Abstract:

In order to improve the comprehensive utilization of fly ash resources,porous mullite materials were prepared by solid sintering using fly ash as the silicon source,alumina hydroxide as the aluminum source,AlF₃ as the crystal whisker accelerator,and V₂O₅ as the sintering aid.The effects of the ratio of fly ash to aluminum hydroxide (28.2:71.8,34.2:65.8,40.2:59.8,46.2:53.8 and 52.2:47.8,respectively) on the properties,the phase composition and the microstructure of the prepared porous mullite materials were studied.The results show that with the ratio of fly ash to aluminum hydroxide increasing,the apparent porosity gradually increases,the compressive strength and bulk density gradually reduce,the diffraction peaks of mullite gradually strengthen,while those of corundum gradually weaken and disappear;when the mass ratio of fly ash to aluminum hydroxide is 52.2:47.8 the sample shows an apparent porosity of 53.1%,the bulk density of 1.12 g·cm^-3,the compressive strength of 22.8 MPa,and the length to diameter ratio of 30.

Key words: fly ash, aluminum hydroxide, porous ceramics, mullite

摘要：

为了提高粉煤灰的资源化综合利用水平,以粉煤灰为硅源,Al(OH)₃为铝源,AlF₃为晶须促进剂,V₂O₅为烧结助剂,采用固相烧结法制备了莫来石多孔材料,主要研究了粉煤灰与Al(OH)₃的配比(质量比分别为28.2:71.8、34.2:65.8、40.2:59.8、46.2:53.8、52.2:47.8)对制备的莫来石多孔材料性能、物相组成和显微结构的影响。结果表明:1)随着粉煤灰与Al(OH)₃的质量比增大,试样的显气孔率逐渐增大,体积密度和耐压强度逐渐减小。2)随着粉煤灰与Al(OH)₃的质量比增大,试样中莫来石的衍射峰逐渐增强,刚玉衍射峰逐渐减弱直至消失。3)当粉煤灰与Al(OH)₃质量比为52.2:47.8时,试样的显气孔率为53.1%,体积密度为1.12 g·cm^-3,耐压强度为22.8 MPa,莫来石晶体的长径比达到30。

关键词: 粉煤灰, Al(OH)₃, 多孔陶瓷, 莫来石