AUTHOR=Li Qian , Yang Yu , Ma Jinfang , Sun Jing , Li Guangyue , Zhang Ruiyong , Cui Zhao , Li Ting , Liu Xiaobei 

TITLE=Sulfur enhancement effects for uranium bioleaching in column reactors from a refractory uranium ore

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1107649

DOI=10.3389/fmicb.2023.1107649

ISSN=1664-302X

ABSTRACT=<p>The feasibility of sulfur enhancement for uranium bioleaching in column reactors was assessed with a designed mixed <italic>Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans</italic> and <italic>Leptospirillum ferriphilum</italic> from a refractory uranium ore. The uranium extraction reached 86.2% with the sulfur enhancement (1 g/kg) in 77 days leaching process, increased by 12.6% vs. the control without sulfur addition. The kinetic analysis showed that uranium bioleaching with sulfur enhancement in columns followed an internal diffusion through the product layer-controlled model. Ore residue characteristics indicated that sulfur enhancement could strengthen the porosity of passivation layer, improving the ore permeability. Notably, bacterial community analysis showed that sulfur enhancement at 1 g/kg could make the iron-oxidizing and sulfur-oxidizing bacteria on the ore surface maintain a good balance (approx. 1:1), and thus decomposing ore more effectively. Lastly, a possible mechanism model for uranium bioleaching with sulfur enhancement was proposed.</p>