Studies on parameters affecting uranium leaching from phosphate rock

Abstract

The effect of various chemical parameters such as NO3-, HCO3-, EDTA and citric acid on the uranium leaching from phosphate rock samples has been investigated by means of batch-type experiments and the total uranium concentration in the solution was analyzed by ICP-OES. EDTA has been found to leach uranium from phosphate rock at the highest rate, followed by carbonate and citrate. With the exception of nitrates, the ligand concentration (0.01 M and 0.001 M) appears to greatly enhance the leaching efficiency at the studied ligand concentrations. On other hand, the effect of pH differs significantly from one ligand to another, because EDTA is more effective in near neutral solutions (pH 6.5), whereas citrate in acidic solutions (pH 2.5).

Keywords

• Uranium leaching
• Phosphate rock
• Chemical parameters
• Batch-experiments
• Time-dependence