Abstract
Allophane was converted into type-A zeolite by the treatment with NaOH aqueous solutions of the concentrations of 1-5 N. The+ conversion process was analyzed by the measurements of the adsorption of NH+4, PO3-4 and methylene blue to the products separated in the course the treatment. The conversion process can be divided into five successive reaction steps;(1) dissolution of alumina-rich surface, (2) development of a new surface, (3) formation of zeolite precursor, (4) formation of type-A zeolite and (5) conversion of type-A zeolite to hydroxysodalite.
