Patent ID: 7524473

Claim:
A method for controlling an amount of mercury discharged to an environment in a flue gas generated by combustion of a fuel source, said method comprising: subjecting said flue gas to a wet scrubbing operation to decrease an amount of sulfur oxides present in said flue gas, said wet scrubbing operation comprising contacting said flue gas with an aqueous alkaline slurry to absorb said sulfur oxides from said flue gas, wherein at least a portion of gaseous ionic mercury species present in said flue gas are dissolved in said aqueous alkaline slurry and thereby removed from the flue gas; measuring a redox potential of the aqueous alkaline slurry used in the wet scrubbing operation to provide a signal indicative of the measured redox potential; and controlling the amount of ionic mercury present in flue gas that can be reduced to elemental mercury by the slurry by adjusting the redox potential of the aqueous alkaline slurry used in the wet scrubbing operation in response to the signal.