Vacuum separation behavior of polymorphic metal in waste Li-ion battery Al slag

• Published in: Vacuum Vol. 239; p. 114406
• Main Authors: Liang, Biao, Gao, Zhe, Li, Shaoxiong, Yang, Weichen, Deng, Linxing, Tao, Yuan, Kong, Xiangfeng, Yang, Bin, Liu, Dachun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2025
• Subjects: Green recycling; Li-ion battery Al slag; Resourceful disposal; Vacuum separation; Green recycling; Li-ion battery Al slag; Vacuum separation; Resourceful disposal
• ISSN: 0042-207X
• DOI: 10.1016/j.vacuum.2025.114406

Waste Li-ion battery Al slag (WLAS) is a substance that combines the characteristics of valuable secondary resources and hazardous solid waste. Traditionally chemical conversion treatments pose potential hazards to ecosystems, resulting in lower resource utilization rates and higher energy consumption. In this investigation, vacuum metallurgical techniques were strategically employed, leveraging the distinct volatilization and melting behaviors of constituent elements, to systematically examine the gas-phase separation theory of volatile metallic components and the vacuum melting behavior of refractory metals in WLAS. Thermodynamic analysis encompassing phase transition Gibbs free energy (ΔG), saturated vapor pressure, and maximum volatilization rates substantiated the technical feasibility of Al purification and impurity metal separation through vacuum processing. Experimental findings demonstrated that Al formed a stable metallic melt, with 98 % purity Al being directly recovered from WLAS at 1550 K. Conversely, Zn, Na, Ga, and Pb underwent complete solid-gas phase transitions, enabling their effective separation through volatilization. Fe, Cu, and Ni, exhibiting similar metallurgical behavior to Al, were concentrated in the residual phase through liquid-liquid phase separation. This promising approach not only enabled the environmentally safe disposal of WLAS but also ensured the effective recovery of sustainable Al resources. •The feasibility of WLAS vacuum separation was explored theoretically.•Vacuum separation behavior of polymorphic metal in WLAS was revealed scientifically.•Physical extraction of Al and enrichment of polymorphic metal have been achieved.•Make great significance to realize the harmless disposal and green recycling of WLAS.