Design and flotation performance of a novel hydroxy polyamine surfactant based on hematite reverse flotation desilication system

Based on the surface difference of hematite and quartz in solution, a hydroxyl-containing polyamine cationic surfactant was designed and screened with the assistant of computer simulation (molecular dynamics (MD) simulation and density functional theory (DFT) calculation) to enhance the separation efficiency in the reverse flotation system of hematite ore. And then N,N-dimethyl-N'-(2-hydroxyethyl)-N'-dodecyl-1.3-propanediamine (DMPDA) was synthesized in the laboratory. The computer simulation showed that the collecting ability of DMPDA would be comparable with that of N-dodecyl-1,3-propanediamine (NDEA) and N,N-Dimethyl-N'-dodecyl-1,3-propanediamine (DPDA), while a better selectivity than that of DPDA and dodecylamine (DDA) could be obtained. The flotation performance and mechanism were studied by flotation tests, zeta potential measurements, Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results of the flotation tests showed that DMPDA had a higher selectivity than DDA, which was in agreement with the theoretical prediction. The results of zeta potential, FTIR spectra, and XPS showed that DMPDA was adsorbed on the mineral surface mainly by electrostatic and hydrogen bonding. The introduction of the hydroxyl group could enhance the surface activity of the collector and the selective adsorption on the desired mineral surface. Based on this, a promising method for designing and screening the novel high-efficiency cation collector was proposed, which could accelerate the research and development of the cationic collectors. (C) 2019 Elsevier B.V. All rights reserved.