Uranium release from a natural rock under near-natural oxidizing conditions

Understanding the behavior of uranium in environmental contexts is crucial for developing effective remediation strategies. This study investigates the release and transport of uranium from a uraninite-containing rock under various conditions that simulate natural waters, a topic that remains poorly understood. The objective was to characterize uranium dissolution in deionised, tap, and mineral waters, while also comparing results with experiments using 0.1M Na2CO3 and 0.1M H2SO4. Batch experiments were performed without shaking to accurately assess uranium release dynamics. The findings reveal that the addition of carbonate significantly enhances uranium solubilization, whereas the presence of pyrite retards the initial release of uranium. Additionally, it was found that silica and other constituents of the rock can further hinder uranium transport. These results provide valuable insights into the geochemical processes influencing uranium mobility in the subsurface environment, with implications for the management of contaminated sites, particularly those associated with mining activities.