The mechanism of surface activation in sphalerite by metal ions with d¹⁰ electronic configurations: Experimental and DFT study

The activation mechanism of metal ions with d(10) inert electronic configurations on sphalerite (ZnS) were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), and X-ray photoelectron spectroscopy (XPS), combined with density functional theory (DFT). Flotation experiments showed that the addition of activators increased sphalerite recovery by 50-70 %. The XPS results indicated that these inert cations with d(10) electronic configurations formed stable metal sulfides (Cu2S, CuS, Ag2S, CdS, and HgS) on the sphalerite surface. The FTIR results demonstrated that the activated sphalerite enhanced the adsorption stability of butyl xanthate on the sphalerite surface. DFT studies found that metal ion introduction reduced surface relaxation and decreased the band gap on the sphalerite surface, both of which increased butyl xanthate adsorption. Finally, it was suggested in this study that the energy required for the d(10) to d(9)s(1) electron transition and the polarization could be used to predict the potential sphalerite activator.