Interfacial adsorption and reactivity of exact separation of sphalerite and pyrite by ferrophilic inhibitors in EX−Cu(II) system

Tetrasodium iminodisuccinate (IDS) was used as an inhibitor in the separation of sphalerite and pyrite in the EX−Cu(II) (ethyl xanthate and Cu²⁺) system. The flotation test results demonstrated that IDS can effectively separate sphalerite and pyrite under low alkaline conditions. Furthermore, high-quality zinc concentrates with a Zn grade of 58.48% and a recovery of 91.24% through mixed mineral flotation were obtained. The fundamental mechanisms were investigated through surface wettability tests, adsorption capacity tests, LEIS, FTIR, and XPS. The results confirmed that IDS prevents the adsorption of EX on the surface of pyrite, thereby reducing the response and reactivity of pyrite. The introduction of IDS causes the detachment of Cu²⁺ from the Cu-activated pyrite surface. This process allowed IDS to chelate with the Fe sites on the surface of pyrite through the —COO— and N-centered active groups. By contrast, IDS exhibits weaker adhesion on the surface of Cu-activated sphalerite, making it easily displaced by EX through competitive adsorption.