Novel 3-Tetradecylamine Propyl Amidoxime Collector for Selective Adsorption on the Surface of Smithsonite for Flotation Separation of Smithsonite from Calcite

Smithsonite has similar physicochemical properties and floatability to calcite, which makes it difficult to achieve flotation separation of smithsonite from calcite with conventional collectors. In this article, a novel 3-tetradecylamine propyl amidoxime (TPA) collector was prepared for the flotation of smithsonite. The microflotation experiments showed that the recovery of smithsonite could reach 93.5% at a dosage of 4.0 x 10-4 mol/L of TPA under neutral conditions, while the recovery of calcite was only 20.5%, which demonstrated excellent collection ability and selectivity. The adsorption mechanism of TPA with smithsonite was investigated by further experiments. The contact angle test indicated that TPA could increase the contact angle of smithsonite from 34.1 to 119.9(degrees), significantly enhancing its surface hydrophobicity. It was concluded from the zeta potential test that the TPA adsorbed on smithsonite could increase its positive potential but had no significant effect on calcite. Density functional theory calculations revealed that the TPA has very low HOMO and LUMO values, thus the adsorption of the -C(NOH)N+H3 group on the surface of smithsonite surface is formed by electrostatic interaction, while Fourier transform infrared spectroscopy showed that the adsorption is selective for smithsonite. Therefore, this work is expected to provide an efficient collector for the purification of smithsonite ore and shows great potential for environmental protection and mineral resource recycling.