Characterization of sulfide film on smithsonite surface during sulfidation processing and its response to flotation performance

Improved Understanding of the Sulfidization Mechanism in Amine Flotation of Smithsonite: An XPS, AFM and UV–Vis DRS Study

“…One was contributed by the adventitious carbon contamination, consisting of the peaks at 284.80 eV (C-C, C=C and C-H) and the peaks at~286.30 eV (C−O single bond) [18][19][20]. Another, i.e., the peaks at~290.0 eV, was attributed to carbonate in the smithsonite lattice [2,11]. For further information, we recorded detail-scan XPS spectra of sample surfaces, including their C1s, O1s, Zn2p3 and S2p spectra.…”

“…Other XPS studies conducted by Feng and Wen [2], Luo et al [11] and Wu et al [13] showed the formation of polysulfide species, in addition to ZnS. Zeta-potential measurements, another surface-sensitive technology, have shown that the addition of greater amounts of Na 2 S makes the smithsonite zeta potential more negative and lowers its isoelectric point.…”

“…However, further activation using metal ions such as Cu 2+ and Pb 2+ is required when xanthate is used as a collector [7][8][9]. In general, sulfidization amine flotation can achieve better performance, resulting in its wide use in industrial production [10,11].…”

“…The authors attributed this behavior to the formation of ZnS via chemical reactions of HS − with the smithsonite surface (pH IEP (ZnS) ≈ 2; 6 ≤ pH IEP (ZnCO 3 ) ≤ 8) [5]. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis detected ZnS − , ZnS 2− , S − and S 2 − on the surfaces of sulfidized smithsonite samples; and the corresponding depth profile analysis showed that the sulfidization product film thickness can reach more 10 nm [11], suggesting that smithsonite sulfidization is not confined to the smithsonite-aqueous solution interface, but continues within the bulk of particles. Density functional theory calculations have also been carried out to study the sulfidization flotation of smithsonite [14][15][16].…”

“…Density functional theory calculations have also been carried out to study the sulfidization flotation of smithsonite [14][15][16]. Numerous studies have attempted to elucidate the sulfidization mechanism of smithsonite [2,11,[13][14][15][16]. However, most of them have only focused on the adsorption of sulfide or hydrosulfide ions on the smithsonite surface and failed to discuss the entire sulfidization process; little research has analyzed the crystal phase of the sulfidization product; in addition, a model of the sulfidized smithsonite particle has not been proposed yet.…”