Degradation mechanism of surface sulfidization and hydrophobicity by Fe (III) in the flotation of cerussite

Unavoidable metal ions commonly exist in the pulp during flotation. These ions can affect the floatability of minerals, and they can also result in the differences in the surface features between different minerals. In this study, how Fe3+ affected the flotation behavior of cerussite was investigated by micro-flotation tests. The corresponding adsorption characteristics of the sulfidizing agent and collector on the surfaces of cerussite were investigated by surface-analysis techniques. The results of micro-flotation tests showed that the floatability of cerussite significantly decreased when Fe3+ was added before Na2S and xanthate. The flotation recovery of cerussite decreased compared with that obtained without participation of Fe3+. Additionally, the results of xanthate and Na2S adsorption tests, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and zeta potential measurements verified that Fe3+ and its hydrophilic hydroxyl derivatives (Fe-OH compounds) resulted in reduced amounts and reactive activities of S-bearing species adsorbed on the surfaces of cerussite. This decreased the adsorption capacity of subsequently added xanthate, resulting in the difficulty in effectively recovering cerussite in the sulfidization-xanthate system.