Process for producing Y-type zeolite
AssigneeToyo Soda Manufacturing Co., Ltd.
InventorsIsao Miyanohara, Shinichi Hashimoto, Hiroshi Miyazaki
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Abstract
A Y-type zeolite having a SiO.sub.2 /Al.sub.2 O.sub.3 ratio of at least about 4 is produced by the following process. In the first step of the process, an aqueous alkali silicate solution and an aqueous alkali aluminate solution are mixed together in the presence of an alkali in an amount such that the ratio of M.sub.2 O(M: an alkali metal)/Al.sub.2 O.sub.3, present in the mixed solution, is at least about 5 by mole, followed by forming a gel in the mixed solution and, then, separating the gel therefrom. In the second step, the separated gel is incorporated in an aqueous alkali silicate solution or an aqueous alkali silicate-alkali mixed solution to obtain a slurry and, then, a Y-type zeolite crystal is formed in the slurry.
Claims5
A process for producing a Y-type zeolite which consists essentially of the steps of:
- incorporating an aqueous alkali silicate solution with an aqueous alkali aluminate solution in the presence of an alkali in such an amount that the ratio of M.sub.2 O (M:
- an alkali metal) to Al.sub.2 O.sub.3, present in the resulting incorporated solution, is in the range of from about 7 to about 30 by mole and the ratio of SiO.sub.2 to Al.sub.2 O.sub.3, present in the resulting incorporated solution, is in the range of from 2 to 10 by mole, forming a gel having a SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio of from about 2.7 to about 3.0 in the incorporated solution, by maintaining the incorporated solution at a temperature of of from 40.degree. C. to 70.degree. C. for a period of at least 20 minutes, separating the gel from the mother liquor by filtration;
- and then,
- incorporating the separated gel in an aqueous solution of an alkali silicate or a mixture of an alkali silicate and an alkali to obtain a slurry having the following oxide molar ratios:
- M.sub.2 O/SiO.sub.2 :
- 0.25 to 0.50
- SiO.sub.2 /Al.sub.2 O.sub.3 :
- 6 to 20
- H.sub.2 O/M.sub.2 O:
- 20 to 80
- wherein M is an alkali metal, followed by forming Y-type zeolite crystals in the slurry.
Dependencies are inferred from the claim text.