Identification of sulfidization products formed on azurite surfaces and its correlations with xanthate adsorption and flotation

Azurite is an important copper oxide mineral, the reserves of which in ores are second only to that of malachite. However, malachite is commonly used as a representative of copper oxide mineral, and few investigations on azurite flotation was conducted. In this study, for the first time, the sulfidization products formed on azurite surfaces were identified and correlated with the mineral's flotation recovery, using micro-flotation experiments, X-ray photoelectron spectroscopy, Fourier-transform infrared analysis, ultraviolet spectroscopy and time-of-flight secondary ion mass spectrometry. The micro-flotation experiments indicated that the addition of Na2S prior to collection increased azurite flotation recovery, and that recovery was significantly correlated with the pH of the pulp. The XPS results demonstrated that the sulfidization products formed on the azurite surface were copper monosulfides and polysulfides together with smaller amounts of oxysulfides. FT-IR and UV analyses determined that the treatment of the azurite with Na2S improved the adsorption stability of xanthate and also increased the amount adsorbed on the mineral surface. The copper sulfide species formed on the azurite surface were identified by XPS and confirmed using ToF-SIMS.