Bibliographic Citation
| Document | For copies of Journal Articles, please contact the Publisher or your local public or university library and refer to the information in the Resource Relation field. For copies of other documents, please see the Availability, Publisher, Research Organization, Resource Relation and/or Author (affiliation information) fields and/or Document Availability. |
|---|---|
| Title | Alteration of Coffinite (USiO{sub 4}) Under Reducing and Oxidizing Conditions |
| Creator/Author | Deditius, Artur Piotr ; Utsunomiya, Satoshi ; Ewing, Rodney C. [Geological Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI, 48109 (United States)] |
| Publication Date | 2007 Jul 01 |
| OSTI Identifier | OSTI ID: 21062380 |
| Other Number(s) | Other: ISBN 978-1-55899-942-8; TRN: US08V1546077199 |
| Resource Type | Conference |
| Resource Relation | Conference: Symposium on Scientific Basis for Nuclear Waste Management, Boston - Massachusetts (United States), 27 Nov - 1 Dec 2006; Other Information: Country of input: France; 17 refs; Related Information: In: Proceedings of the symposium on Scientific Basis for Nuclear Waste Management XXX, by Dunn, Darrell [ed. Southwest Research Inst., San Antonio, Texas (United States)]; Poinssot, Christophe [ed. CEA-Saclay, 91191 Gif-sur-Yvette cedex (France)]; Begg, Bruce [ed. Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)], v. 985, 663 pages. |
| Research Org | Materials Research Society, 506 Keystone Drive, Warrendale, PA, 15086-7573 (United States) |
| Subject | 12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; COFFINITE; ELECTRON MICROPROBE ANALYSIS; ORGANIC ACIDS; OXIDATION; REDUCTION; URANIUM DIOXIDE; URANIUM IONS; URANIUM SILICATES |
| Description/Abstract | Samples of natural coffinite (USiO{sub 4}.nH{sub 2}O) 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{sub 2})(SiO{sub 3}OH)(H{sub 2}O){sub 1.5}] and jachymovite [(UO{sub 2})(SO{sub 4})(OH){sub 14}(H{sub 2}O){sub 13}] precipitated with no rare earth elements. Based on the charge balance calculation, we suggest that the amount of U{sup 6+} in the coffinite is less than 0.2 [apfu] and U{sup 6+} is accommodated in the structure via substitution: U{sup 4+} + Si{sup 4+} {r_reversible} U{sup 6+} + 2(OH){sup -}. The high and variable totals for electron microprobe analyses indicate that H{sub 2}O 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. (authors) |
| Publisher | Materials Research Society - MRS, Warrendale (United States) |
| Country of Publication | United States |
| Language | English |
| Format | Medium: X; Size: page(s) 47-52 |
| System Entry Date | 2008 Aug 25 |
Top | |