Tiopronin as a novel copper depressant for the selective flotation separation of chalcopyrite and molybdenite

In this work, an environmental-friendly surfactant named tiopronin was tested as a novel copper depressant in copper-molybdenum sulfide separation for the first time. The separation performances were evaluated by micro-flotation and the depression mechanism was revealed by means of Zeta potential , Scanning Electron Microscope and Energy Dispersive Spectrometer (SEM-EDS), X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) measurements. The micro-flotation tests demonstrated that tiopronin exhibited powerful depressing effect on chalcopyrite and it could achieve satisfactory separation results with high selectivity in wide pH range. The novel depressant had promising application prospect due to its high selectivity and low toxicity in compared with conventional one. Zeta potential, SEM-EDS, XPS and ToF-SIMS measurements manifested that tiopronin was chemisorbed on chalcopyrite surface through the strong chemical reaction of copper sites with C O and SH groups in tiopronin molecular to form five-membered chelating rings. In addition, a possible depression model was proposed.