Efficient Solid–Liquid Separation of Tailings and Tailwater Treatment: Mechanisms, Technologies, and Prospects

To address the challenges of poor settling performance of fine tailings and inefficient return−water treatment arising from increasingly low−grade, finely disseminated, and complex mineral resources, this paper systematically reviews recent advances in tailings solid–liquid separation and tailwater recycling technologies. Based on interfacial chemistry and colloidal stability theories, the mechanisms governing particle aggregation, sedimentation, and bed compression in multiphase systems are summarized. On this basis, a technological framework integrating chemical regulation, physical intensification, and intelligent optimization is proposed. Recent progress is reviewed in terms of functionalized flocculants, deep−cone thickening and mechanical dewatering, multi−field assisted strengthening technologies, and coupled computational fluid dynamics–population balance model (CFD–PBM) simulation. For thickened underflow, the evolution of rheological properties and its implications for paste backfill, dry stacking, and dust suppression are discussed. For overflow water, the migration and transformation of residual components, advanced purification methods, and the influence of water recycling on mineral processing performance are analyzed. Future research should focus on the green and targeted design of reagents, digital−twin−enabled solid–liquid separation systems, and full−life−cycle waste−to−resource strategies, so as to support the green and low−carbon development of the mining industry.