Lead ion modification and its enhancement for xanthate adsorption on smithsonite surface

In this study, the interaction between Pb ions and a smithsonite surface was investigated, and its effect on the xanthate adsorption of a mineral surface was evaluated. Micro-flotation tests indicated that the smithsonite flotation in a PbNO3 solution (5 × 10−5 mol/L) was approximately doubled with respect to that without Pb ion modification, where the xanthate functioned as a collector. The results of inductively coupled plasma mass spectroscopy suggested that the modification of Pb ions can be achieved via ion adsorption and exchange on the mineral surface. The potential structure of a Pb-modified smithsonite surface was investigated via Visual MINTEQ and X-ray photoelectron spectroscopy. During the modification, large amounts of Pb species, including PbCO3 and Pb3(CO3)2(OH)2, were formed on the smithsonite surface. The results of Fourier transform infrared spectroscopy and time-of-flight secondary-ion mass spectrometry indicated that Pb modification increased the number of active Pb sites for xanthate adsorption to improve the formation of hydrophobic Pb-xanthate precipitate. The adsorption tests revealed that Pb modification enhanced the stability of the xanthate products on the smithsonite surface. Therefore, the interaction of Pb ions with the smithsonite surfaces enhanced the strength and stability of the hydrophobic layer, resulting in the enhanced hydrophobization of smithsonite. [Display omitted] •Pb ions are beneficial to the smithsonite flotation, when xanthate as a collector.•Lead-ion modification can form stable lead species on the smithsonite surface.•Pb modification increases xanthate adsorption and enhances the Pb-xanthate stability.