Physical and Chemical Analysis of Elemental Sulfur Formation during Galena Surface Oxidation

Abstract

The surface oxidation of sulfide minerals, such as galena (PbS), in aqueous solutions is of critical importance in a number of applications. A comprehensive understanding of the formation of oxidation species at the galena surface is still lacking. Much controversy over the nature of these oxidation products exists. A number of oxidation pathways have been proposed, and experimental evidence for the formation of elemental sulfur, metal polysulfides, and metal-deficient lead sulfides in acidic conditions has been shown and argued. This paper provides further insight into the electrochemical behavior of galena at pH 4.5. Utilizing a novel experimental system that combines in situ electrochemical control and AC mode atomic force microscopy (AFM) surface imaging, the formation and growth of nanoscopic domains on the galena surface are detected and examined at anodic potentials. AFM phase images indicate that these domains have different material properties to the underlying galena. Continued oxidation results in nanoscopic pitting and the formation of microscopic surface domains, which are confirmed to be elemental sulfur by Raman spectroscopy. Further clarification of the presence of elemental sulfur is provided by Cryo-XPS. Polysulfide and metal-deficient sulfide could not be detected within this system.

Physical properties of pulse electrodeposited lead sulfide thin films

“…12b and c. The spectrum in the region corresponds to sulfur shows the presence of S in 2 different environments; S 2p3/2 at 160.4 eV is due to the sulfur in sulfide (i.e. PbS), which is in accordance with the literature (160.720 eV and 160.4 eV) [43]. The peak at the higher B.E 161.64 eV can be assigned to Pb-S-O.…”

Treatment of strongly acidic wastewater with high arsenic concentrations by ferrous sulfide (FeS): Inhibitive effects of S(0)-enriched surfaces

“…The precipitates formed in the As(III)-removing system showed the S(2p) binding energy of 162.6 eV, which was assigned to the sulfide ion [S(-II)] [23]. In the As(V)-removing system, the S(2p) binding energy showed a 0.9 eV shift to higher energy at 163.2 eV, and indicated the existence of elemental sulfur [S(0)] at higher binding energy [24].…”

Effects of salinity on xanthate adsorption on sphalerite and bubble–sphalerite interactions

“…4c, two doublets are fitted at 161.5 eV and 162.8 eV. The first doublet corresponds to zinc sulfide (Hampton et al, 2011;Teng et al, 2012). The second doublet with a larger full-width at half-maximum (FWHM) is fallen into the binding energy region from 161.8 to 163.8 eV (Buckley and Woods, 1990;Ikumapayi et al, 2012;Khmeleva et al, 2006;Ranta et al, 1981;Szargan et al, 1992) for adsorbed collector species (chemisorbed xanthate, metal-xanthate or dixanthogen).…”