Influence of combustion temperature and coal types on alumina crystal phase formation of high-alumina coal ash
| Autor: | Man Zhang, Shahong Zhu, Hairui Yang, Zirong Li, Junfu Lyu, Yang Zhang, Junmin Sun |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Pulverized coal-fired boiler business.industry Mechanical Engineering General Chemical Engineering Metallurgy technology industry and agriculture respiratory system engineering.material equipment and supplies Combustion complex mixtures Bauxite Fly ash otorhinolaryngologic diseases engineering Coal Heat of combustion Fluidized bed combustion Physical and Theoretical Chemistry business Refining (metallurgy) |
| Zdroj: | Proceedings of the Combustion Institute. 37:2919-2926 |
| ISSN: | 1540-7489 |
| DOI: | 10.1016/j.proci.2018.06.123 |
| Popis: | The alumina content (more than 40%) of high-alumina coal ash is comparative to the middle content bauxite ores in China. So far, in order to meet the high demand of alumina and the rise of circular economy industrial chain, extracting alumina from coal ash has become a way to comprehensively utilize high-alumina coal ash. However, this process has high requirements on the crystal phase and stability of alumina. Different from most studies, this paper focuses on how to produce coal ash more beneficial to the later refining of aluminum. Therefore, the effects of combustion temperature and coal types by classifying high-alumina coal into dull coal and bright coal on alumina crystal phase formation were studied. Through proximate analysis, ultimate analysis, calorific value analysis, X-ray fluorescence spectroscopy, X-ray diffraction (XRD) and scanning electron microscope (SEM) and other methods, it is found that γ-Al2O3 in high-alumina coal ash translated into more stable θ-Al2O3 and finally α-Al2O3 when combustion temperature is higher than 1000°C. Thus compared with pulverized coal boilers, circulating fluidized bed (CFB) boilers with lower combustion temperature can produce higher quality coal ash. Moreover, at the same combustion temperature, alumina crystal phase in dull coal ash is relatively less stable than that in bright coal ash, which is more suitable to the later refining and electrolysis of aluminum. |
| Databáze: | OpenAIRE |
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