科研之友
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摘要
Crystal and phase transitions of a Chinese Datong coal ash were evaluated using room temperature X-ray diffraction (RT-XRD), in-situ high temperature (HT)-XRD, and scanning electron microscope combining energy dispersive X-ray analysis (SEM-EDX) as temperature varied from 300 degrees C to 1600 degrees C. The transforming behaviors of ash were related to its melting properties. Results revealed that the transforming behavior of minerals from in-situ HT-XRD was different with that from routine RT-XRD. Low-temperature Datong ash contained quartz and clays (such as kaolinite); the changes in minerals at low-temperature region (300-1000 degrees C) were mainly due to the minerals decomposition and partial phase transition. Significant transition of quartz to cristobalite occurred at ca. 1100 degrees C; the continuous transition and reaction of silica and alumina at ca. 1200 degrees C accelerated the softening of the ash (ST approximate to 1290 degrees C). An X-ray amorphous liquid phase was formed mainly by the eutectic solution of silica and mullite at ca. 1400 degrees C, which obviously affected the hemisphere temperature (HT approximate to 1490 degrees C) of ash; meanwhile, ultra fine alumina solid particles, which were probably derived from kaolinite, were found in the melted ash. Virtually, the fusing (FT>1500 degrees C) of Datong ash was considered to be determined by the formation of solid particles and eutectic solution. Eventually, the semi-quantitative evaluation of transformations of ash was successfully obtained through the combined methods.
- 出版日期2015-2
- 单位中国矿业大学（北京）
