High-Temperature Oxidation of Bismuth- and Antimony-Based Sulfosalts

ABSTRACT

In 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 P_O₂=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.

KEYWORDS:

• Thermal oxidation
• DSC-TGA analysis
• Pyrometallurgical roasting
• Gibbs energy

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Additional information

Funding

The authors are grateful to the Academy of Finland and the Johan Gadolin Scholarship Programme for financial support. This work was made under project “Thermodynamic investigation of complex inorganic material systems for improved renewable energy and metals production processes” as part of the activities of the Johan Gadolin Process Chemistry Centre at Åbo Akademi University. Part of this work was made as a sub task of Improved Sulfide Smelting (ISS) project of Fimecc Oy, supported also by Boliden Harjavalta, Boliden Kokkola Oy, Norilsk Nickel Finland Oy and Outotec (Finland) Oy.