Flotation Performance and Adsorption Mechanism of a Novel Chelating Collector for Azurite

Abstract

Thiophosphate compounds have attracted much attention in coordination chemistry, but their deep adsorption mechanism remains underexplored as flotation collectors. The flotation performance and adsorption mechanism of a novel (dibutoxy-thiophosphorylsulfanyl)-acetic acid (CDDP) chelating collector on azurite surfaces were studied by micro-flotation tests, zeta potential measurements, and Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FE-SEM) analysis. The micro-flotation results indicated that CDDP exhibited superior collecting performances to direct flotation recovery of azurite and floated over 91.44% of azurite at pH 7. For sodium isopentyl xanthate (NaIX) and Benzohydroxamic acid (BHA) collectors, the addition of Na2S still did not show good collection performance. The results of zeta potential, FTIR, XPS and FE-SEM measurements, all confirmed that CDDP showed a better affinity to azurite surfaces than NaIX and BHA. Furthermore, XPS and FE-SEM provided obvious evidence that CDDP could easily react with Cu2+ sites on azurite surfaces. Using the density functional theory (DFT) method, the collection capacity of azurite was CDDP > BHA > NaIX, which exactly matched the micro-flotation results. In addition, this study provided an atomic-scale understanding of the structure–property relationship of CDDP as chelating agents for copper mineral flotation.