【摘要】 用扫描电子显微镜／能量色散谱(SEM／EDS),超级场发射电子显微镜(Super FE-SEM)研究了H2SO4与粉煤灰的固相反应。常温反应后,单个粉煤灰表面微区有明显的溶解点,粉煤灰在一定程度上出现粘结、结块现象。反应前后粉煤灰的组成变化不大,表明固相反应仅在粉煤灰表面进行,未渗入到颗粒内部。反应后所得水溶物主要是Al2(SO4)3、Fe2(SO4)3。当反应温度达到200℃时,扫描电镜可观察到粉煤灰表面产生块状Al2(SO4)3、Fe2(SO4)3结晶。250℃下反应产生的结晶物明显多于200℃,且导电性明显提高。热力学计算和表面纳米观测技术都表明,粉煤灰表面的铝、铁氧化物转化成可溶性的硫酸盐,氧化硅未参与化学反应。更多还原

【Abstract】 The reaction process of fly ash with H2SO4 at solid state studied by the use of Scanning Electron Microscope with Energy Disperse Spectrum(SEM/EDS) and Super Field Emission-Scanning Electron Microscope (Super FE-SEM) in this paper. At room temperature after blending acids (0.1mL/lg), the fly ash was pasted and some crystalline substances at certain area of particles were formed. There almost had no change in the composition of fly ash. After reaction only element of S had increased a little; the small holes were left on the remainder of fly ash when it was washed by two-de-ionized water, which revealed that the solid state reaction recurred at certain area and with certain substances at the surface of particles. The crystal substances that were crystallized from the solution which was used to wash the reacted fly ash, were found to be alumina salt and iron salt, and the former contains more than the latter. With SEM/EDS the flower crystal substance was found on the fly ash also having more iron salt than alumina salt, which showed that iron salt was easier to crystallize at room temperature on the fly ash. Meanwhile, when the dealing temperature was above 200℃,there was square crystalline substance formed at the surface of fly ash, which was alumina salt and iron salt as well, and whose composition was similar to the washed crystal substances. It revealed that high temperature avails crystal of alumina salt on the fly ash, which would help fly ash to deal with waste water.更多还原