Extraction of Valuable Metals from Spent Cathode Materials by Reductive Roasting in Methane Atmosphere

Abstract

Against the backdrop of the increasing amounts of lithium-ion batteries, it is not only reducing environmental pollution, but also relieving the stress on resource requirements through the sustainable recycling of spent lithium batteries. Here we targeted the reduction of the material phase by methane roasting and then achieved a step separation of Li, Ni, Co and Mn by differentiation in water solubility and magnetic strength. The main reduction factors were also optimized. The results show that the spent cathode powder is mainly converted to water-soluble Li2CO3 with 100% leaching selectivity of lithium and that other metals could be separated by wet magnetic separation under optimal conditions. A reasonable explanation of the phase conversion during the reduction process was provided and a preliminary process evaluation is presented at the end. Notably, this work has the strengths of step recovery of elements, rapid processing and zero chemical use, which has great potential for the industrial recycling field and provides a new idea for the development of green and efficient valuable metal recovery technologies for spent LIBs.

Keywords: spent lithium-ion batteries, Cathode material, Methane reduction, Step recovery, Wet magnetic separation