Spectroscopic and electrochemical studies of selected lanthanides and actinides in concentrated aqueous carbonate and carbonate-hydroxide solutions and in molten dimethyl sulfone

Technical Report · Fri Mar 01 04:00:00 EST 1985

DOI:https://doi.org/10.2172/5993632· OSTI ID:5993632

Varlashkin, P G

Electrochemical and spectroscopic studies of neptunium, plutonium, americium, californium, and terbium in concentrated aqueous carbonate and carbonate-hydroxide solutions have been carried out. Changes in the absorption spectra of Np(VII), Np(V), Pu(VI), Pu(V), Am(VI), and Am(V) in concentrated Na/sub 2/CO/sub 3/ solution and in the formal potentials of the Np(VI)/Np(V) and Pu(VI)/Pu(V) couples as a function of pH were observed. Heptavalent neptunium in concentrated Na/sub 2/CO/sub 3/ solution could only be producted at pH values close to or greater than 14. Plutonium(VII) in 2 M Na/sub 2/CO/sub 3/ solution could only be produced at hydroxide ion concentrations in excess of about 2.5 M. The complexation of Np(VII) and Pu(VII) in Na/sub 2/CO/sub 3/-NaOH solution seems to be mainly by hydroxide ions. Neptunium(IV) and plutonium(IV) are insoluble in Na/sub 2/CO/sub 3/ solution above ca. pH 11-12. Neptunium(III) in carbonate solution is rapidly oxidized by water to Np(IV). Plutonium(III) is insoluble in Na/sub 2/CO/sub 3/ solution. In K/sub 2/CO/sub 3/ solution Pu(III) is stable to oxidation by water but is very sensitive to air oxidation. The redox properties of Cf(III) in Na/sub 2/CO/sub 3/ and K/sub 2/CO/sub 3/ solutions at pH values from 8 to 14 were investigated. The oxidation of terbium(III) in K/sub 2/CO/sub 3/-KOH solution was studied. Spectroscopic and electrochemical studies of cerium, samarium, europium, ytterbium, uranium, neptunium, plutonium, and americium in molten dimethyl sulfone (DMSO/sub 2/) at 400 K were performed. Differences in the DMSO/sub 2/ solution absorption spectra of trivalent Sm, Eu, and Yb and divalent Eu compared with those in aqueous solution were observed. Complexation effects on the spectra of Ce(III), Ce(IV), U(VI), Np(VI), Pu(VI), and Am(VI) are more noticeable in poorly coordinating DMSO/sub 2/ than they are in water. 123 references, 54 figures, 11 tables.

• Research Organization: Tennessee Univ., Knoxville (USA)
• Sponsoring Organization: USDOE Office of Energy Research (ER)
• DOE Contract Number: AS05-76ER04447
• OSTI ID: 5993632
• Report Number(s): DOE/ER/04447-187; ON: DE85006381
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400400 -- Electrochemistry
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ABSORPTION SPECTRA
ACTINIDE COMPOUNDS
ALKALI METAL COMPOUNDS
AMERICIUM COMPOUNDS
AQUEOUS SOLUTIONS
CALIFORNIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATES
CERIUM COMPOUNDS
CHEMICAL REACTIONS
CHEMISTRY
COMPARATIVE EVALUATIONS
COMPLEXOMETRY
DATA
DISPERSIONS
ELECTROCHEMISTRY
EUROPIUM COMPOUNDS
EXPERIMENTAL DATA
HIGH TEMPERATURE
HYDROGEN COMPOUNDS
HYDROXIDES
INFORMATION
MIXTURES
NEPTUNIUM COMPOUNDS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDATION
OXYGEN COMPOUNDS
PH VALUE
PLUTONIUM COMPOUNDS
POTASSIUM CARBONATES
POTASSIUM COMPOUNDS
RAMAN SPECTRA
RARE EARTH COMPOUNDS
REDOX REACTIONS
SAMARIUM COMPOUNDS
SODIUM CARBONATES
SODIUM COMPOUNDS
SODIUM HYDROXIDES
SOLUBILITY
SOLUTIONS
SPECTRA
SULFONES
TERBIUM COMPOUNDS
TRANSPLUTONIUM COMPOUNDS
TRANSURANIUM COMPOUNDS
URANIUM COMPOUNDS
YTTERBIUM COMPOUNDS