Process for preparation of synthetic mordenite molded body

An improvement in a process for the preparation of a synthetic mordenite molded body, which comprises molding a starting mixture consisting essentially of as the main components a silica source, an alumina source, an alkali source and water to obtain a starting molded body, calcining the molded body to obtain a calcined molded body and crystallizing the calcined molded body in an aqueous solution of sodium silicate, wherein the improvement comprises (a) making a mordenite seed crystal powder present in the starting mixture, in an amount of 0.1 to 10% by weight based on the starting mixture on a dry basis;

• (b) when the starting molded body is calcined, elevating the temperature by heating to a calcination temperature not lower the 400.degree. C. at an average elevation rate of at least 10.degree. C./min and carrying out the calcination at said calcination temperature within 2 hours;
• and (c) when the calcined molded body is crystallized, using an aqueous solution of sodium silicate having an SiO.sub.2 concentration of 7 to 25% by weight, an Na.sub.2 O concentration of 2 to 8% by weight and an SiO.sub.2 /Na.sub.2 O molar ratio of from 0.9 to 4.0 as the aqueous solution of sodium silicate.