Uranium dissolution in hyperalkaline TMA-OH solutions: Preliminary results

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Abstract

Leaching experiments were performed with depleted UO2 powders in tetramethylammonium solutions (TMA-OH) at pH 13.5 and 12.5, and at different UO2 surface area to volume of solution (SA/V) ratio's to determine the solubility and the dissolution kinetics of UO2 at high pH in absence of cations dominating cementitious waters (Ca, Na, K). The solubility of UO2 increased from pH 12.5 to 13.5 and by increasing the SA/V ratio up to 100 m-1. However, no known U secondary-phases were predicted by geochemical calculations to control the measured U-concentrations. A two-stop dissolution process was put forward: 1- a fast initial rate, surface controlled and hydroxo promoted and 2- a sorption process at low SA/V ratio or a continuous residual dissolution process at high SA/V ratio.

Details

Original languageEnglish
Title of host publicationATALANTE 2016 INTERNATIONAL CONFERENCE ON NUCLEAR CHEMISTRY FOR SUSTAINABLE FUEL CYCLES
Subtitle of host publication5th International ATALANTE International Conference on Nuclear Chemistry for Sustainable Fuel Cycles
Pages306-313
Volume21
DOIs
Publication statusPublished - 1 Dec 2016
EventATALANTE 2016 - 5th International Conference on Nuclear Chemistry for Sustainable Fuel Cycles - Montpellier, France
Duration: 5 Jun 201610 Aug 2016

Publication series

NameProcedia Chemistry
PublisherElsevier
ISSN (Print)1876-6196

Conference

ConferenceATALANTE 2016 - 5th International Conference on Nuclear Chemistry for Sustainable Fuel Cycles
Abbreviated titleATALANTE 2016
CountryFrance
CityMontpellier
Period2016-06-052016-08-10

Keywords

  • uranium dioxide, dissolution, alkaline, pH, TMA-OH

ID: 6771376