• Bastnaesite flotation is reviewed from an interfacial-control perspective. • Selectivity losses are linked to ions, surface states, and gangue competition. • Advanced collectors and depressants are evaluated mechanistically. • Fine-particle, bubble-interface, and oxidation strategies are integrated. • A roadmap is proposed for robust and industrially relevant flotation. Bastnaesite is one of the most important rare-earth minerals and a major target of flotation beneficiation, yet its selective flotation remains challenging because of the limited accessibility of exposed rare-earth surface sites, strong competition with gangue minerals, and pronounced effects of dissolved ions, water chemistry, and surface-state changes on reagent adsorption. This review critically examines bastnaesite flotation from an interfacial-chemistry perspective, with emphasis on collector design, depressant action, additive-ion regulation, and process-assisted flotation strategies. Conventional collectors and depressants remain central to bastnaesite flotation, but their performance is strongly governed by adsorption configuration, pH-dependent speciation, dissolved-ion effects, and mineral-specific interfacial interactions. Recent studies suggest that flotation selectivity can be improved when reagent design and process control are guided by mechanistic understanding rather than empirical optimization alone. Accordingly, emerging strategies, including additive-ion regulation, modified and mixed collectors, novel depressants, fine-particle aggregation/dispersion control, bubble-interface engineering, and oxidative surface-state tuning, are discussed as promising routes to enhanced selectivity. Overall, the literature indicates a shift from conventional reagent optimization toward mechanism-guided interfacial engineering. At the same time, important challenges remain in translating laboratory-scale advances to complex ores, recycled-water systems, and fine-particle flotation. This review provides a mechanistically informed framework for understanding bastnaesite flotation and outlines research priorities for selective, robust, and industrially relevant rare-earth beneficiation.
Junhyun Choi (Sat,) studied this question.