Alkaline leaching of uranium from El-Sibaiya East Phosphorite in the presence of sodium peroxide

抄録

Chemical, mineralogical and radiometric investigation studies were executed on a representative phosphorite sample collected from El-Sibaiya East area to evaluate its suitability for the alkaline leaching of its uranium content. The uranium alkaline leaching was carried out in three phases using Na₂CO₃ and a mixture of Na₂CO₃/NaHCO₃ with/without an oxidant (Na₂O₂). Factors include; Na₂CO₃, NaHCO₃, Na₂O₂ concentrations; digestion temperature, reaction time and ore fineness were studied and optimized. The results pointed to that the best leaching efficiency of uranium (83.2%) was conducted using the mixture solution of Na₂CO₃/NaHCO₃ (0.5M) in the presence of 2.5% Na₂O₂ (w/w). The other conditions affected the leaching process were studied and optimized as 80 oC (leaching temperature), 3h (leaching time), 44μm (ore grain size) and a solid/liquid ratio of 2/25. The leached uranium was recovered by precipitation using NaOH solution where the precipitated product was defined by the XRD as sodium diuranate (Na₂U₂O₇) of high purity.