粉煤灰的SEM及X射线能谱微分析研究

Microanalysis of fly ash by SEM and EDS

粉煤灰的微结构和主要成分决定了粉煤灰的物理、化学性能,直接关系到粉煤灰的综合利用。本文利用XRD、SEM及EDS对原灰以及水、磁筛选的粉煤灰进行了物相、表面微结构及X射线微区分析的研究。结果表明:富铁漂珠粒度较其它漂珠小,富铁磁珠表面析出了块状、针状等规则排列的结晶,表面形貌光滑的玻璃微珠主要吸附于中空的漂珠表面和贫铁沉珠中。同时出现一些球形度好、表面光滑的纯铁珠和纯玻璃珠。粉煤灰主要的常量元素为Al、Si、K、Ca、Ti、Fe,它们主要以氧化物的形式存在,富铁漂珠的表面Fe相对含量较其它漂珠和沉珠高,Si主要以玻璃体形式存在,Al元素在燃烧冷却过程中基本实现了相对均匀再分布,Ca、Ti主要以钙钛矿的形式存在。

The physical and chemical performance of fly ash is dependent on its micro-structure and contents. In this work, fly ash was separated by water and magnetic fields, their phase composition and microstructure were investigated by XRD, SEM and EDS. The results showed that rlch-iron floating beads had smaller particle-size than others. Some regular crystals such as block and acicular crystals were deposited on the surface of rich-iron magnetic beads. Some glass micro-pearls with smooth surface were adsorpted on the surface of hollow floating beads and peor-ferro sinking beads. Meanwhile, there were some pure iron beads and pure glass beads with good sphericity and smooth surface. Moreover, the major elements of fly ash were AI, Si, K, Ca, Ti, Fe, existed as its oxides. The relative percentage of Fe on rich-iron floating beads was higher than other floating beads and sinking beads. Si was mainly in glass phase, Al was relatively homogeneously redistributed when they were cooled down, Ca and Ti existed mainly in the perovskite-type oxides.