Decomposition of pyrite under coal liquefaction conditions: A kinetic study

• Published in: Fuel (Guildford) Vol. 61; no. 8; pp. 761 - 764
• Main Authors: Thomas, Michael G., Padrick, Thomas D., Stohl, Frances V., Stephens, Howard P.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.1982
• Subjects: coal liquefaction; decomposition reactions; pyrites; decomposition reactions; coal liquefaction; pyrites
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/0016-2361(82)90253-8

The decomposition of FeS 2, both as a single phase and as it exists in coal, has been studied between 250 and 350 °C, in hydrogen and nitrogen atmospheres, and in the presence of a coal-derived solvent. The first-order rate constant for decomposition of FeS 2 at 350 °C with H 2 alone is 6.7 × 10 −1 min −1; with H 2 and coal-derived solvent, it is 5.5 × 10 −2 min −1; for FeS 2 contained within coal, solvent and H 2, it is 8.6 × 10 −3 min −1. Although the rate constant for decomposition is dependent upon temperature and the system, the activation energy in each case has been calculated to be 88 kJ mol −1. A mechanism consistent with these data is the thermal decomposition of FeS 2 to produce Fe 1−xS and S, followed by reaction of the sulphur with available hydrogen (from H 2, solvent or coal) to form H 2S.