Investigation of flotation bubble-particle attachment interactions influenced by monovalent cations and cationic surfactants from macro and molecular scales

The objective of this study was to investigate how the synergistic interaction between monovalent sodium or potassium ions and cationic collectors could affect the efficiency of low-rank coal (LRC) flotation . Analytical techniques, such as Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and molecular dynamics simulations (MDS) were utilized. The results indicated that at a collector concentration of 10 -2 mol/L, the flotation performance was impeded to varying degrees in both sodium and potassium ion solutions, except for the collector dodecyl trimethylammonium chloride (DTAC). Furthermore, combining sodium ions with DTAC and dodecylamine (DDA) with potassium ions significantly enhanced the flotation responses of the coal particles. The treatment with cationic surfactants reduced the degree of aromatic ring condensation on the surface, minimally affecting the overall content of oxygen-containing groups, though the types of these groups were significantly changed. The MDS analysis indicated that the adsorption of cationic collector molecules on the surface was mainly regulated by van der Waals forces rather than electrostatic interactions. This study can enhance our knowledge of how monovalent cations and cationic surfactants can affect the interactions involved in flotation bubble-particle attachment.