Critical review of lithium recovery from spent aluminum electrolyte: Mechanisms, economics, and environmental assessment

SAE (spent aluminum electrolyte), a lithium-rich solid waste generated during aluminum electrolysis, contains more lithium than low-grade lithium ores and thus represents a promising secondary resource for lithium recovery. This review begins with a bibliometric analysis of SAE-related lithium recovery research, summarizing publication trends, research hotspots, and leading institutions in recent years. The chemical composition and elemental origins of SAE are then systematically examined. Current lithium extraction technologies—encompassing hydrometallurgical and combined pyro-hydrometallurgical processes—are critically reviewed, with a focus on impurity removal strategies for fluorine, aluminum, calcium, and magnesium, and their respective impacts on downstream lithium recovery efficiency. A techno-economic analysis (TEA) was performed for the treatment of 1 ton of SAE. In parallel, a life cycle assessment (LCA) was conducted to compare the environmental impacts of SAE-based lithium extraction with those of traditional ore-based processes. Finally, recommendations for process optimization are proposed, providing insights into the industrial application of SAE-based lithium recovery.