The action of direct sonication (US) versus conventional hydrothermal method (HY) was investigated to determine the differences in the crystallization mechanism of zeolite formed from fly ash. The results showed that ultrasonic energy is decisive in very fast faujasite and A-type zeolite transformation into more stable sodalite phase. The data display the main presence of sodalite together with a low amount of faujasite and zeolite A after the first 3 hours of sonication. The full transformation of the latter two phases into sodalite takes place after 1 hour more of treatment. The samples incubated by hydrothermal process for 3 hours, instead, are characterized by the main presence of faujasite and A- type zeolites. The progressive synthesis of sodalite at the expense of the other two phases begins only after 4 hours of treatment. The conclusion is that the crystallization of zeolites by ultrasonic and hydrothermal method proceeds via two different mechanisms. The data also show that the two approaches affect the stability of the synthetic products in a different way over the years.

研究了直接超声（US）与常规水热法（HY）的作用，以确定由粉煤灰形成的沸石的结晶机理的差异。结果表明，超声能对快速的八面沸石和A型沸石转变为更稳定的方钠石起决定性作用。数据显示在超声处理的前3小时中，主要存在方钠石以及少量的八面沸石和A型沸石。在经过1小时的处理后，后两个阶段完全转变为方钠石。相反，通过水热过程孵育3小时的样品的特征在于主要存在八面沸石和A型沸石。以其他两个阶段为代价的方钠石的逐步合成仅在处理4小时后才开始。通过两种不同的机制。数据还表明，多年来，这两种方法以不同的方式影响合成产品的稳定性。