PREPARATION OF ZEOLITE STABLE TO WATER AND HEAT

PURPOSE:To obtain the faujasite type zeolite having improved stability to water and heat, by treating the faujasite type zeolite containing an alkali (earth) metal with a strongly acidic cation exchange resin and aqueous ammonia, and calcining the treated faujasite type zeolite. CONSTITUTION:(a) An aqueous slurry of the faujasite type zeolite containing an alkali metal or alkaline earth metal is treated with a strongly acidic cation exchange resin to remove 30-70% alkali (earth) metal contained in the zeolite. (b) The resultant zeolite is then brought into contact with aqueous ammonia for 0.5-15hr and calcined at 500-800 deg.C for 2-8hr. (c) The calcined zeolite is further made into an aqueous slurry, and treated with the strongly acidic cation exchange resin to reduce the amount of the alkali (earth) metal contained in the zeolite to 2wt% or less expressed in terms of the oxide. (d) The resultant zeolite is further brought into contact with the aqueous ammonia for 0.1-20hr and calcined at 500-800 deg.C for 1.5-8hr to give the aimed zeolite.