Recommended Guanidine Suppressor for the Next-Generation Caustic-Side Solvent Extraction Process

Moyer, Bruce A ; Delmau, Laetitia Helene ; Duncan, Nathan C ; Ensor, Dale ; Hill, Talon G ; Lee, Denise L ; Roach, Benjamin D ; Sloop Jr, Frederick {Fred} V ; Williams, Neil J

Oak Ridge National Laboratory

关键词: Solvent Extraction;    Cesium;    Nuclear Waste;   

DOI  :  10.2172/1060846
RP-ID  :  ORNL/TM-2012/625
RP-ID  :  DE-AC05-00OR22725
RP-ID  :  1060846

美国|英语

来源: UNT Digital Library

【 摘 要 】

The guanidine recommended for the Next-Generation Caustic-Side is N,N ,N -tris(3,7-dimethyloctyl)guanidine (TiDG). Systematic testing has shown that it is significantly more lipophilic than the previously recommended guanidine DCiTG, the active extractant in the commercial guanidine product LIX -79, while not otherwise changing the solvent performance. Previous testing indicated that the extent of partitioning of the DCiTG suppressor to the aqueous strip solution is significantly greater than expected, potentially leading to rapid depletion of the suppressor from the solvent and unwanted organic concentrations in process effluents. Five candidate guanidines were tested as potential replacements for DCiTG. The tests included batch extraction with simulated waste and flowsheet solutions, third-phase formation, emulsion formation, and partition ratios of the guanidine between the solvent and aqueous strip solution. Preliminary results of a thermal stability test of the TiDG solvent at one month duration indicated performance approximately equivalent to DCiTG. Two of the guanidines proved adequate in all respects, and the choice of TiDG was deemed slightly preferable vs the next best guanidine BiTABG.