Solubility data for U(VI) hydroxide and Np(IV) hydrous oxide: application of MCC-3 methodology
Experiments based on a modified MCC-3S test method were conducted to investigate the solubility of U(VI) hydroxide (the mineral schoepite) and Np(IV) hydrous oxide at ambient temperature. The solubility of U(VI) hydroxide was investigated in carbonate-free, oxidizing aqueous solutions in the pH range of 3 to 11. The measured concentrations of dissolved U confirm the amphoteric behavior of U(VI) hydroxide solid and the importance of anionic U(VI) hydroxyl complexes in accurately calculating the solubilities of U(VI) solids under basic pH conditions. the effect of fluoride complexation on the solubility of Np(IV) hydrous oxide was studied in carbonate-free, near-neutral to alkaline solutions that contained 100 ppM total F. For solutions in which sodium dithionite (Na/sub 2/S/sub 2/O/sub 4/) and metallic Fe were used as reducing agents, the addition of 100 ppM F had no measurable effect on the solubility of Np(IV) hydrous oxide.
- Research Organization:
- Pacific Northwest Labs., Richland, WA (USA)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 6061763
- Report Number(s):
- PNL-SA-12324; CONF-841157-82; ON: DE85007765
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ACTINIDE COMPOUNDS
CHALCOGENIDES
HYDROGEN COMPOUNDS
HYDROXIDES
NEPTUNIUM COMPOUNDS
NEPTUNIUM OXIDES
OXIDES
OXYGEN COMPOUNDS
PH VALUE
SOLUBILITY
TRANSURANIUM COMPOUNDS
URANIUM COMPOUNDS
URANIUM HYDROXIDES
URANYL COMPOUNDS