Fine-Grained Complex Refractory Phosphate Ore Mineral Separation: Research Progress and Future Development Trends

As high-grade and coarse-grained phosphate resources are progressively depleted, the efficient beneficiation of fine-grained phosphate ores, typically below 74 μm and especially below 25 μm, has become critical for securing the global phosphorus supply. However, such ores present substantial processing challenges owing to their large specific surface area, high surface energy, and complex intergrowth with carbonate, silicate, and iron–aluminum oxide gangues. This review provides a systematic overview of current beneficiation approaches, including flotation, gravity concentration, magnetic separation, electrostatic techniques, and their integrated flowsheets. Particular attention is paid to reagent systems comprising novel collectors, depressants, and dispersants; equipment innovations such as flotation columns, centrifugal separators, and micro–nano bubble generators; interfacial chemistry regulation; and process optimization strategies. Key technical barriers are critically analyzed, including slime coating, particle agglomeration, low collision efficiency, and insufficient reagent selectivity. Emerging research directions are summarized, covering bio-based reagents, nanotechnology, in situ characterization, and artificial-intelligence-driven process control. This review demonstrates that double reverse flotation and desliming–double reverse flotation remain the most effective industrial flowsheets, while nanobubbles and novel organic depressants have shown promising laboratory-scale improvements in fine particle recovery. The overriding challenge remains that 10%–30% of fine phosphate is still lost to tailings in current industrial practice, mainly because ultrafine grinding generates excessive secondary slimes that consume large reagent dosages and reduce separation selectivity. Future priorities should therefore focus on energy-efficient flotation equipment for fine particles, intelligent process control, and environmentally benign reagent systems based on precise interfacial chemistry, so as to achieve economically and environmentally sustainable recovery of fine-grained phosphate ores.