The Research on Crystal Morphology and Size Distribution of Gypsum Crystallization With Metallic Ions in WFGD

The desulfurization gypsum quality is one of the bottleneck of restricting wet limestone gypsum desulfurization technology. Through this study,the results could be analysised by scanning electron microscope( SEM) and concluded that the crystal form of gypsum could be changed and lowed the de-water-ability of gypsum with the addition of metallic ions,for example Fe3+,Mg2+,Al3+. The better crystal shape and the higher of temperature which gypsum crystallization were generated. And in the same concentration of metallic ions,the impact of iron was greater than the impact of magnesium ions. The columnar trapezoid body of gypsum crystal was turned to be needle shape which is difficult to dehydration. And the average size distribution of gypsum crystal with ferric ions D50 is the biggest,but the D50 of Fe3 +/Mg2 +/Al3 +mixture ions is the minimum. The result show that the influence of temperature on gypsum crystal particle size is that low temperature is not conducive to the formation of crystals,but high temperature does not favor to the crystal grain size grew up.