In situ mössbauer study of iron sulfides interactions with coal and model compounds

Abstract The iron sulfides play the most important role in coal liquefaction of all the iron-bearing minerals. The presence of pyrite in a coal tends to enhance the production of lower viscosity liquids. Detailed knowledge about the decomposition of pyrite, the effect of hydrogen and hydrogen sulfide and the type of solvent used is necessary to understand all the factors controlling the rate of decomposition and the type of products formed during coal liquefaction. A series of model compounds was selected to study the catalytic behavior of iron sulfides (FeS 2 Fe 7 S 8 ) at temperatures comparable to those used in direct coal liquefaction. The measurements were carried out in an inert as well as in a hydrogen atmosphere. There was strong evidence of interaction of the iron sulfides with a number of model compounds. The results are discussed in light of the potential catalytic role of iron sulfides in coal liquefaction.