High-temperature oxidation of bismuth- and antimony-based sulfosalts

ABSTRACTIn this article, oxidation processes of Ag-Bi-Sb-based phases were investigated. Synthesized AgBiS2 and AgSbS2-Sb2S3-Sb samples were thermally analyzed in synthetic air by applying the simultaneous DSC-TGA analysis technique. The oxidation processes at PO₂=0.2 atm and T<1173 K were observed to take place in many-step sequence of various reactions with an overall reaction 2AgMeS2 + 5.5O2(g) ⇄ 2Ag + Me2O3 + 4SO2(g), where Me=(Bi,Sb). Oxidations of AgBiS2, Sb2S3, and AgSbS2 were observed to begin above 549±2K, 610±2K, and 733±2K, respectively. Furthermore, oxidation processes of AgBi3S5 and Ag3SbS3 were estimated, and thermodynamic functions for the overall oxidation reactions were calculated and discussed.