Fe-content-induced sphalerite electronic structure transformation and interaction difference with DSBDTP: experimental and DFT studies

This study systematically investigates Fe-content-induced electronic structures transformation and difference in flotation performance of sphalerite. DFT calculations demonstrate that rising Fe content narrows the bandgap and reduces the intensity of the Cu 3d orbital peak near the Fermi level and its hybridization with S atoms in the sphalerite, thereby reducing the reactivity of copper atoms and affecting the interaction between collector and copper-activated sphalerite surface. Flotation experiments further corroborate a decline in sphalerite recovery with increasing Fe concentrations. Adsorption analysis of the reagents on the surface confirmed that copper is the main adsorption site for sodium di-sec-butyl dithiophosphate (DSBDTP) on copper-activated sphalerite. However, as Fe content increases, the adsorption efficiency of CuSO₄ and DSBDTP weakens. The study also identifies that elevated Fe content lengthens the Cu-S bond, increases bond energy, and reducing the orbital hybridization strength between S₃₇ and Cu atoms. This weakened hybridization interaction diminishes the overall bonding strength between DSBDTP and copper-activated sphalerite. These findings provide critical insights into the detrimental effects of Fe impurities on sphalerite flotation.