Abstract: In the process of leaching of uranium，Al³⁺ is found to form a complexation with fluorine,hence reduce the negative influence on uranium leaching. In order to better understand the influence of Al³⁺ on bacterial activity,bacteria growth cycle and oxidation rate of Fe²⁺ influenced by the concentration of Al³⁺ and the influence mechanism of the ion concentration on bacterial growth are investigated. The results show that: ①the activity of mixed bacteria is closely related to the concentration of Al³⁺. When the concentration of Al³⁺ is less than 8 g/L,the influence of Al³⁺ on oxidation capability and growth cycle of the mixed bacteria is very small; With the concentration increasing,its influence is getting more and more significant,and inhibition of mixed bacteria growth is more and more obvious.②When the concentration of Al³⁺ is less than 8 g/L,mixed bacteria show a stronger ability to regulate metabolism,namely by changing or adjusting the metabolic pathways to adapting to the new environment to some extent. Therefore,when usage of Al³⁺ is required for uranium bacteria leaching,its concentration should not exceed 8 g/L.

Key words: Al3+, Bioleaching of uranium, Mixed bacteria, Activity