Abstract: Preparation of calcium sulfate whisker used the raw material of FGD gypsum , which was on mechanical activation , through cooling recrystallization was studied .The effect of mechanical activation on the nucleation and growth of whiskers was discussed , which depended on SEM , image granularity analysis method and related software .The results shows that calcium sulfate whiskers with larger aspect ratio could be prepared by mechanical activation of FGD gypsum .The reaction temperature is 75 ℃, sulfuric acid concentration is 2.5 mol/L, mechanical activation time is 3.5 h.Moreover, in the condition of the slurry concentration of 2;, the average aspect ratio of the prepared calcium sulfate whisker is 150 and the average diameter is 2.1 μm.

Key words: Preparation of calcium sulfate whisker used the raw material of FGD gypsum , which was on mechanical activation , through cooling recrystallization was studied .The effect of mechanical activation on the nucleation and growth of whiskers was discussed , which depended on SEM , image granularity analysis method and related software .The results shows that calcium sulfate whiskers with larger aspect ratio could be prepared by mechanical activation of FGD gypsum .The reaction temperature is 75 ℃, sulfuric acid concentration is 2.5 mol/L, mechanical activation time is 3.5 h.Moreover, in the condition of the slurry concentration of 2;, the average aspect ratio of the prepared calcium sulfate whisker is 150 and the average diameter is 2.1 μm.