The present study investigates the glassy and crystalline phases of silica content in different fly ash sources by X-ray photoelectron spectroscopy (XPS). The X-ray diffraction (XRD) patterns of fly ash show the existence of crystalline quartz, aluminosilicate, and hematite phases. Other minor phases viz., CaO, TiO₂, and K₂O have also been identified in the fly ash samples. The signature of glassy phase (amorphous content) of silica is identified by a hump over the 2θ range of 20–30° in X-ray diffraction pattern. A detailed study of amorphous and crystalline silica, aluminosilicate, ferric oxide, and calcium oxide is done by XPS. Quantitative analysis of Si 2p spectra of both fly ash samples shows amorphous content of SiO₂ in the range of 10–40 atomic percent. Other phases, namely, mullite (24–65 at.%), alumina (35–75 at.%), and crystalline SiO₂ (60–90 at.%) have also been found in both the fly ash samples.

中文翻译：

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X射线光电子能谱法研究低钙粉煤灰中玻璃相二氧化硅

本研究通过 X 射线光电子能谱 (XPS) 研究了不同粉煤灰源中二氧化硅含量的玻璃相和结晶相。飞灰的 X 射线衍射 (XRD) 图案显示存在结晶石英、铝硅酸盐和赤铁矿相。在飞灰样品中也发现了其他次要相，即 CaO、TiO ₂和 K ₂ O。二氧化硅玻璃相（无定形含量）的特征由 X 射线衍射图中 20-30° 2θ 范围内的隆起识别。XPS 对无定形和结晶二氧化硅、铝硅酸盐、氧化铁和氧化钙进行了详细研究。两种粉煤灰样品的 Si 2p 光谱的定量分析显示 SiO _{2 的}无定形含量在 10-40 原子百分比的范围内。其他相，即莫来石 (24–65 at.%)、氧化铝 (35–75 at.%) 和结晶 SiO ₂ (60–90 at.%) 在这两种飞灰样品中也被发现。