Enhanced sulfidization of azurite surfaces by ammonium phosphate and its effect on flotation

Although azurite is one of the most important copper oxide minerals, the recovery of this mineral via sulfidization-xanthate flotation is typically unsatisfactory. The present work demonstrated the enhanced sulfidization of azurite surfaces using ammonia phosphate ((NH4)(3)PO4) together with Na2S, based on micro-flotation experiments, time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), zeta-potential measurements, contact angle measurements, Fourier-transform infrared (FT-IR) spectroscopy, and ultraviolet-visible (UV-Vis) spectroscopy. Micro-flotation experiments showed that the floatability of azurite was increased following the simultaneous addition of (NH4)(3)PO4 and Na2S. ToF-SIMS and XPS analyses demonstrated the formation of a high content of S species on the azurite surface and an increase in the number of Cu(I) species after exposure to (NH4)(3)PO4 and Na2S, compared with the azurite-Na2S system. The zeta potential of azurite particles was negatively shifted and the contact angle on the azurite surface was increased with the addition of (NH4)(3)PO4 prior to Na2S. These results indicate that treatment with (NH4)(3)PO4 enhances the sulfidization of azurite surfaces, which in turn promotes xanthate attachment. FT-IR and UV-Vis analyses confirmed that the addition of (NH4)(3)PO4 increased the adsorption of xanthate with reducing the consumption of xanthate during the azurite flotation process. Thus, (NH4)(3)PO4 has a beneficial effect on the sulfidization flotation of azurite.

Automated summary

This study demonstrates that the addition of ammonium phosphate and sodium sulfide enhances the sulfidization of azurite surfaces, improving the flotation performance of azurite in sulfidization-xanthate flotation.