Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits

Nature Communications
By: , and 

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Abstract

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U(VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U(IV) generated through biologically mediated U(VI) reduction is the predominant U(IV) species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (58-89%) of U is bound as U(IV)to C-containing organic functional groups or inorganic carbonate, while uraninite and U(VI) represent only minor components. The uranium deposit exhibited mostly 238U-enriched isotope signatures, consistent with largely biotic reduction of U(VI) to U(IV). This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U(IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits
Series title Nature Communications
DOI 10.1038/ncomms15538
Volume 8
Year Published 2017
Language English
Publisher Nature Publishing
Contributing office(s) National Research Program - Central Branch
Description Article: 15538: 8 p.