Integrated Hydrometallurgical Approaches for Sustainable Recovery of Metals from Lithium-ion Batteries Cathodes.

Abstract

This PhD thesis is focused on the leaching process of lithium-ion battery (LIB) cathodes to improve the recovery of metals contained in the batteries. Current LIB recycling methods primarily involve metallurgical processes. These techniques typically submit the batteries to mechanical and thermal pre-treatment to facilitate the dissolution step via acid leaching (hydrometallurgy). However, these processes are usually associated with high energy demand, water and reactants consumption, and the generation of large volumes of wastewater. Therefore, the hydrometallurgical process must be redesigned to become more sustainable. In this thesis, presented as a collection of five publications, different approaches were studied to enhance the leaching process of LIBs. In the first work, the electrodialysis technique was proposed to regenerate the acid consumed during the leaching process of LIBs cathode materials as well as to integrate the extraction and recovery step in a single stage. The second and third works studied the reaction mechanisms involved in the extraction of metals from LIB waste. In the fourth work, the kinetic leaching information obtained in the previous works was used to optimize the process's mass and time efficiency, modifying the reactor configuration. Finally, the fifth work was proposed to analyse using citric acid as a benign chemical to dissolve metal oxides from LIBs wastes.