Enhancing the Flotation Separation of Galena and Pyrite in the Presence of Seawater

The effect of seawater on the flotation of sulfide minerals is a hot research topic at the present. Using seawater instead of fresh water to separate lead-sulfur can save fresh water resources and reduce lime consumption, which has broad prospects in terms of economic and environmental protection. Many studies have shown that divalent calcium and magnesium ions in seawater are hydrolyzed to form hydroxyl complexes under alkaline pH values, which affects the flotation separation of sulfide ore. In this paper, the flotation separation of galena and pyrite in seawater was tested, and the mechanism was analyzed. Compared with that in deionized water, the lead grade of concentrate in seawater flotation increased from 57.40 to 60.20%. Meanwhile, the recovery of galena declined from 68.66 to 61.17%, and the SI value increased from 2.020 to 2.072. With the addition of SHMP, SS, and EDTA, the SI value increased from 2.072 to 2.609, 2.525, and 2.287, respectively. Noteworthily, when EDTA was excessive, the grade of Pb was 69.60%, and the SI value was 3.050. Wettability analysis, zeta potential analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, density functional theory calculation, and E-DLVO calculation verified the microflotation results and revealed the mechanism of action.