Abstract

The adsorption mechanisms of the collectors O-isopropyl-N-ethyl thionocarbamate (IPETC) and potassium amyl xanthate (PAX) on a covellite surface were studied through microflotation tests, Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations. The microflotation test demonstrated that the collectors have a marked effect on the covellite flotation and that covellite flotation is not pH-dependent. The FT-IR spectra for covellite treated with IPETC and PAX collectors at pH 8 and 11 does not differ significantly. For IPETC, the leading adsorption -C(=S) -NH group vibration was identified, and the NH stretching band is absent from both spectra. The spectra show the frequencies for the PAX, Cu-amylxanthate (CuAX), and (AX)(2) dixantogen that formed. The XPS spectra showed that the adsorption mechanism of PAX on the covellite surface is principally through C 1 s and S 2p. The adsorption mechanism of IPETC on the covellite surface suggests that the bond is enabled through the=S element of the collector with Cu atoms in the covellite surface. Finally, the DFT calculations predict that for IPETC the bond with copper only occurred through the C=S group. For PAX, the bond with copper occurred through the C=S and C=S groups.