Abstract
The behavior of uranium in environments, ranging from those of natural systems responsible for the formation of uranium deposits to those of nuclear reactors providing 11% of the world's electricity, is governed by processes involving high-temperature aqueous solutions. It has been well documented that uranium is mobile in aqueous solutions in its oxidized, U6+ state, whereas in its reduced, U4+ state, uranium has been assumed to be immobile. Here, we present experimental evidence from high temperature (>100 °C) acidic brines that invalidates this assumption. Our experiments have identified a new uranium chloride species (UCl4°) that is more stable under reducing than oxidized conditions. These results indicate that uranium is mobile under reducing conditions and necessitate a re-evaluation of the mobility of uranium, particularly in ore deposit models involving this metal. Regardless of the scenario considered, reducing conditions can no longer be considered a guarantee of uranium immobility.
| Original language | English |
|---|---|
| Article number | 1469 |
| Journal | Nature Communications |
| Volume | 9 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 1 2018 |
| Externally published | Yes |
Funding
Funding for A.T.’s visit to the Los Alamos National Laboratory (LANL) was provided by a Seaborg Institute Summer Research Fellowship and is gratefully acknowledged. Additional support for A.T.’s stay at LANL was supplied by Natural Sciences and Engineering Research Council of Canada Alexander Graham Bell and Michael Smith Foreign Study Supplement Canada Graduate Scholarships. Research presented in this article was supported by the Laboratory Directed Research and Development program of Los Alamos National Laboratory under project number 20180007DR.