Patent ID: 6638342
Filing Date: 2003-10-28
Classification: B01D,C01C,C05C,C05G

Abstract:
A flue gas scrubbing process in which a flue gas containing acidic gases and metals and/or metal compounds is contacted with an ammonium sulfate solution to absorb sulfur dioxide and produce a byproduct containing ammonium sulfate precipitate and dissolved metals and/or metal compounds, the method comprising the steps of:producing an aqueous fertilizer solution containing dissolved ammonium sulfate and dissolved metals and/or metal compounds by adding water to the byproduct; adjusting the pH of the aqueous fertilizer solution with gaseous and/or liquid ammonia to form precipitates of at least one metal specie; removing the precipitates of the metal specie from the aqueous fertilizer solution; adjusting the pH of the aqueous fertilizer solution with gaseous and/or liquid ammonia to form precipitates of at least a second metal specie; removing the precipitates of the second metal specie from the aqueous fertilizer solution; and dewatering at least a portion of the aqueous fertilizer solution to precipitate ammonium sulfate.