Removal of elements from coal fly ash

摘要

A method for removing elements, including heavy metals, from fly ash and from fly ash resulting from removal of SO_x/NO_x from flue gas using Na₂CO₃/NaHCO₃/trona, is described. An aqueous suspension of the fly ash and/or a solution of the leachate from the fly ash is treated with dissolved ferrous compounds, such as FeSO₄.7H₂O and/or FeCl₂.4H₂O, at a chosen initial acidic pH, and the precipitation of the ferrous ions as the solution basifies sequesters the trace elements.