title: Kinetic study of uranium residue dissolution in ammonium carbonate media.
abstract: The purpose of this study was to determine the kinetics of the dissolution of a uranium residue in ammonium carbonate media. The residue is generated in the production of medical isotopes. The effects of parameters, such as varying peroxide and carbonate concentrations, dissolution time as well as temperature on the extraction rate have been separately studied. Results indicate complete dissolution of the residue at 60 °C, after 30 min, in ammonium carbonate solution enriched with hydrogen peroxide. The yield and rate of uranium extraction were found to increase as a function of both temperature, in the range of 25-60 °C, and hydrogen peroxide concentration. The extraction process was governed by chemical reaction as the activation energy was found to be 45.5 kJ/mol. The order of reaction with respect to uranium concentration was found to be approximately first order.
authors.affiliation: Department of Materials Science & Metallurgical Engineering, University of Pretoria, Lynnwood Road, Pretoria, 0002 South Africa.
authors.forename: B
authors.initials: B
authors.lastname: Kweto
authors.affiliation: Department of Materials Science & Metallurgical Engineering, University of Pretoria, Lynnwood Road, Pretoria, 0002 South Africa.
authors.forename: D R
authors.initials: DR
authors.lastname: Groot
authors.affiliation: Applied Chemistry, South African Nuclear Energy Corporation (Necsa), Pelindaba, Pretoria, South Africa.
authors.forename: E
authors.initials: E
authors.lastname: Stassen
authors.affiliation: Applied Chemistry, South African Nuclear Energy Corporation (Necsa), Pelindaba, Pretoria, South Africa.
authors.forename: J
authors.initials: J
authors.lastname: Suthiram
authors.affiliation: Department of Science and Technology, Preclinical Drug Development Platform, North West University, Potchefstroom, South Africa.
authors.forename: J R
authors.initials: JR
authors.lastname: Zeevaart
keywords: Activation energy and uranium residue; Ammonium carbonate; Chemical reaction; Extraction rate; Hydrogen peroxide; Leaching