Oxidation of Pu(III) by nitric acid in tri-n-butyl phosphate solutions. Part I. Kinetics of the reaction and its effect on plutonium losses in countercurrent liquid-liquid extraction
Oxidation of Pu(III) in tri-n-butyl phosphate solutions containing nitric acid has been studied by ultraviolet/visible spectrophotometry. The concentrations of Pu(IV) and nitrous acid (HNO/sub 2/), one of the reaction intermediates/products, were monitored. An autocatalytic reaction mechanism is proposed in which a small amount of HNO/sub 2/ is generated during an induction period. It then catalyzes the reaction by reacting with nitric acid to produce NO/sub 2/, which oxidizes Pu(III) in the rate-determining step. It is suggested a nitritoplutonium(IV) complex is formed that finally reacts with nitric acid to form more HNO/sub 2/. Reaction rates, measured under conditions similar to those encountered in a solvent extraction contactor, indicate that the reaction proceeds rapidly at concentrations of HNO/sub 3/ greater than about 0.2 M in the organic solutions, and it is responsible for plutonium losses often observed in solvent extraction operations.
- Research Organization:
- Atomic Energy of Canada Limited Whiteshell Nuclear Research Establishment Pinawa, Manitoba, ROE ILO
- OSTI ID:
- 7178643
- Journal Information:
- Nucl. Technol.; (United States), Journal Name: Nucl. Technol.; (United States) Vol. 56:3; ISSN NUTYB
- Country of Publication:
- United States
- Language:
- English
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ACTINIDE COMPLEXES
ACTINIDES
BUTYL PHOSPHATES
CATALYSIS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPLEXES
DISPERSIONS
ELEMENTS
ESTERS
EXTRACTION
FUEL CYCLE
HYDROGEN COMPOUNDS
INORGANIC ACIDS
KINETICS
LOSSES
METALS
MIXTURES
NITRIC ACID
NITRITES
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
NITROUS ACID
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANIC SOLVENTS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHOSPHORIC ACID ESTERS
PLUTONIUM
PLUTONIUM COMPLEXES
PLUTONIUM RECYCLE
PROCESS SOLUTIONS
REACTION INTERMEDIATES
REACTION KINETICS
SEPARATION PROCESSES
SOLUTIONS
SOLVENT EXTRACTION
SOLVENTS
SPECTRA
SPECTROPHOTOMETRY
TBP
TRANSURANIUM COMPLEXES
TRANSURANIUM ELEMENTS
ULTRAVIOLET SPECTRA
VISIBLE SPECTRA