A novel approach was proposed to prepare ZSM-5 zeolite via hydrothermal synthesis by using Al(OH)₃, which was extracted from fly ash by a staged treatment, as an aluminum source. The synthesis parameters and crystal growth of ZSM-5 were optimized. The optimization of crystal growth for ZSM-5 was investigated under the effect of organic steric-hindrance agents. The crystal phase and morphology of the ZSM-5 were characterized by X-ray diffractometry and scanning electron microscopy, and the particle size distribution was measured by laser particle-size analyzer. The crystal growth of ZSM-5 under different hydrothermal conditions obeyed the “S” regulation. According to the analysis, the formation of ZSM-5 crystal occurred via four steps: (1) the formation of amorphous aluminosilicate by the condensation of silicate ions and aluminate ions; (2) the particle growth and aggregation of the amorphous aluminosilicate; (3) crystallization and crystal growth of ZSM-5; (4) Gentle growth after the zeolite crystal reaches a certain size. The addition of organic steric hindrance agents resulted in a decrease in grain size and crystal-particle formation with a narrow size distribution. Single-grain dispersion resulted and the micropore volume, mesopore volume, and specific surface areas were improved by the presence of organic steric agents.

提出了一种利用Al（OH）₃进行水热合成制备ZSM-5分子筛的新方法。通过分步处理从粉煤灰中提取的铝作为铝源。优化了ZSM-5的合成参数和晶体生长。在有机空间阻滞剂的作用下，对ZSM-5晶体生长的优化进行了研究。通过X射线衍射和扫描电子显微镜对ZSM-5的晶相和形貌进行表征，并通过激光粒度分析仪测量粒度分布。ZSM-5在不同水热条件下的晶体生长遵循“ S”调节。根据分析，ZSM-5晶体的形成通过四个步骤发生：（1）通过硅酸盐离子和铝酸盐离子的缩合形成无定形硅铝酸盐；（2）无定形硅铝酸盐的颗粒生长和聚集；（3）ZSM-5的结晶和晶体生长；（4）在沸石晶体达到一定尺寸后，温和地生长。有机位阻剂的加入导致晶粒尺寸的减小和具有窄尺寸分布的晶体颗粒的形成。结果是单颗粒分散，并且通过有机位阻剂的存在改善了微孔体积，中孔体积和比表面积。