Experimental and theoretical studies on the effect of Fe3+ on the surface properties and floatability of chalcopyrite

Wastewater from mineral processing plants is often treated, recovered, and recycled. The high concentration of iron ions in the recycled water affects the flotation of chalcopyrite. Therefore, studying the impact of introducing Fe³⁺ in different collector systems on the flotation behavior of chalcopyrite has guided in realizing its efficient recovery. The results show that both collectors can effectively promote flotation recovery. When the Fe³⁺ concentration exceeds 40 mg/L, the flotation recovery decreases significantly. Surface property analysis shows that kerosene and Z-200 act on the surface of chalcopyrite through physical adsorption and chemical adsorption, respectively. The hydroxyl iron formed after introducing Fe³⁺ is the crucial reason the surface hydrophobicity decreases and potential increases. DFT calculation results further demonstrate that Z-200 can form stable Cu-S bonds with Cu sites on the surface of chalcopyrite. –OH and Fe in the hydroxyl iron (Fe(OH)₂⁺ and Fe(OH)₃) generated after the introduction of Fe³⁺ can bond with Cu and S on the mineral surface, respectively. Because hydroxyl iron competes with the collector for adsorption, preferentially adsorbed on the surface of chalcopyrite reduced the flotation recovery. The results of this study provide theoretical support for reducing the impact of iron ions on chalcopyrite flotation.