Sustainable Flotation of Complex Copper-Nickel Sulfide Ores: A Review of Integrated Process Strategies

The sustainable beneficiation of copper-nickel sulfide ores is critical for the global energy transition, yet it is increasingly hindered by declining ore grades and complex mineralogy. This review summarizes recent advances in grinding and flotation technologies designed to overcome these challenges. A primary focus is placed on mitigating the detrimental effects of magnesium-bearing silicate gangues (e.g. serpentine, talc). These minerals impair process selectivity and recovery through deleterious surface interactions, slime coatings, and rheological complications, while high MgO content in concentrates penalizes downstream smelting efficiency and sustainability. We analyze an integrated suite of process engineering solutions across the value chain. These include: (1) advanced pre-concentration via sensor-based sorting for early gangue rejection; (2) energy-efficient comminution using high-pressure grinding rolls (HPGR) to optimize mineral liberation; and (3) innovative flotation strategies that leverage selective reagents, electrochemical potential control, and optimized circuit configurations. By synthesizing fundamental mechanisms with applied process innovations, this review provides a comprehensive roadmap for designing more efficient, selective, and environmentally sustainable flotation circuits for copper-nickel sulfide resources.