A Copper–Amine Complex as an Activator for Sphalerite Flotation

Sphalerite (ZnS), the primary zinc-bearing mineral in most sulfide deposits, exhibits poor natural floatability and requires activation by metal ions such as Cu2+ or Pb2+. Copper sulfate (CuSO4) is the most common activator, but its use at high dosages introduces sulfate accumulation and necessitates separate pre-conditioning to prevent the formation of inactive copper xanthates. This study investigates a novel copper–amine complex, Zn Flooter (ZnFL), as an alternative activator for sphalerite flotation. ZnFL is a liquid reagent containing stabilized ionic copper with a significantly lower sulfate content. Contact angle and flotation tests were conducted on two sphalerite-bearing ores of different mineralogy (Pb–Zn and Cu–Zn types). Contact angle tests showed that ZnFL (68–71°) enhances sphalerite surface hydrophobicity more effectively than CuSO4 (61–66°). In flotation, ZnFL at 100 g/t achieved recoveries and grades comparable to those for CuSO4 at 500 g/t, while allowing simultaneous addition with the collector without loss of performance. ZnFL also exhibited improved sphalerite/pyrite selectivity and did not negatively affect froth stability. These results demonstrate that ZnFL can provide equivalent or superior activation efficiency at a lower dosage and with simplified operation. Further studies on adsorption mechanisms and water chemistry effects are recommended to validate its industrial potential as a sustainable activator for sphalerite flotation.