HYDROTHERMAL SYNTHESIS OF ZEOLITES IN NAO H SOLUTION FROM HADONG KAOLIN OF KOREA - IN CASE OF STARTING MATERIALS OF KAOLIN WITH ADDITION OFSILICA

The hydrothermal synthesis of zeolite from Hadong Kaolin(SiO2/Al2O3 mo le ratio=2.54) with addition of amorphous silica has been studied. The experiment was carried out inconditions, by using stainless steel aut oclaves of 24 mL with stirred system at 175 degrees C. Reaction time, SiO2/Al2O3 mole ratio, and water content were changed. For the convent ional synthesis of ZSM-5 zeolite, the particular organic reagent such as TPAOH (tetrapropylammonium hydroxide) has been added as soil humic substances. The conditions of zeolite synthesis and effectiveness of H adong Kaolin without addition to any organic reagent as template were investigated, because Hadong Kaolin is supposed to contain such organi c compound. The results were summarized as follows. 1) When Hadong Kao lin was used as a raw materials for the synthesis of ZSM-5, no organic reagent was necessary. 2) The obtained zeolites mere ZSM-5, mordenite , and analcite respectively. 3) For the transformation to ZSM-5) and m ordenite from amorphous material, the formation of zeolite in 98% wate r content was more rapid than those of 95%. But in the formation of an alcite the result was opposite. 4) For the dissolution of solids by Na OH, the quantity of SiO2 and Al2O3 in liquid varied until ZSM-5 was sy nthesized. But, SiO2 was almost constant and Al2O3 increased in the fo rmation range of ZSM-5.