ABSTRACT
The removal of organic sulfur from coal with physical separation methods remains a significant challenge. However, organic sulfur may represent up to 50% of the sulfur content of many coals, and thus meeting increasingly demanding sulfur restrictions will end up requiring the removal of this organic sulfur. There are several possible approaches for enabling organic sulfur removal, including solvent partitioning, thermal decomposition, acid–base neutralization, sulfur reduction, sulfur oxidation, and nucleophilic displacement. Additionally, pyritic sulfur can be solubilized and removed in the aqueous phase. There are several issues with chemical processing methods: the cost of reagents, the necessity of multiple reaction steps, and the complexity of the final coal products to name a few. This chapter discusses several chemical leaching processes from laboratory to pilot-plant scale.
