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Dissolution Mechanisms of Tetravalent Sulphur in Silicate Melts: Evidences from Sulphur K Edge XANES Studies on Glasses
Author(s) -
Backnaes Linda,
Stelling Jan,
Behrens Harald,
Goettlicher Joerg,
Mangold Stefan,
Verheijen Oscar,
Beerkens Ruud G. C.,
Deubener Joachim
Publication year - 2008
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2007.02044.x
Subject(s) - xanes , sulfur , solubility , sulfide , silicate , chemistry , dissolution , polysulfide , inorganic chemistry , electron microprobe , analytical chemistry (journal) , mineralogy , spectroscopy , electrolyte , physics , organic chemistry , electrode , quantum mechanics , chromatography
Incorporation of sulphur in silicate glasses produced by reactions between melts and sulphur‐bearing sources at high temperatures was studied by X‐ray absorption near edge structure (XANES) spectroscopy at the sulphur K edge. Three types of syntheses were performed using sodium trisilicate, soda lime silicate, and float glass as starting materials: (i) controlled bubbling of glass melts with SO 2 or SO 2 /O 2 gas mixtures at ambient pressure, (ii) melting of glass powder containing various salts (Na 2 SO 4 , Na 2 SO 3 , Na 2 S) in excess to the expected solubility in the melt and (iii) fusion of glass powder in gold capsules at 1000°C and 100 MPa with an added amount of salts below the expected sulphur solubility. In some of the latter experiments water was introduced to vary the oxygen fugacity in the system. Sulphur concentrations in the glasses were determined by combustion and subsequent IR spectroscopy; water concentration in the glasses was measured by IR microspectroscopy. Bulk composition and homogeneity of glasses were checked by electron microprobe analyses. XANES spectra obtained at room temperature give evidence for incorporation of sulfate (S 6+ ) and/or sulfide (monosulfide [S 2− ] and/or polysulfide [S x 2− ]) in all glasses, depending on starting materials and run conditions. Clear evidence for sulfite (S 4+ ) was not found in any of the spectra, implying that this sulphur species in glass products at room temperature is at or below the detection limit. We suggest that tetravalent sulphur (as SO 2 or Na 2 SO 3 ) disproportionates into sulfate and sulfide when being dissolved in simple silicate melts or during cooling of the glass melt.