电厂煤飞灰颗粒物的物理化学特征

对某台300MW燃煤电站锅炉电除尘器前后的飞灰进行取样，使用激光粒度仪测定粒度分布，使用X射线衍射仪(XRD)和扫描电镜(SEM)研究颗粒中的矿物成分及其微观形貌特征，同时使用电子探针对电除尘器后飞灰的单颗粒进行成分分析．结果表明：通过电除尘装置排入大气的颗粒物平均粒径为2．5μm左右；飞灰粗颗粒中有较多硅铝氧化物和粘土矿物，而细颗粒中则含有较多金属氧化物，且粗颗粒中石英所占矿物相比例相当高；电除尘器前的飞灰形貌类型种类较多，电除尘器后飞灰形貌类型简单，主要是圆球或圆形的颗粒；电除尘器后飞灰单个颗粒间组分随粒径变化的有Si、Al、Ca和S，而元素Fe和Ti的含量较恒定．

Physicochemical Characteristics of Fly Ash from Coal-Fired Power Station

Fly ashes before and after the electrostatic precipitators were sampled. The particle size distribution of the as-received ashes was determined. Crystalline phases presented in the coal, coal ash and slag were analyzed by X-ray diffraction. The morphological observation of samples were performed by scanning electron microscopy. The composition of individual particle was assessed from electron probe microanalyser. The results indicate that the emission of particulate matter from commercial coal combustion source may represent a risk of inhalation into respiratory system. There are more aluminosilicate and clay minerals in coarse particles but more metal-oxide in fine particles. The great majority of the fine particles are spherical.It is shown that the content of Si,Al decreases while that of Ca,S increases with the decreasing of particle size; there are no appreciable differences in the content of Fe, Ti before and after the electrostatic precipitatiors.