Total Component Recovery of Spent LiFePO4 Cathode Powder: A Leaching-Adsorption Process

In recent years, the large consumption of lithium-ion batteries (LiBs) has caused resource waste and environmental pollution. It is crucial to recycle and reuse LiBs, especially the valuable elements from the spent LiBs. In this research, a new, sustainable, and easy-to-implement process for the recycling of spent LiFePO4 cathode powder is proposed. 732 cation exchange resin is used as a leaching agent and an adsorbent to leach and adsorb Li and Fe from the spent LiFePO4 powder. The effects of various parameters, such as the cathode scrap-to-resin ratio (1/9), time (35 min), water addition (30 mL), and reaction temperature (30 °C), on the resin leaching and adsorption of the waste LiFePO4 cathode powder have been investigated. The effect of acid concentration on the elution rate during resin elution and experiments on the recyclability of the resin has been carried out as well. The results indicate that it is technically and economically feasible and environmentally friendly to use the 732 cation exchange resin to recover the waste LiFePO4 cathode powder. Products including high-purity Li2CO3 (99.95%), Fe2O3, and high-purity phosphoric acid can be obtained based on this process, through which a full component recovery with a high recovery rate was achieved. We investigated the reaction of kinetic analysis and also explored the effect of reaction conditions on the reaction. In contrast to previous studies on spent LiFePO4 cathode powder, our approach is promising and is analyzed as follows: (1) the 732 cation exchange resin has a dual role in the recycling process of used LiFePO4 cathode powder (leaching-adsorption) in the used LiFePO4 cathode powder recycling process. (2) The separation of the valued metals and the phosphoric acid can be achieved in one step using the 732 cation exchange resin.