Ultrasound enhances the recycling process and mechanism of lithium from spent LiFePO batteries by Acidithiobacillus ferrooxidans.

In this study, the ability of Acidithiobacillus ferrooxidans to oxidize Fe to Fe and recover battery black powder was investigated, establishing a system for leaching decommissioned lithium iron phosphate battery black powder from A. ferrooxidans. Black powder reduced the consumption of reagents and subsequent pressure for treating iron-bearing minerals using the iron source in waste LiFePO batteries. This study used ultrasonic waves to remove impurities on the surface and cracks in battery black powder, hindering the dissolution layer and enhancing the leaching effect through a cavitation reaction and microbial activation to promote the leaching process. A filter bag experiment was designed using the selective permeability of filter bags to investigate whether the leaching mechanism of A. ferrooxidans lithium iron phosphate is contact or non-contact. Under optimal leaching conditions, the lithium leaching rate reached 99.7%, and the leaching time was reduced from 7 to 5 days, achieving efficient leaching of lithium. The filter bag experiment concluded that A. ferrooxidans leaching of lithium iron phosphate was mainly a contact leaching mechanism.