Regeneration of ferric ions in coal desulfurization process

Abstract

A process for removing sulfur from coal using a ferric solution wherein iron loss by precipitation of insoluble iron compounds is controlled by regulation of the hydrogen ion concentration of the reaction slurry. The pH or other measurable condition at which the process is at least self-sustaining with respect to ferric ions is determined for a particular coal sample. The reaction slurry is monitored for changes in the chosen condition which signal a loss of iron from solution, and acid is automatically added as needed to prevent iron precipitation or to return precipitated iron to solution.

Dependencies are inferred from the claim text.