| To produce Calcium absorbent for flue gas desulfurization with the high specific surface area, fly ash was reacted with Ca(OH)2 at elevated temperature in slurry, the increase of the specific surface area of Calcium absorbent benefit the desulfurization efficiency and the utilization of Ca(OH)2. Through reading large number of literature the research find that the humidity content had positive correlation to the activity of Calcium absorbent. Calcium absorbent with more humidity content had the more activity, and the humidity content enlarged with the specific surface area. CaSO4·2H2O /Ca(OH)2 ratio,hydration temperature,hydration time,fly ash/Ca(OH)2 ratio,fly ash species and skived or not, they were the six most significant factors effect on the specific surface area of absorbent. The optimal factors were: the CaSO4·2H2O /Ca(OH)2 ratio is 1.5/1, hydration temperature is 90℃, hydration time is 12 hour, fly ash/Ca(OH)2 ratio is 3/1, fly ash Jia and skived fly ash. The other little significant factors took out each optimal level through its impact trend and economic considerations. The modified Jander Equation could describe the reaction of fly ash reacted with Ca(OH)2 at elevated temperature approximately, and the apparent reaction velocity constant and the order of reaction decided the process of reaction together. The adding of CaSO4·2H2O could increase the velocity of reaction and the rate of conversion of active matter in fly ash. The enlarged experiment verified the conclusion obtained from the original experiment. Scanning electron microscope (SEM) showed the variation of particles before and after the reaction.
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