Solubility and Fractionation of Different Metals in Fly Ash of Powder River Basin Coal

摘要

Coal is one of the major sources of fuel for electricity production and will continue to be used for many more decades. Thus, it is important to study the effects of disposal of coal burning byproducts including fly ash into the environment. In this study, the solubility of cations and anions from the fly ash in water is discussed. Also, the fractionation of different metals from fly ash in water is studied to understand which fraction of the metals would likely be mobi lized. The results from these studies suggested that the metals in the fly ash are bound mostly to carbonate, organic, and residual fractions. Also, when water solubility data are modeled with a geochemical model (Visual MINTEQ), the saturation index predictions suggested that brucite (Mg(OH)_2) and calcite (CaCO_3) could potentially precipitate and mineralize the atmospheric CO_2. Such mineralization process could potentially reduce the leaching of toxic metals from fly ash. Results from this study will be helpful in understanding the fate of different metals from fly ash land disposal environments.