Preferential and efficient extraction of lithium under the combined action of reduction of herb-medicine residue and leaching of oxalic acid

With the increasing demand for lithium resources, the efficient recovery of lithium from spent lithium-ion batteries (LIBs) has become the focus of social attention. Herein, a combined process of reduction roasting of herb-medicine residue (HMR) and oxalic acid (OA) leaching is proposed to improve the recovery efficiency of lithium. Due to the large amount of reducing gas produced by the pyrolysis of herb-medicine residue, the layered structure of LiNixCoyMnzO2 cathode powder can be destroyed at 650celcius for 10 min, and the cathode powder is converted into Li2CO3, Ni, Co, MnO. Moreover, about 99.6 % of Li in the roasting residue can be selectively extracted by 0.5 mol L-1 oxalic acid for 20 min. Under the combined action of HMR and OA, the extraction efficiency and kinetics of lithium are improved simultaneously. This work achieves synergistic treatment of two types of waste from the perspective of waste management for waste. Meanwhile, it provides an alternative and innovative approach for the difficult problem of low efficiency of lithium recovery from spent LIBs.

Automated summary

This study proposes a combined process of reduction roasting of herb-medicine residue and oxalic acid leaching to improve the recovery efficiency of lithium from spent lithium-ion batteries. By utilizing the reducing gas produced from the pyrolysis of herb-medicine residue, the layered structure of the cathode powder is destroyed and converted into Li2CO3, Ni, Co, and MnO. Additionally, selective extraction of lithium is achieved using oxalic acid, and the efficiency and kinetics of lithium extraction are improved under the combined action of herb-medicine residue and oxalic acid.