| abstract |
Methods, processes, and systems for reducing the solubility of toxic constituents found in coal combustion residues are provided. In one embodiment, methods for adding chemical reagents to the coal combustion process that changes the chemical composition of the coal combustion residues and convert the form of a toxic constituents to one with lower aqueous solubility is provided. In some embodiments compounds containing toxic constituents are converted to compounds that are less soluble in aqueous solvents. In various embodiments, the chemical reactions are aided by the ambient heat at various zones within the coal combustion system. In some embodiments, precursor reagents are added to the coal combustion system and converted to reagents to aid in interacting with toxic constituents or compounds. In various embodiments, the reagent or reagent precursor is added before, during, or after the coal combustion zone. These methods can aid in rendering coal combustion products less hazardous when the products are recycled, stored, or disposed. |