The coal fly ash was treated hydrothermally at 373K with mixture of NaOH and NaC1 aqueous solution by the microwave heating and the conventional heating. Through this experiment, we investigated effects of additive NaC1 on the crystalline phase and the generation rate of zeolites.
As a result, it was found that phillipsite can be selectively acquired from fly ash by hydrothermal treatment with the mixed solution of 0.4 N NaOH and 1.6 N NaC1 aqueous solution. It was also clarified that both hydroxysodalite and phillipsite are synthesized when fly ash is treated hydrothermally with high concentration NaOH solution and NaC1 solution by the microwave heating.
On the other hand, concerning the generation rate, the synthesis of phillipsite with mixture of NaOH and NaC1 aqueous solution need the longer treatment time than that with NaOH solution. Because the dissolution rate of Al source from fly ash induces the generation rate of the precursor, the aluminosilicate gel. Furthermore, we revealed that the microwave heating reduces the necessary treatment time in the case of the hydrothermal treatment with mixture of NaOH and NaC1 aqueous solution since the microwave heating promotes the crystallization of phhilipste.

ソルト・サイエンス研究財団一般公募助成研究
研究期間: 2006年度
助成番号: 0613