Reversed Talspeak

Svantesson, I. 1984. A reversed TALSPEAK process for the separation of actinides from lanthanides. Thesis. Chalmers University of Technology, Goteborg. 

In the reverse TALSPEAK process, the An(III) + Ln(III) fraction is first coextracted from a feed, the acidity of which has to be reduced to 0.1 M by denitration or nitric acid extraction. An(III) are then selectively stripped using DTPA in citric acid (1 M) at pH 3 (hence the name reverse TALSPEAK process), and the Ln(III) are finally stripped by 6 M HN03. Attempts to apply this TALSPEAK variant to the treatment of actual UREX + raffinates are reported in the literature, but they involve several steps. The problematic Zr and Mo elements are first removed by direct extraction with HDEHP (0.8 M in di-iso-propylbenzene) from the high-acidity raffinate stream arising from the UREX + co-decontamination process (238). The remaining fission products and actinides can then be concentrated by acid evaporation and denitration processes. This concentrate is further diluted to a lower acidity (e.g., [HN03] = 0.03 M) to allow the coextraction of An(III) and Ln(III) by the TALSPEAK solvent. 

Collins, E.D., Benker, D.E., Bailey, P.D., Felker, L.K., Taylor, R.D., Delcul, G.D., Spencer, B.B., Bond, W.D., Campbell, D.O. 2005. Hot test evaluation of the reverse TALSPEAK process. Global 2005 Nuclear Energy System for Future Generation and Global Sustainability, October, Tsukuba, Japan. 

After the denitration, the process steps sequence of option 2 is similar to the "Reverse Talspeak Process" already developed on a cold laboratory scale at the KfK laboratories of Karlsruhe (19 for the recovery of actinides from HAW. It involves the coextraction of actinides with RE by HDEHP/TBP in n-dodecane at about pH2, the selective stripping of actinides by a Na5 DTPA-glycolic acid solution and the stripping of RE by 4 M HN03. In the case of option 2, the stripping of co-extracted... 

As far as the back-extraction of loaded HDEHP/TBP solvent is concerned (option 2), only simulated HAW solutions have been so far tested. Results reported elsewhere (10) indicated that Pu, Mo, Zr and U may be almost quantitatively removed from the loaded HDEHP/TBP solvent by an oxalate solution at pH 2.5 and confirmed that this organic mixture, employed according to the "Reverse Talspeak... 

In a modification of the TALSPEAK process known as the Reverse TALSPEAK process, trivalent actinides, and lanthanides together are extracted by 1 M HDEHP from the 0.1 M... 

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