Effect of dissolved unavoidable ions (Fe3+) from iron-containing gangue minerals on dispersion behavior of zinc oxide ore

With the decrease in zinc mineral resources, the secondary resource utilization of zinc tailings has attracted more attention all over the world. However, zinc oxide tailings contain many soluble minerals (limonite, pyrite), resulting in many metal ions interacting with the mineral surface. The effect of unavoidable ions (Fe3+) has become one of the challenges for the efficient separation and recovery of fine zinc oxide. Therefore, it is necessary to identify the effect of Fe3+ on the dispersion behavior of zinc oxide in order to improve the sorting efficiency and effective recycle of secondary resources. This study investigated the effect of Fe3+ on the dispersion behavior of fine smithsonite (zinc oxide). The turbidity experimental results showed that the turbidity of smithsonite was well dispersed in the deionized water, and decreased continuously with the addition of Fe3+. The smithsonite dispersion behavior was damaged by 5 x 10-4 mol/L Fe3+ from pH = 4 to 12. The results of zeta potential showed that the isoelectric point of smithsonite shifted positively from pH = 7.5 to 9.5. X-ray photoelectron spectroscopy (XPS) and solution chemistry analysis indicated that smithsonite was subjected to the action of Fe3+ to generate metal hydroxyl complexes or precipitates. The inter-particle interaction potential barrier of smithsonite at pH = 4 and 10 was 5.745 x 10-19 J and 2.31 x 10-19 J by calculations of DLVO theory, respectively. However, the potential energy of inter-particle interaction between smithsonite particles was less than zero in the presence of Fe3+, which indicated that the presence of iron ions disrupts the dispersion behavior of smithsonite. This study could provide theoretical guidance for the efficient recovery of secondary zinc re-sources from zinc oxide tailings.