工艺条件对高铝粉煤灰制备莫来石性能的影响

Influence of Technological Conditions on the Property of Mullite Prepared from High-aluminum Fly Ash

以内蒙古中西部地区某电厂煤粉炉高铝粉煤灰为原料,经碱液预脱硅、酸洗除杂活化处理,烧结得到莫来石。研究了不同工艺条件对烧结莫来石产品性能的影响及不同烧结条件下的莫来石产品物相及显微形貌转变规律。实验结果表明,经过预处理后,粉煤灰中的Al2O3含量由47.58wt%提高至65.35wt%,当原料平均粒径为2.89μm,烧结温度为1600℃,恒温时间为2 h时,经预处理后的粉煤灰烧结得到莫来石相含量高、长约10μm左右的棒状晶体,且理化性能良好,满足相关行业标准要求。

High performance mullite ceramics were prepared from high-aluminum fly ash as the only one material. The original fly ash was pretreated with alkali, acid solution and then sintered. Effect of various technological conditions on the properties of sintered mullite was systematically investigated. Furthermore, the phase transformation and morphology evolution of the pretreated fly ash sintered at different temperatures were also studied. The results showed that by pretreated process, A1203 content can increase from 47.58wt% to 65.35wt%. High mullite content and anisotropic grains with 10 μm in length were formed when the powder, 2.89 μm in average diameter, was sintered at 1600 ℃ for 2 h. The beneficiated sintered sample exhibited excellent performance, which can agree with the national standard for the sintered mullite.