The efficient recovery of molybdenite fines using a novel collector: Flotation performances, adsorption mechanism and DFT calculation

• NBPT could achieve a satisfactory floatability of molybdenite fines. • NBPT preferentially adsorbed on the edges through chemical adsorption . • The S 3p orbital of NBPT hybridized with the Mo 4d orbital. • NBPT selectively adsorbed on hydrophilic edges and rendered them hydrophobic. In this work, a novel collector N-( N -butyl) thiophosphoric triamide (NBPT) was explored to improve the flotation of molybdenite fines. The flotation performance was evaluated through micro-flotation tests, and the interaction mechanism was investigated through Zeta potential, Fourier Transform Infrared Spectrometer (FTIR), adsorption capacity, Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), Atomic Force Microscopy (AFM) and density functional theory (DFT) calculations. Flotation results manifested NBPT could greatly improve the flotation of molybdenite fines. Zeta potential, FTIR, adsorption capacity and AFM measurements proved NBPT was more inclined to adsorb on molybdenite surface. XPS and ToF-SIMS analysis showed NBPT chemically adsorbed on molybdenite surface via the bonding between P S groups with Mo atoms. DFT calculations reconfirmed NBPT had much stronger affinity towards edges ( Eads = -657.69 kJ/mol) than faces ( Eads = -39.96 kJ/mol). Moreover, NBPT strongly interacted with molybdenite edges through the hybridization of the S 3p orbital of NBPT with the Mo 4d orbital of molybdenite to form strong covalence bond. As a result, NBPT could be utilized as a potential collector to enhance the flotation of molybdenite fines.