RECOVERY OF TRIVALENT LANTHANIDES AND ACTINIDES BY TBP-EXTRACTION FROM HIGHLY-CONCENTRATED NITRATE SOLUTIONS

摘要

The distributions of trivalent lanthanides, Am and Cm were experimentally studied in the bi-phase extraction system of TBP-dodecane and molten Ca(NO{sub}3){sub}2·xH{sub}2O (hydrate melt) having different water content. The influence of the water content in the hydrate melt was studied, and it was shown that even a small increase of water content significantly influences the extraction of trivalent elements. The influence of the temperature was studied, and it was shown that lower temperature is favorable for their recovery. The characteristics of the TBP extraction using hydrate melt of Ca(NO{sub}3){sub}2 were compared with TBP extraction system using concentrated nitric acid as an inorganic phase. Based on the experimental results, feasibility and condition of the extraction recovery of trivalent lanthanides and actinides by TBP from hydrate melt of Ca(NO{sub}3){sub}2 were discussed.