An efficient chalcopyrite depressant for Cu-Mo separation and its interaction mechanism: Adsorption configuration and DFT calculations

A small molecular triazole derivative called AMT (3-amino-5-mercapto-1,2,4-triazole) was explored as a novel and efficient chalcopyrite depressant in the preferential flotation of chalcopyrite from molybdenite. The flotation performances were comprehensively investigated via micro-flotation tests of singe and mixed minerals with and without Cu collector. The adsorption mechanisms were determined in terms of contact angle, adsorption capacity, and zeta potential, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and DFT calculations. Single mineral flotation results illustrated that the AMT selectively depressed chalcopyrite over a wide range of pH values. Particularly, AMT was able to depress chalcopyrite even in the presence of sodium isobutyl xanthate (SIBX). The contact angle, adsorption capacity, zeta potential, and FTIR results suggested that AMT was preferentially adsorbed on chalcopyrite surface, but it barely interacted with molybdenite. XPS tests and DFT calculations demonstrated that AMT was chemically adsorbed on chalcopyrite surface through the hybridization of S (1) and N (1) 2p orbitals of AMT with the Cu (1) 3d orbital. The bonding between S (1) atom and Cu (1) was much stronger than that between N (1) and Cu (1). Thus, AMT exhibited good potential as a novel depressant due to its excellent selectivity and practicability.