Insight into Influence of Glycerol on Preparing α-CaSO4•1/2H2O from Flue Gas Desulfurization Gypsum in Glycerol Water Solutions with Succinic Acid and NaCI

The conversion of CaSO4 center dot 2H(2)O (DH) to CaSO4 center dot 1/2H(2)O (HH) was facilitated by increasing glycerol content from 55% to 85% in glycerol-water mixtures; the average length and diameter of produced alpha-HH crystals decreased from 60.97 to 7.21 mu m and from 15.21 to 5.17 mu m, respectively, resulting in a decrease in the average aspect ratio from 4.06 to 1.41. The phase transformation was reduced dramatically from 30 to 3 h. As glycerol content increased in the mixtures, an increase in alpha-HH maximal relative supersaturation and decrease of ion diffusion rate were hypothesized as explanations for the morphology change in the alpha-hemihydrate (alpha-HH) produced. The kinematic feasibility of FGD gypsum transition to alpha-HH in the mixed solutions with the increase of glycerol should also be attributed to the enhancement of maximal relative supersaturation for alpha-HH precipitation.