The role of surface sulfur species in the inhibition of pyrrhotite dissolution in acid conditions

Interaction of H2S with α-Fe2O3(0001) surface

“…The binding energy (BE) of S 2p photoelectrons was 161.9 eV. Reported BE's of S 2p 3/2 are 160.9-161.3 eV [14][15][16] [15,[21][22][23][24]. The presence of S 2À at the initial interaction of H 2 S with a-Fe 2 O 3 is consistent with previous findings from FT-IR measurements [4].…”

“…Concurrently, interface Fe ions have been re-oxidized to 3+. The S 2p binding energy for the oxidized surface is close to that of sulfate, SO 4 2À (168.8 eV) [15,[21][22][23][24]. The S 2p XPS spectra with BE 168.8 eV have been reported for pyrite surfaces exposed to O 2 or H 2 O [18,19,29].…”

Hard X-ray photoelectron and X-ray absorption spectroscopy characterization of oxidized surfaces of iron sulfides

“…The chemical reactivity of iron sulfides in the environment and during mineral processing, as well as their electronic and optical properties strongly depend on the composition and structure of the real surfaces formed in natural and technological environ-ments. It is known from X-ray photoelectron spectroscopy (XPS) and other surface-sensitive techniques [2][3][4][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] that iron can be easily released from the lattice of these compounds, leaving non-equilibrium metal-deficient surface layers. The resulting surface sulfur enrichment is generally modest for oxidation-resistant pyrite, with intrinsic (fractured) pyrite surfaces possibly even being S-deficient [2][3][4][5][6][17][18][19][20][21][22][23][24][25][26].…”

“…The resulting surface sulfur enrichment is generally modest for oxidation-resistant pyrite, with intrinsic (fractured) pyrite surfaces possibly even being S-deficient [2][3][4][5][6][17][18][19][20][21][22][23][24][25][26]. In contrast, the metal depleted layer incorporates di-and polysulfide species and low-spin Fe(II) and can be as thick as several micrometers at pyrrhotite reacted in acidic solutions under certain conditions [27][28][29][30][31][32][33][34][35]; for example, Pratt and co-workers [30][31][32] have reported Auger depth profiles of several reacted pyrrhotites. It remains, however, unclear how the undersurface species alter with depth, in particular, because Ar + ion sputtering employed in many works could seriously affect the chemical state of Fe and S.…”

Semi-Coke–Supported Mixed Metal Oxides for Hydrogen Sulfide Removal at High Temperatures

“…As shown in Table 3, in the fresh sorbent, Mn 2p 3/2 has a binding energy of 642.3-642.5 eV, which corresponds to Mn 4 + (Al-Sagheer and Zaki, 2000), as indicated by the existence of ZnMnO 3 in XRD. The Fe 2p 3/2 peak with a binding energy of 711-712 eV corresponds to an Fe(III)-O environment according to Thomas et al (1998). In the sulfided ZFM0.6/MS, Mn 2p 3/2 has a binding energy of 641.6 eV, which accounts for Mn 3 + (Al-Sagheer and Zaki, 2000).…”