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 reducing environmental pollution and 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 principal reduction factors were also optimized. The results show that the spent cathode powder converts mainly to water-soluble Li2CO3, that the leaching selectivity of lithium is 100%, and that other metals can be separated by wet magnetic separation under optimal conditions. A reasonable explanation of the phase conversion during the reduction process is 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.