Characterization of Elemental Transport from Fly Ash: A Column Study

The development of sustainable management practices for coal fly ash requires the understanding of the release of toxic elements from fly ash into the environment. Reactive mass transfer modeling implemented by AQUASIM was able to adequately describe the release and transport of magnesium and cadmium from fly ash. However, the adsorptive interactions between arsenic and carbon residues in fly ash complicated the modeling of the retardation of arsenic transport in fly ash. Selenium was another toxic element that exhibited strong retardation in the column leaching study due to adsorptive interactions. The results from this study suggest that processes, in addition to reactive mass transfer, need to be included to describe the leaching of elements exhibit strong adsorption/desorption characteristics. The modeling approaches reported in this study provide a framework for assessing the release and transport of toxic elements from fly ash during beneficial reuse.