粉煤灰物理化学性质对比分析研究

Comparative research on physical and chemical properties of coal ash

采用扫描电镜(SEM)、X射线衍射(XRD)等方法,对神华集团准能公司电厂流化床粉煤灰和煤粉炉粉煤灰的物理化学性质进行对比分析。结果表明,两者的化学组成相似,均以氧化铝和二氧化硅为主;煤粉炉粉煤灰和流化床粉煤灰在粒径分布上相近,粒径为1~40μm的粒子约占75%以上;在形貌特征和物相组成上两者相差较大,与流化床粉煤灰相比,煤粉炉粉煤灰在形貌上含有较多表面致密的球形玻璃相颗粒,在物相组成上主要为莫来石和刚玉。因而,煤粉炉粉煤灰中的氧化铝较流化床粉煤灰中的氧化铝的反应活性差,故从煤粉炉粉煤灰中提取氧化铝的难度更大、工艺条件更苛刻、成本也相应更高。

The physical and chemical properties fly ashes from circulating fluidized bed boiler(CFB)and pulverized coal(PC)furnace in power plant of Shenhua Zhunneng Resources Compenhensive Development Company was comparatively studied by scanning electron microscope(SEM)and X-ray diffraction analysis(XRD)etc..The results showed that CFB fly ash and PC fly ash possessed similar chemical composition,which was mainly composed of A12O3 and SiO2.While the grain size distribution of CFB fly ash and PC fly ash was also similar,the 1~40μm fraction was the highest,which was about above 75%.However,the morphology and mineral composition between CFB fly ash and PC fly ash were quite different.Compared to CFB fly ash,the PC fly ash contained a large number of spherical particles with compact shell,and the mineral was mainly composed of mullite and minerals,which resulted in its low reaction activity of alumina.Thus,the extraction of alumina from PC fly ash got greater difficulty,more stringent technological conditions and higher cost.