高温处理粉煤灰的理化特性研究

Physical properties and chemical composition of fly ash treated at high temperatures

为多元化、高附加值利用粉煤灰,以朔州电厂粉煤灰为例,进行了X射线衍射测试、粒度测试和热重分析。结果表明,朔州电厂粉煤灰的w(Al2O3)=41. 09%、w(CaO)=4. 64%,属于高铝低钙型,其平均粒径为108. 1μm;未煅烧的朔州电厂粉煤灰矿物组成为莫来石、石英、石膏;质量损失主要发生在570~750℃和1 100~1 280℃。然后称取未筛选经105℃烘干后的粉煤灰制成Φ40 mm×8. 8 mm的试样,经1 200~1 550℃热处理后,进行劈裂强度试验、XRD分析等。结果表明,随热处理温度升高,试样的强度和密度增大,莫来石含量逐渐增多,1 400℃时性能达到最佳。

In order to use fly ash with diversification and high added value,the X-ray diffraction test,particle size test and thermogravimetric analysis were carried out on the fly ash from Shuozhou Power Plant.The results show that the fly ash from Shuozhou Power Plant with Al2O3=41.09 mass%and CaO=4.64 mass%belongs to high alumina and low calcia type,and its average particle size is 108.1μm;before calcination,its mineral phases are mainly composed of mullite,quartz and gypsum.The mass loss mainly occurs at 570-750℃and 1100-1280℃.The fly ash dried at 105℃without screening was used to prepare specimens with dimensions ofΦ40 mm×8.8 mm.The specimens were hot treated at 1200-1550℃,and analyzed with XRD,the cleavage strength was determined.The results show that with the temperature rising,the strength and the density of the specimens increase,and the mullite content increases gradually;at 1400℃,the properties of the specimens are the best.