Influence of Ag, Sb, Bi and Zn impurities on electrochemical and flotation behaviour of galena

The influences of Ag, Bi, Sb and Zn impurities on the electrochemical adsorption of butyl xanthate on a galena surface were investigated. The impurity-doped and pure galena samples were synthesised by chemical precipitation and tested by X-ray diffraction (XRD) analyses. The flotation results suggest that the Ag and Bi impurities can promote the flotation of galena, while the Zn and Sb inhibit it. Both the lead- and impurity-xanthate are observed on the galena surface by infrared spectra, which suggests that the impurities on galena surface also interact with xanthate. However, Ag-xanthate and Bi-xanthate at the galena surface doped Ag or Bi may need to be further verified. The cyclic voltammetric measurements on galena microelectrodes reveal two oxidation peaks for both the pure and impurity-doped PbS, while no obvious reduction peaks are observed. It is found that the presence of Ag and Bi enhances the oxidation of xanthate on the galena surface, while the Zn and Sb impurities inhibit the oxidation of xanthate on the galena surface. The amount of electrochemically adsorbed xanthate on the galena surface varies based on the type of impurity and has a positive correlation with the flotation recovery of galena.