Thermogravimetric study of the reaction of uranium oxides with fluorine

Motohiro Komura, Nobuaki Sato, Akira Kirishima, Osamu Tochiyama

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Thermogravimetric study of the reaction of uranium oxides with fluorine was conducted by TG-DTA method using anti-corrosion type differential thermobalance. When UO2 was heated from R.T. to 500 °C in 5% F2/He atmosphere, the weight increase appeared at ca. 250 °C with an exothermic peak. Then the weight decreased slightly with a small exothermic peak followed by the complete volatilization with a large exothermic peak at ca. 350 °C. At a flow rate of 15, 30, 60 ml min-1, there seemed to be no significant change for the fluorination of UO2. With the different heating rates of 1, 2, 5 and 10 °C min-1, the fluorination peak shifted to higher temperature with increasing heating rates. For the comparison with thermogravimetric results, phase analysis by XRD method was conducted for the products obtained at different temperatures. At 260 °C, the product was UO2 with a small amount of the intermediate compound, UO2F. The amount of this compound increased with increasing temperature up to 320 °C. Then another phase of UO2F2 appeared at 340 °C but it was immediately fluorinated to the volatile fluoride. When U3O8 was used as a starting material, it was found that the steep weight decrease peak appeared at ca. 350 °C and the uranium volatilized completely. This result suggests that fluorination of U3O8 occurs at this temperature forming UF6. Uranium trioxide showed the similar fluorination behavior to that of U3O8.

Original languageEnglish
Pages (from-to)673-675
Number of pages3
JournalJournal of Alloys and Compounds
Volume451
Issue number1-2
DOIs
Publication statusPublished - 2008 Feb 28

Keywords

  • Fluoride
  • Fluorine
  • Oxide
  • Thermogravimetry
  • Uranium

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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