With the growing strategic importance of rare earth elements (REEs) and the urgent demand for red mud resource utilisation, efficient REE extraction from red mud has become a prominent research hotspot. This review systematically clarifies the occurrence modes, content distributions and chemical properties of typical REEs (e.g. La, Y and Sc) in red mud, and comprehensively summarises research advances in mainstream and emerging recovery technologies, including chemical leaching, bioleaching, pyrometallurgy, ion exchange and combined processes. A multidimensional evaluation framework covering recovery efficiency, optimal reaction conditions and environmental impact is established. Core performance indicators of mainstream processes are quantified, enabling systematic technical and environmental comparisons. Targeted process applicability for Bayer, sintering and combined red mud is clarified. Key technical bottlenecks are identified: difficult dealkalisation, radioactive impurity separation challenges and poor economic viability, alongside limitations of current dealkalisation processes, low leaching selectivity and scaling-up challenges. Finally, future research directions and actionable industrialisation strategies are proposed, aiming to provide systematic theoretical support and practical guidance for REE extraction from red mud.
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