Green collaborative recycling of spent NCM cathode and waste sodium sulfate via an unconventional process

Abstract

Spent lithium-ion battery and waste sodium sulfate are hazardous solid wastes containing heavy metals and organic pollutants, both of which are difficult to dispose of safely. Here, we propose a collaborative disposal process to selective sulfidize spent lithium battery ternary material (NCM) with waste sodium sulfate by roasting, in which the Li in NCM is converted to water-soluble carbonate, manganese to acid-soluble oxides, and nickel and cobalt to insoluble sulfides. This favors the selective separation of valuable metals by stepwise leaching. Meanwhile, waste sodium sulfate provides essential sulfur and sodium sources, promoting selective sulfidation and grain growth to facilitate subsequent stepwise leaching. About 92.10 % of Li is extracted from the roasted sample after water leaching and 97.67 % of Mn is selectively extracted from the water leaching residue after the acid leaching. The nickel and cobalt are concentrated into the acid leaching residue, which can be used to directly produce commercial NCM materials. This study provides technical support for the short-flow recycling of spent lithium-ion batteries without conventional solvent extraction processes.