Mechanism of Disinhibition Activation of Na₂SO₃ and Cu²⁺ in Flotation Recovery of Sphalerite from Cyanide Tailings

Sphalerite is a crucial metal mineral in many gold cyanide leaching residue. The flotation recovery of cyanided sphalerite is challenging. Herein, we present a method to efficiently recover zinc resources from cyanide tailings using Na2SO3 and Cu2+ for the disinhibition activation flotation of cyanided sphalerite. Microflotation tests of pure minerals and closed-circuit flotation tests of real ore demonstrated that adding Na2SO3 can attenuate the adverse effects of CN– on the floatability of cyanided sphalerite. The flotation recovery of cyanided sphalerite increased through the synergistic effect of Na2SO3 and Cu2+. The surface detection results indicated that Na2SO3 induced the desorption of CN– from the surface of the cyanided sphalerite, thereby weakening the shielding effect of the Zn–CN components on the adsorption of collectors on the cyanided sphalerite surfaces. Additionally, after adding Na2SO3 and then Cu2+, more Cu–S active constituents were produced on the surface of the cyanided sphalerite instead of Cu–CN components, providing more active sites for the adsorption of collectors on the cyanided sphalerite surfaces. Thus, the ideal flotation of cyanided sphalerite was achieved after disinhibition activation by Na2SO3 and Cu2+. The current study is expected to serve as a reference for decision-makers when evaluating sustainable management options for cyanide tailings.