This paper evaluates the effect of using aluminum salts in wet Flue Gas Desulphurization Plants (FGD)
upon mercury reemission. Aluminum sulfate is employed to increase the SO2 retention capacity of low
porosity limestone. However, its presence in the FGD system also influences the chemical reactions of
the species in the scrubber. This study, performed at lab-scale to assess the reduction of mercury from
aqueous solutions and gypsum slurries, has demonstrated that the addition of aluminum sulfate mainly
affects the pH of the solution and the formation of sulfite ions, which in turn affects the mechanisms of
mercury re-emission.