Preparation of Zeolite A Tubes from Amorphous Aluminosilicate Extrudates

A method is presented for the hydrothermal synthesis of binderless zeolite A bars and tubes with high purity from amorphous aluminosilicate extrudates. The solid that was separated from a hydrogel was mixed with an aqueous solution of hydroxyethyl cellulose to obtain a paste, which was extruded into bars and tubes. After calcination, amorphous bars and tubes were converted to zeolite A in the liquid phase that was separated from the hydrogel. The zeolite bars and tubes were composed of cubic zeolite A crystals and had only macropores with an average pore size of ~3 (mu)m besides the zeolite pores. Zeolite A bars exhibited moderate mechanical strength, with a crush strength of 0.4 MPa.