Article ID Journal Published Year Pages File Type
593449 Colloids and Surfaces A: Physicochemical and Engineering Aspects 2013 10 Pages PDF
Abstract

•Quantum-chemical parameters of four thiophosphorus collectors using DFT.•Chemical reactivity of DIBDTPI, DIBMTPI, DIBDTPA or DIBMTPA in aqueous phase.•Structure-activity relationship of four collectors to metal or mineral surfaces.•Excellent agreement of model prediction with adsorption and flotation.

Thiophosphorous compounds: diisobutyl dithiophosphate (DIBDTPA), diisobutyl dithiophosphinate (DIBDTPI), diisobutyl monothiophosphate (DIBMTPA) and diisobutyl monothiophosphinate (DIBMTPI) are widely used as flotation collectors and corrosion inhibitors, though the true nature of their bonding mechanisms to solid surfaces is still unclear. Using density functional theory (DFT) calculations, this study investigates the structure-reactivity relationship of these thiophosphorus molecules as flotation collectors with sulfide minerals. The results indicate that the O atom(s) bonded to the P atom in thiophosphorus molecules can significantly impact the chemical reactivity of the S atom(s) in the four reagents, and for DIBMTPA and DIBMTPI, they could even attend the chemical bond formation with metal atoms. The reactive power of the four compounds to mineral surfaces of Cu, Au, Ag and Pb sulfides is predicted to be DIBDTPI ≫ DIBMTPI ≥ DIBDTPA > DIBMTPA, and their flotation selectivity against pyrite and sphalerite is suggested as DIBDTPA < DIBDTPI < DIBMTPI < DIBMTPA. Moreover, the thione form of acid or ion species of DIBMTPA or DIBMTPI is more stable than its thiol form, and in aqueous phases, the ionized thione of the four thiophosphorus collectors exhibits the strongest affinity to mineral surfaces. The theoretical results provide an atomic level understanding of the adsorption activity and selectivity of the four thiophosphorus molecules to metal sulfide minerals and a potential approach to molecular design of new thiophosphorous compounds for improving the flotation recovery of them.

Graphical abstractThe potential electron transfer between a sulfydryl collector and a sulfide mineral surface: E – energy, CB – conduction band, VB – valence band. The red arrow represents normal covalent bond while the green arrow indicates back donation covalent bond.Figure optionsDownload full-size imageDownload as PowerPoint slide

Related Topics
Physical Sciences and Engineering Chemical Engineering Colloid and Surface Chemistry
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