LAUSR

The depression performance and mechanism of the combined depressant containing potassium ferricyanide (K3[Fe(CN)6]), zinc sulfate (ZnSO4), and sodium carbonate (Na2CO3) with potassium isobutyl xanthate (PPBX) as the collector in a mixed Pb–Zn sulfide flotation system were investigated using microflotation experiments, contact-angle experiments, adsorption capacity experiments, and scanning electron microscopy (SEM)–energy-dispersive spectroscopy (EDS) analysis. The microflotation results indicated that the combined depressant has a significant selective depression effect on sphalerite but a small effect on galena. When the dosages of K3[Fe(CN)6], ZnSO4, and Na2CO3 were 1.8 × 10−5 mol/L, 8 × 10−5 mol/L, and 2.4 × 10−4 mol/L, respectively, the recovery of galena was 92.56%, whereas that of sphalerite (Pb2+ activation) was only 7.65%. The contact-angle experiment indicated that the order of the single depression effect was as follows: K3[Fe(CN)6] > ZnSO4 > Na2CO3. The depression effect of the combined depressant was significantly better than the single depression effect. Adsorption capacity results demonstrated that after depressant addition, the decreasing order of xanthate adsorption capacity was as follows: ZnSO4 + Na2CO3 > K3[Fe(CN)6] + Na2CO3 > K3[Fe(CN)6] + ZnSO4 > K3[Fe(CN)6] + ZnSO4 + Na2CO3. Scanning electron microscopy–energy-dispersive spectroscopy results showed that depression of sphalerite (Pb2+ activation) by the combined depressant generated numerous precipitates.