Mechanism of Glutathione as a Novel Sphalerite Depressant in Lead-Zinc Flotation Separation

Galena and sphalerite are the main sources of lead and zinc metals, and they are often closely symbiotic in nature. At present, the flotation method is the mainstream method to separate the two, but it faces a key problem: the lead ions produced by the dissolution of galena will activate the surface of sphalerite, making it more floatable and difficult to suppress. Therefore, how to effectively inhibit the activated sphalerite and achieve efficient separation of lead and zinc has always been a research hotspot in the field of sulfide ore flotation. On this basis, the green and environmentally friendly reagent glutathione (GSH) was applied to the flotation separation of sphalerite and galena for the first time in this study. Microflotation tests show that GSH can effectively inhibit sphalerite activated by lead ions and achieve efficient flotation separation of lead and zinc. The results of contact angle and zeta potential showed that GSH could significantly reduce the contact angle and surface zeta potential of sphalerite activated by lead ions, but had little effect on galena. FTIR results showed that GSH may be chemically adsorbed on the surface of sphalerite through COO- and C-N groups. XPS and ToF-SIMS results showed that GSH mainly coordinated with Zn2+ on the surface of sphalerite through COOH and C-N/-NH in the molecule to form GSH-ZnS complexes, thereby inhibiting sphalerite activated by lead ions.