科研之友
微信
新浪微博
Facebook
分享链接
摘要
The dehydration behaviors of FGD gypsums from three power plants were investigated at N(2) atmosphere (autogenous and negligible partial pressure of water, P(H2o)) in non-isothermal and isothermal condition. The dehydration of gypsum proceeded through one step, i.e., CaSO(4)center dot 2H(2)O -> gamma-CaSO(4) (gamma-anhydrite) or two steps, i.e., CaSO(4)center dot 2H(2)O -> CaSO(4)center dot 0.5H(2)O (hemihydrate) -> gamma-CaSO(4) depending on temperature and P(H2O.) The discrepancies of three FGD gypsums on dehydration behavior were very likely due to the different crystalline characteristics (size and habit) and impurities, such as fly ash and limestone. Experimental data of non-isothermal analysis have been fitted with two 'model-free' kinetic methods and those of isothermal analysis have been fitted with Avrami and linear equation. The apparent empirical activation energies (E (a)) suggest that the transition from gypsum to hemihydrate is mainly controlled by nucleation and growth mechanism, while the transition from gypsum to gamma-anhydrite is mostly followed by phase boundary mechanism.
- 出版日期2011-5
- 单位宁波工程学院; 浙江大学
