Title : Kinetics Leaching Study of Uranium from Algerian Phosphate by Sulfuric Acid
Authors : S. Chegrouche1, A. Mellah2, D. Nibou3, B. Bensmain4, M.Barkat5, A. Aknoun6
About The Authors
1,5,6 Nuclear Research Center of Draria, Atomic Energy Commission, BP 43, 16050 Draria, Algiers, Algeria.
2 Nuclear Research Center of Algiers, Atomic Energy Commission, BP 399, 16000 Algiers, Algeria.
3,4Laboratory of Materials Technology, University of Science and Technology Houari Boumediene, BP 32, 16123,
El-Alia, Bab-Ezzouar, Algiers, Algeria.
The kinetics of dissolution of an Algerian phosphate in sulfuric acid has been investigated in the presence of hydrogen peroxide (H2O2) as oxidant. The effect of different parameters such as leaching time, sulfuric acid concentration, reaction temperature have been studied in order to optimize various process parameters for maximizing the recovery of uranium. Uranium optimal dissolution efficiency of 87 % was obtained under the following conditions: after 2 h contact time, leaching using 1.5 M sulfuric acid at 50 °C and 1.5 M H2O2. A mathematical model in the following form, including the effects of parameters was established to express the dissolution kinetics of phosphate ore: 1-(1-X)1/3 and 1-(2/3)X-(1-X)2/3 . The activation energy for the process was found to be 12 KJ/mol. This low activation energy supported the findings that the Algerian phosphate leaching rate is controlled by diffusion process.