Removal of Plutonium from Contaminated Soil by Chemical Leaching

Due to the high cost and technical challenges for the treatment and disposal of heavy plutonium(Pu) contaminated soils, it is deserved to develop efficient methods to remove Pu from contaminated soil in order to reduce its concentration and the volume of the radioactive waste required to be deposed with high standard. Inorganic acids, organic acids and oxidants were screened deliberately for removal Pu from one kind of Pu contaminated desert soil. The leaching process was investigated for the dependence of the decontamination efficiency with batch wise leaching. Furthermore, the decontamination efficiencies of Pu from the leachate were studied by flocculation deposition. The removal efficiencies increased with the augment of liquid-solid ratio, temperature, stirring time and the maximum Pu removal efficiency of 90% specific activity was gained by sulfuric acid. The inorganic and organic flocculants are capable to remove Pu in the leachate completely with decontamination factor more than 5×103, and the weight of final residue less than 10% of the initial contaminated soil and the remaining specific activity of Pu-239 in the treated leachate less than 0.07Bq/L, which fulfills the requirement for direct discharge.