The Effect of the Extraction Fraction of SiO2 and Al2O3 on the Synthesis of Zeolite from Allophanes

Abstract

The dissolution charactristics of several kinds of allophanes with different SiO2/Al2O3 mole ratie (i, e, g) Kiso-do, Terauchi-do, Kitakami-do and Osawa-do in NaOH solution were studied. The effect of SiO2/Al2O3 mole ratio and chemical composition of these allophanes on the synthesis of zeolite was also investigated.
The extraction fraction of alumina in allophane increased with treating time, while the extraction fraction of silica in allophane increased initially and then decreased rapidly.
Due to the low extraction fraction of silica-alumina and small SiO2/Al2O3 mole ratio (2), A-type zeolite was synthesized from Kiso-do and Terauchi-do. The content of the zeolite from Terauchi-do was 100%, Faujasite-type zeolite was synthesized without additional silica in cases of Kitakami-do and Osawa-do which showed higher extraction rates and larger SiO2/Al2O3mole ratio than Kiso-do and Terauchi-do.