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Pyrosulfate fusion vs. TEVA / TRU forcing the issue

Pyrosulfate fusion vs. TEVA / TRU forcing the issue. Shane Knockemus U.S. EPA / NAREL Montgomery, AL November 11, 2002. Advantages of fusion Achieves total sample dissolution (including refractory material) of nearly any type of sample. Rapid and vigorous. Not many reagents consumed.

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Pyrosulfate fusion vs. TEVA / TRU forcing the issue

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  1. Pyrosulfate fusion vs. TEVA / TRUforcing the issue Shane Knockemus U.S. EPA / NAREL Montgomery, AL November 11, 2002

  2. Advantages of fusion Achieves total sample dissolution (including refractory material) of nearly any type of sample. Rapid and vigorous. Not many reagents consumed. Insures homogeneity between tracer and sample. Disadvantage of fusion Introduces large amount of sulfate ions into sample matrix, which may effect some separation processes. Advantages / disadvantage / goal Goal: To achieve a reliable separation process for Am, Pu, Th, and U when analyzing a sample put into solution by pyrosulfate fusion.

  3. Potassium fluoride / pyrosulfate fusion • 0.5-1.0 gram soil in Pt dish • 1 g KF, 1.3 g KHF2…….FUSE • 3 mL 18 M H2SO4, 2 g Na2SO4…….FUSE

  4. TEVA / TRU Separation Scheme

  5. Experiment 1 flowchart cake HNO3 / Al(NO3)3 TEVA / TRU

  6. Poor Pu / Th separation (exp.1)

  7. Experiment 1 Results

  8. Experiment 2 flowchart cake 16 M HNO3 HNO3 / Al(NO3)3 TEVA / TRU

  9. Pu spectrum with Th contamination (exp. 2)

  10. Experiment 2 Results

  11. Influence of Matrix Constituents on TEVA Find a way to eliminate the SO4-2 introduced during the fusion before the sample is loaded onto TEVA / TRU.

  12. Experiment 3 flowchart cake TEVA / TRU HCl Calcium phosphate pptn HNO3 / Al(NO3)3

  13. Am and U spectra (exp. 3)

  14. Experiment 3 Results

  15. Experiment 4 flowchart cake TEVA / TRU HCl BaSO4 pptn HNO3 / Al(NO3)3 Titanous hydroxide pptn K+EDTA

  16. Th spectra (exp. 4)

  17. Clean Pu spectrum (exp. 4)

  18. Experiment 4 Results **Uranium recovery was 0% because there was no valence adjustment prior to BaSO4 coprecipitation

  19. Experiment 5 • This experiment was carried out the same as experiment 4, but instead of a titanous hydroxide precipitation, a calcium phosphate precipitation was used. • Prior to the BaSO4 precipitation U+6 was reduced to U+4 with hydrazine and TiCl3

  20. Spectra experiment 5

  21. Experiment 5 Results

  22. Experiment 6 flowchart cake HCl / HF TEVA / TRU diphonix destroy resin HNO3 / Al(NO3)3

  23. Usefulness of diphonix • Diphonix will help separate the sample from certain matrix constituents introduced to the sample as part of the digestion process. • Sample loaded in 1 M HCl / 0.5 M HF. Actinides stick, while troublesome ions not be sorbed by the resin.

  24. Loading of sample on diphonix • 0.3 g of diphonix resin packed into column • Resin charged with 5 mL 1 M HCl • Cake dissolved in 30 mL 1 M HCl / 0.5 M HF • Sample loaded onto column • Column rinsed with 5 mL 1 M HCl • Resin destroyed by charring with H2SO4 and HNO3, followed by oxidation of organics with HClO4

  25. Spectra of experiment 6

  26. Experiment 6 Results

  27. Evaluation of data for exp. 6 MAPEP did not have certified values for Th nuclides

  28. Final tally of experiments (hit or miss)

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