The role of pe, pH, and carbonate on the solubility of UO{sub 2} and uraninite under nominally reducing conditions
- Polytechnic Univ. of Catalunya, Barcelona (Spain). Dept. of Chemical Engineering
- QuantiSci SL, Cerdanyola (Spain)
- Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Earth and Planetary Sciences
Experimental data obtained from uranium dioxide solubility studies as a function of pH and under nominally reducing conditions in a 0.008 mol/dm{sup 3} perchlorate medium and in a 1 mol/dm{sup 3} chloride solution are presented. The solubility of extensively characterized uraninite samples from Cigar Lake (Canada), Jachymov (Czech Republic), and Oklo (Gabon) was determined in a solution matching the composition of a groundwater associated with granitic terrain. The redox potential of the test solution was monitored throughout the experimental period. The results obtained were modeled using aqueous formation constants compiled by the NEA, using stability constants corrected to appropriate ionic strengths. A lower value of the solubility product of the uranium dioxide phase defined as fuel in the SKB uranium database provides reasonable solubilities for a wide span of experimental results at near to neutral pH. Differences in solubility between natural and synthetic samples are attributed to the presence of carbonate in the experiments performed with uraninites, while differences in solubility observed among the natural samples can be correlated to radiation effects at atomic scale.
- OSTI ID:
- 655489
- Journal Information:
- Geochimica et Cosmochimica Acta, Vol. 62, Issue 13; Other Information: PBD: Jul 1998
- Country of Publication:
- United States
- Language:
- English
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