INCORPORATION OF SULFUR IN COAL PRECURSOR

In order to increase understanding of the incorporation of sulfur in coal precursor, five samples from humic acid extracted from lignite were prepared by treatment with powdered sulfur, precipitated sulfur and H2S. In addition, iron-humic acid complex was formed by reaction of humic acid with iron(II) and was treated with H2S. It was found that bisulfide (SH-) is the important sulfur species incorporated into the humic acid system, resulting in iron bonded to -SH and to disulfide linkages. Incorporation of sulfur resulted in increased stability of the coal precursor to thermal treatment. It is inferred that sulfur distribution in coal is dependent on iron distribution.