In this work, the active sites and species involved in xanthate adsorption on sphalerite/marmatite surfaces were studied using adsorption capacity measurements, single mineral flotation, and time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis. The effects of Fe concentration on the xanthate adsorption capacity, Cu activation, and the flotation response of sphalerite/marmatite were determined. A discovery was that xanthate can interact with Fe atoms in the crystal of sphalerite/marmatite, as well as with Zn and Cu on the surface. We detected C₂S₂⁻ fragment ions from dixanthogen, and dixanthogen may have been adsorbed on the surface of marmatite. The amounts of Cu and copper xanthate adsorbed on the marmatite surface were lower than those on the sphalerite surface, because Fe occupies Cu and Zn exchange sites. These results help to address the long-standing controversy regarding the products and mechanisms of xanthate adsorption on Fe-bearing sphalerite surfaces.

The surface features of fluorapatite (FA, Ca₅(PO₄)₃F) and dolomite (CaMg(CO₃)₂) conditioned with sulfuric acid (H₂SO₄) were examined through flotation experiments, contact angle tests, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and FTIR experiments. The flotation and contact angle results suggested that oleate insufficiently adsorbed onto the H₂SO₄-treated FA surface such that the FA surface remained hydrophilic. However, using oleate as a collector, the recovery and hydrophobicity of H₂SO₄-treated dolomite were satisfactory. TOF-SIMS and FTIR studies indicated that sulfate anion bound with Ca atoms on the FA surface, which hindered oleate adsorption onto the FA surface. Meanwhile, sulfate anion and oleate species appeared on the dolomite surface, thereby generating a hydrophobic dolomite and also a satisfactory recovery.

In this work, a sulfidization mechanism of malachite was confirmed based on the depth profile product, principal component, and depth profile curve analyses of time-of-flight secondary ion mass spectrometry (TOF-SIMS). The results showed that Cu/S species, including fragment ion peaks of Cu₂S⁺, Cu₃S⁺, S⁻, HS⁻, S₂⁻, CuS₂⁻, and CuS₃⁻, were present in the inner layers of sulfidized malachite in the positive and negative spectral ranges 75–400 and 30–470 m/z. Na₂S reacted with the surface and inner atoms, causing simultaneous sulfidization of malachite on the surface and in the inner layers. The inner layer mainly contained positive fragment ions with large Cu/S ratios. In summary, the interlayer sulfidization phenomenon was confirmed and the differences in sulfidization products between the surface and inner layers were determined.