Actinide stripping by a hydrophilic BTP ligand in aqueous HNO 3 from TODGA containing organic phase.

Transcription

1 First SACSESS International Workshop: Towards safe and optimised separation processes, a challenge for nuclear scientists Warsaw Actinide stripping by a hydrophilic BTP ligand in aqueous HNO 3 from TODGA containing organic phase. L. Steczek, J. Narbutt, M. Rejnis,P. Moisy 2, M. Ch. Charbonnel 2 Institute of Nuclear Chemistry and Technology, 2 Alternative Energies and Atomic Energy Commission

2 Bibliography Aromatic poly N dentate ligands Affinity to protonate nitrogen atoms decreases in the order: The simplest aromatic poly-n-dentate ligand is 2,2'-bipyridil > > PAGE 2

3 The Choice of Selected ligand Lipophilic poly-n-nitrogen ligands are broadly studied as selective extractants for separation of long-lived actinides from irradiated nuclear fuel. In the last years, the research was focused on the derivatives of bis-triazinyl pyridine (BTP) which selectively extract actinides(iii) from lanthanides(iii) from aqueous HNO 3 solutions to organic solvents. Moreover, selective stripping of minor actinides can be done also, using a hydrophilic ligand, e.g. SO 3 -Ph-BTP delivered by Technocomm Ltd (UK). HO 3 S HO 3 S N N N N N N N SO 3 H SO 3 H HSO 3 PhBTP PAGE 3

4 Bibliography Complexes of An(III), Ln(III) β Cm Eu β 5,4 5,2 β 2 9,3 8 β 3 2,2,2 with HSO 3 PhBTP Stability constant of An with SO 3 Ph BTP ligand TRLFS, An 3+ forms more stable complexes than Ln 3+. Complexes (:), (:2) and (:3) were observed Stability constants of Cm and Eu with SO 3 Ph BTP ligand; at ph 3 (TRLFS) Ch.M. Ruff, U. Müllich, A. Geist, P. J. Panak, Dalton Trans., 22, 4, 4594 D Am HSO 3 PhBTP mol L - Distribution ratio of Am (.5 M NH 4 NO 3 + HNO 3 (ph )/.2 M TODGA in kerosene A. Geist et al., Solv. Extr. Ion Exch., 3: , 22 PAGE 4

5 Liquid liquid Extraction of Actinides with TODGA In certain separation schemes under study (innovative-sanex) the f-block elements are extracted together from acidic PUREX raffinate to the organic phase using e.g. lipophlilic tri-o-dentate ligand, TODGA. log D Th(IV) Pu(IV) UO2(VI) log [HNO3].2 M TODGA TODGA Yuji Sasakia*, Yasuhiro Tsubataa, Yoshihiro Kitatsujia, Yumi, Solvent Extraction and Ion Exchange Volume 3, Issue 4, PAGE 5

6 Principle of the LLE Method An 4+ + stodga + uno 3- = [An(TODGA) s (NO 3 ) u ] 4-u An 4+ + uno 3- = [An(NO 3 ) u ] 4-u An 4+ + kbtp = [An(hsBTP) k ] 4-4k hsbtp 4- + ah + = [hsbtp(h + ) a ] 4-a where hsbtp = SO 3 PhBTP D = [ An [ An] TODGA u l ( NO [ An( NO 3 ) u ] 4 u 3 ) u ] K ex = An TODGA s ( NO3 ) u s An TODGA NO u 3 D= + D u k u Knitrate, u[ NO3 ] + i i K BTPk hsbtp k D = β 2... n L D L +β L 2 + β n PAGE 6

7 Method of the determination of the Distribution coefficient spectrophotometry spectrophotometry Complex Arsenazo(III)-Th 66 nm Complex Arsenazo(III)-UO2(2+) 655 nm alpha spectrometry gamma spectrometry c/s MeV c/s kev PAGE 7

