微硅粉固相反应制备莫来石粉体工艺

 以微硅粉和工业氧化铝为原料，在空气气氛下固相反应合成莫来石粉体。研究了煅烧温度和Al₂O₃/SiO₂的物质的量比对反应产物物相组成的影响，结果表明，当Al₂O₃ /SiO₂的物质的量比为3：2.5、煅烧温度为1450℃时，制备莫来石粉体质量分数达到最高，根据K值法计算其质量分数为95%。莫来石粉体平均粒径随球磨时间延长而逐渐减小，最终粉体平均粒径为0.58μm，比表面积为9.26m²/g，粒径分布由单峰分布演变为双峰分布，莫来石粉体颗粒形状不规则，以多边体状存在。

Preparing Mullite Powders by Solid-state Reaction Utilizing Waste Silica Fume

The mullite powders are prepared through solid-state reaction of manufactured alumina and silica fume in air atmosphere. The influences of calcination temperature and different Al₂O₃/SiO₂ ratios of the amount of substance on the crystalline phases are discussed. The results show that the powder has the maximum mullite content of 95% by K calculating when the Al₂O₃/SiO₂ ratio of the amount of substance and the calcination temperature are 3:2.5 and 1450℃, respectively. On this basis, the relationship between the mullite powders property and the milling time is investigated using particle size distribution analyzer, BET tester and field emission scanning electron microscopy. The average size of mullite powders diminishes with the milling time, with the diameter distribution evolving from unimodal distribution to bimodal distribution. The average size of as-prepared mullite powders is 0.58μm and its BET value is 9.26m²/g. The as-received mullite powders present an irregular shape of polygon.