protein liberation during contact with all the different strains studied.