Utilization of Phytic Acid as a Selective Depressant for Quartz Activated by Zinc Ions in Smithsonite Flotation

It is difficult to separate smithsonite from quartz with metal ion activation through flotation using sodium oleate (NaOL) as the collector. The inevitable Zn²⁺ in the flotation process of zinc oxide ore makes the separation of smithsonite and quartz more difficult. Thus, this study investigated the use of phytic acid (PA) as a flotation depressant to separate smithsonite from Zn²⁺-activated quartz while utilizing sodium oleate as the collector. Microflotation tests indicated that phytic acid could selectively inhibit the flotation of Zn²⁺-activated quartz without affecting the flotation of smithsonite. The measured zeta potentials revealed that the existence of phytic acid hindered sodium oleate adsorption to the surface of Zn²⁺-activated quartz but had little influence on the adsorption of smithsonite. Zn²⁺ dissolution tests and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analysis indicated that the phytic acid could dissolve the Zn²⁺ from the minerals' surfaces into the solution. In conjunction with X-ray photoelectron spectroscopy results, the analysis indicated that phytic acid could adsorb onto the Zn²⁺-activated quartz surface and eliminate active sites for sodium oleate adsorption by dissolving the active Zn²⁺ from the quartz surface into the solution.