A novel selective galena collector based on modified dithiophosphate in Pb-Zn flotation separation and its adsorption mechanism

In this paper, a novel selective galena collector, called S-benzoyl-O, O’-dibutyl dithiophosphate (BDTP), was synthesized via an one-pot reaction with ammonium dibutyl dithiophosphate (DTP) and benzoyl chloride as initial raw materials, and was innovatively used in Pb-Zn flotation separation. Its flotation performances and adsorption mechanism on galena surface were detailly studied. The micro-flotation results illustrated that BDTP exhibited superior selectivity and collecting power over the conventional collectors (sodium isobutyl xanthate (SIBX) and sodium diethyldithiocarbamate (DTC)), realizing the effective flotation separation of galena and sphalerite at pH around 9.0 with ZnSO4 and Na2SO3 as modifiers. The contact angle (CA) results demonstrated that the treated galena surface by BDTP was more hydrophobic than that of sphalerite. Scanning electron microscope-Energy dispersive X-ray spectroscopy (SEM-EDS) results also told us BDTP had been adsorbed on galena surface successfully. In addition, FTIR and X-ray Photoelectron Spectroscopy (XPS) analysis results suggested that the interaction of BDTP with galena may be dominated by the chemisorption. The BDTP may act as a bidentate ligand, bonding with Pb atoms on galena surface via S atoms in the P=S group or O atoms in the C=O group to form two different adsorption geometries, which are a six-membered ring structure with one Pb atom and a “bullet”-shape complex with two different Pb atoms.