Optimizing the characteristics of calcium sulfate dihydrate in the flue gas desulfurization process: Investigation of the impurities in slurry-Cl-, Fe3+, Mn2+

The effects of limestone, Cl-, Fe3+ and Mn2+ in slurry on the characteristics of calcium sulfate dehydrate (DH) in flue gas desulfurization (FGD) process were investigated. The moisture content, particle size distribution, and crystal morphology were considered as end use characteristics of DH. As a result, the number of needle-like DH crystals was increased with increasing total contents of MgCO3, Al2O3 and Fe2O3 in limestone. Cl ions were reported to distort the crystal structure and change the crystals from orthorhombic to irregular. Mn2+ can increase the desulfurization efficiency by catalyzing the oxidation of SO2. Finally, Fe3+ will inhibit crystal growth of all faces, except {011} and {111}.