8 Purification of ligand Ligand has to be additional purify in case of the presence sulphate which form relatively strong complexes with An(IV) SO3H Ph BTP contaminated SO43 SO3 Ph BTP purified Test with BaCl 2 can generate large amount of white powder Neutralization wiht NaOH until ph = 7 D Solubilization in MeOH at least three times HSO 3 PhBTP mol L Evaporation or precipitation with acetone Müllich, Udo, Geist, Andreas, Zevaco, Thomas EP A PAGE 8

9 Preliminary experiments Experiments with Th(IV), Pu(IV) UO 2+ 2,PuO 2+ 2, NpO 2+ 2 reduction At ph we observed the formation of the complex with Pu(VI) and reduction Optical density.4.3 Pu(VI) Pu(VI)L.2 Instability of. The complex time 3 min nm. M Pu(VI), HSO 3 PhBTP -.5 M, ph PAGE 9

10 Extraction of An as a function of ligand log D/D- 3,5 3 2,5 2,5,5 Am(III) Th(IV) U(VI) ,5 log HSO3PhBTP Extraction of Th(IV), Am(III) and UO 2 2+ by TODGA in 5% octanol-keresone from acidic aqueous solution. Temperature of extraction 25 ºC, time 3 min, O/A = UO 2 2+ Th Am C An mol/l.2. trace C NO - 3 Phase aqueous Phase organic.5 M.6 M TODGA.5 M HNO 3.6 M TODGA.5 M HNO 3. M TODGA PAGE

11 Results Extraction of Americium from acidic solution HSO 3 PhBTP and NaNO 3 log(d/d-) M HNO3.5 M HNO3. M HNO3.5M HNO3 with Pu M HNO3 avec Pu k= k= log (HSO 3 PhBTP) Phase organic:. M TODGA and.6 M TODGA when Am was measured with Pu acidity log β log β ± ± ± ± ± ± ± ± In progress In progress β Cm Eu β 5,4 5,2 β 2 9,3 8 β 3 2,2,2 A. Geist, U. Mullich, G. Modolo, A. Wilden ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN , OECD 22 (-9) PAGE

12 Results Extraction of Plutonium from acidic solution HSO 3 PhBTP and NaNO 3 D/D M HNO3 France M HNO3 k= k= log(hso 3 PhBTP) acidity log β log β ± (.5) ± (.5) 8.98 ± (.) 8.8 ± (.2) 3. In progress In progress C Pu(VI) =. mm,. M (H, Na)NO 3 TODGA =.6 M in kerosene/5% octanol PAGE 2

13 Results Extraction of Uranium(VI) and Thorium(IV) from acidic solution HSO 3 PhBTP and NaNO 3 UO2(2+) Th(IV) log D/D-,9,8,7,6,5,4,3,2, UO2(2+) k= tgα= -2,5-2 -,5 - -,5 log HSO3PhBTP log D/D-,8,6,4,2,8,6,4,2 Th(IV) k=2-2,5-2 -,5 - -,5 log HSO3PhBTP log K = M HNO 3 TODGA.6 M preliminary results log K = 3.63 log K 2 = 6,.5 M HNO 3 TODGA.6 M PAGE 3

14 Conclusion Am 3+,Th 4+, Pu 4+ forms complexes :, :2 and UO 2+ 2, : under the conditions of experiments. No evidence of the complexes :3 under the conditions of experiments. The results for Am 3+ are in accordance with the data existed for Cm(III) and Eu(III). The order of the conditional stability constants for the complexes : is Pu 4+ ~ Am 3+ > Th 4+ > UO PAGE 4

15 ACKNOWLEDGEMENTS LN Dr. Philippe Moisy Dr. M. Ch. Charbonnel L. Berthon C. Berthon N. Boubals T. Dumas D. Guillaumont P. Guilbaud C. Tamain L. Guerin N. Zorz S. Petit R. Burgaud I. Dantille S. Mostapha O.Pecheur M. Audras M. Autillo L8 M. Guigue J. Vermeulen J. Maurin M. Rejnis K. Lyczko Prof J. Narbutt Prof. G. Zakrzewska Kołtuniewicz A. Miśkiewicz M. Buta D. Gajda A. Abramowska W. Olszewska P. Nieściór K. Kiegiel PAGE 5