Alteration of coffinite (USiO4) under reducing and oxidizing conditions

Artur Piotr Deditius, Satoshi Utsunomiya, Rodney C. Ewing

研究成果: 書籍/レポート タイプへの寄稿会議への寄与

3 被引用数 (Scopus)

抄録

Samples of natural coffinite (USiO4·nH2O) from Grants uranium region, New Mexico were investigated in order to understand the alteration process of coffinite under reducing and oxidizing conditions. Alteration of the primary coffinite under reducing conditions was promoted by organic acids, and as a result, secondary coffinite precipitated. Subsequently oxidizing fluids altered the coffinite, and (Na,K)-boltwoodite [(Na,K)(UO 2)(SiO3OH)(H2O)1.5] and Jáchymovi te [(UO2)(SO4)(OH)14(H 2O)13] precipitated with no rare earth elements. Based on the charge balance calculation, we suggest that the amount of U6+ in the coffinite is less than 0.2 [apfu] and U6+ is accommodated in the structure via substitution: U4+ + Si4+ ≅ U 6+ + 2(OH)-. The high and variable totals for electron microprobe analyses indicate that H2O is not an essential component in coffinite structure. The U-Pb ages of coffinite formation vary from 36.6-0 Ma suggesting that the coffinite has precipitated continuously in this period and organic matter can preserve reducing conditions even when oxidizing conditions dominate.

本文言語英語
ホスト出版物のタイトルScientific Basis for Nuclear Waste Management XXX
ページ47-52
ページ数6
出版ステータス出版済み - 12月 1 2007
外部発表はい
イベント2006 MRS Fall Meeting - Boston, MA, 米国
継続期間: 11月 27 200612月 1 2006

出版物シリーズ

名前Materials Research Society Symposium Proceedings
985
ISSN(印刷版)0272-9172

その他

その他2006 MRS Fall Meeting
国/地域米国
CityBoston, MA
Period11/27/0612/1/06

!!!All Science Journal Classification (ASJC) codes

  • 材料科学(全般)
  • 凝縮系物理学
  • 材料力学
  • 機械工学

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