论文部分内容阅读
The process of nucleation and crystal growth of NaY zeolite over a temperature rangeof 55°--100℃ in the presence of “crystal direction agent ” are studied. The apparent ac-tivation energy for nucleation and that for crystal growth are evaluated. The mechanism ofthe recrystallization of NaA into NaY is investigated by adding NaA zeolite to the reactionmixture in which the crystallization of NaY zeolite is proceeding. The recrystallization ofNaA zeolite does not occur until the NaY crystallization from the reaction mixture is com-pleted. Thus the process of recrystallization of NaA into NaY might be shown as follows: Amorphous aluminosilicate gel→NaY NaA→NaY NaA Scanning electron microscopic observations and the recrystallization curves show that therecrystallization of NaA into NaY is getting n with a degradation and dissolution of surfacecrystals on the NaA zeolite and that the nucleation and crystal growth of NaY take placeimmediately at the surface of NaA crystals.
The process of nucleation and crystal growth of NaY zeolite over a temperature range of 55 ° -100 ° C in the presence of “crystal direction agent” are studied. The apparent ac-tivation energy for nucleation and that for crystal growth are evaluated. The recrystallization of NaA zeolite does not occur until the NaY crystallization from the reaction mixture is com-pleted. Thus the process of recrystallization of NaA into NaY might BE shown as follows: Amorphous aluminosilicate gel → NaY NaA → NaY NaA Scanning electron microscopic observations and the recrystallization curves show that there crystallization with NaA into NaY is getting with with a degradation and dissolution of surface crystals on the NaA zeolite and that the nucleation and crystal growth of NaY take placemediately at the surface of NaA crystals.