Microwave vs. conventional synthesis of analcime from clear solutions

The synthesis of analcime by microwave and conventional heating was investigated for various conditions. Two clear solution compositions not containing any organic template were used in the experiments. The samples obtained from these compositions were characterized by X-ray diffraction and scanning electron microscopy. Analcime could be prepared at 180 °C from the two different template-free clear reaction mixtures in a relatively short time when microwave heating was utilized. At 120 °C, the use of microwave heating delayed the commonly observed phase transformation of zeolite P into analcime in this study, and pure analcime could not form under the conditions investigated. When conventional heating was used, analcime could be obtained at both 120 and 180 °C. Microwave irradiation generally provided an earlier start of crystal formation and higher zeolite yield, when compared to conventional heating, signifying faster crystallization.