Flotation separation of molybdenite and talc by xanthan gum

In this study, the depressive effect of xanthan gum (XG) on molybdenite and talc flotation was studied using potassium butyl xanthate (PBX) as collector, and the mechanism through which molybdenite was separated from talc was investigated by Fourier transform infrared (FTIR) spectroscopy, Time-of-flight secondary ion mass spectrometry (TOF-SIMS), and X-ray photoelectron spectroscopy (XPS). The single mineral flotation experiments showed that both molybdenite and talc were depressed by XG in the absence of PBX. When PBX was used, molybdenite recovered its excellent floatability while talc was still depressed by XG. In artificial mixed minerals flotation experiment, the flotation recovery of molybdenite remained around 80% while that of talc was about 20% at pH 3–9. XPS analysis results showed that XG adsorbed on molybdenite “surface” by physical adsorption instead of chemical adsorption and hydrophobic interaction played a main role. The results of FTIR spectroscopy and TOF-SIMS indicated that the pre-adsorption of XG on molybdenite cannot hinder the further chemisorption of PBX on molybdenite “edge”, leading to the co-adsorption of depressant and collector on molybdenite surface. Because PBX has no collecting ability on talc, the flotation separation of molybdenite and talc was achieved through the collecting of molybdenite by PBX and the inhibiting of XG on talc. Molybdenite was floatable when XG adsorbed on “surface” and PBX adsorbed on “edge”. [Display omitted] •Both molybdenite and talc were depressed by XG in the absence of PBX.•PBX made molybdenite recover excellent floatability while talc was always depressed.•Flotation separation of molybdenite and talc was realized.•XG mainly adsorbed on molybdenite “surface” by hydrophobic interaction.•XG on molybdenite “surface” cannot hinder chemisorption of PBX on molybdenite “edge”.