caa a22 4500 378874152 CHVBK 20180305123416.0 cr unu---uuuuu 161128e20030801xx s 000 0 eng 10.1524/ract.91.8.463.20007 doi (NATIONALLICENCE)gruyter-10.1524/ract.91.8.463.20007 A kinetic model of the oxidative dissolution of brannerite, UTi2O6 [Elektronische Daten] [Bronwyn S. Thomas, Y. Zhang] The aqueous dissolution of synthetic brannerite (UTi2O6) in an open atmosphere has been investigated. Previous data in the literature have been combined with new experimental work, dealing with the release of uranium from brannerite as a function of solution pH and aqueous carbonate species, in oxygenated solutions. From these data we have developed a conceptual model for uranium release from brannerite consisting of two reaction steps: oxidation of surface uranium(IV) atoms, and subsequent detachment of U(VI) atoms into solution, which is catalysed by surface coordination with protons (acidic media) or carbonate species (alkaline media in equilibrium with the atmosphere). A kinetic rate law is derived for this simple reaction mechanism and fitted to experimental data. The resulting predictive equation for uranium release qualitatively describes the pH-dependent behaviour observed in experiment, and quantitatively gives an upper limit for uranium release from brannerite over a range of conditions and experiment types. © 2003 Oldenbourg Wissenschaftsverlag GmbH Laboratory techniques, experiments nationallicence Analytical chemistry nationallicence Inorganic chemistry nationallicence Thomas Bronwyn S. aut Zhang Y. aut Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 91/8/2003(2003-08-01), 463-472 0033-8230 91:8/2003<463 2003 91 ract https://doi.org/10.1524/ract.91.8.463.20007 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/ract.91.8.463.20007 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Thomas Bronwyn S. aut NATIONALLICENCE 700 1- Zhang Y. aut NATIONALLICENCE 773 0- Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 91/8/2003(2003-08-01), 463-472 0033-8230 91:8/2003<463 2003 91 ract CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter