Optimized Partially Preferential Flotation of Low-Grade Cu–Ni Sulfide Ore

The efficient beneficiation of low-grade Cu–Ni sulfide ores is challenging because Cu-bearing and Ni-bearing sulfide minerals are finely intergrown with gangue minerals. In this study, the ore composition and mineral liberation characteristics were examined, and different flotation flowsheets were evaluated. A flotation feed containing 80% of particles finer than 0.074 mm was selected by balancing mineral liberation against the adverse effects of excessive fines. After flowsheet optimization, a partially preferential flotation strategy was adopted, in which most Cu was first recovered into a Cu concentrate, and the remaining Cu was recovered together with Ni in a Cu–Ni bulk concentrate. For the closed-circuit flowsheet, an economic Cu concentrate with a Cu grade of 20.65% and Cu recovery of 78.77%, and qualified Cu–Ni bulk concentrates with a Ni grade of 5.43% and Ni recovery of 61.99%, were obtained. The comprehensive recovery rate of Cu was 88%. Partially preferential flotation simplifies the separation flowsheet of Cu–Ni ores while achieving substantial recovery of valuable metals. The technology is highly efficient and economical, and has broad application prospects for the beneficiation of low-grade Cu–Ni sulfide ores.