Recycling of valuable metals from spent cathode material by organic pyrolysis combined with in-situ thermal reduction

• Published in: Journal of hazardous materials 2022-05, Vol.430, p.128374-128374, Article 128374
• Main Authors: Zhang, Guangwen, Liu, Zimeng, Yuan, Xue, He, Yaqun, Wei, Neng, Wang, Haifeng, Zhang, Bo
• Format: Article
• Language: English
• Subjects: Heating treatment; Organic removal; Spent lithium-ion batteries; Thermal reduction; Valuable metal recycling
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.128374

From the perspective of environmental protection and resource recovery, recycling of spent lithium-ion batteries is a meaningful process. In this study, the removal of organics, liberatioin of electrode material, and reduction of high valence transition metal, as the key points in recycling efficiency of valuable metals, have been firstly achieved simultaneously by low temperature heat treatment recycling process. Pyrolysis characteristics of organics, phase transition behavior of spent cathode material and the thermal reduction mechanism were evaluated in the meantime. Results demonstrate that organics can be removed and the liberation of electrode materials can be improved by pyrolysis. High-valence transition metals in cathode materials are synchronously reduced to CoO, NiO, MnO, Ni, and Co based on the reducing action of organics, aluminum foil and conductive additives. At the same time, Li element exists in the form of Li2CO3, LiF and aluminum-lithium compound that can be recycled by water-leaching in the water impact crushing process while transition metals can be recycled by acid leaching without reducing agents. 81.26% of Li can be recycled from water-leaching process while the comprehensive recovery rate of Ni, Co, Mn is 92.04%, 93.01%, 92.21%, respectively. This study may provide an environmentally-friendly recycling flowchart of spent lithium-ion batteries. [Display omitted] •Organics, aluminum foils and conductive additives play a role of reductant in thermal-reduction process.•Organic pyrolysis combined with in-situ thermal reduction can be used to recover Li and transition metals.•High-valence transition metals in cathode materials are synchronously reduced to CoO, NiO, MnO, Ni, and Co.