Claims
- 1. A method for producing a synthetic zeolitic molecular sieve having the molar formula:
- 1.25.+-.0.25Na.sub.2 O:1.00Al.sub.2 O.sub.3 :2.10-2.90SiO.sub.2 :1-4H.sub.2 O
- wherein from 5 to 40% of the SiO.sub.2 by weight is nonzeolitic silicate, said method comprising: (a) forming a reaction mixture by mixing sodium hydroxide and sodium silicate in the presence of water and heating for at least 5 minutes, said mixture having a molar ratio of Na.sub.2 O/SiO.sub.2 in the range of 0.6 to 2.5, adding to said heated mixture
- (b) additional sodium silicate such that the resulting mixture has a Na.sub.2 /SiO.sub.2 molar ratio of 0.7 to 1.5 and
- (c) at least one source of solid hydrated amorphous alumina or solid hydrated crystalline alumina in amount such that the SiO.sub.2 /Al.sub.2 O.sub.3 ratio of the mixture is in the range of 2.0 to 4.5, and maintaining the mixture at elevated temperature until crystals of silica enriched zeolitic molecular sieve are formed.
- 2. The method of claim 1, wherein said solid alumina is at least one of gibbsite, bayerite, boehmite and pseudoboehmite.
- 3. The method of claim 1, wherein gibbsite is the predominating source of solid alumina and said gibbsite is digested in a sodium hydroxide solution before adding said gibbsite in step (c).
- 4. The method of claim 3, wherein said gibbsite is ground to a size of 4 to below 20 micrometers before mixing it with sodium hydroxide solution and the ratio of Na.sub.2 O to Al.sub.2 O.sub.3 is in the range of 1.0 to 3.0.
- 5. The method of claim 3, wherein the sodium silicate added in steps (a) and (b) has a SiO.sub.2 /Na.sub.2 O molar ratio of about 3.4/1.
- 6. The method of claim 3, wherein seeds comprising a portion of reaction mixture from a previous interrupted synthesis are added to said heated mixture along with hydrated alumina and additional sodium silicate.
- 7. The method of claim 3, wherein seeds comprising solid product from a previous synthesis are added.
- 8. The method of claim 1, wherein said alumina consists of hydrated amorphous alumina.
- 9. Particles of a crystalline zeolitic molecular sieve composition having the x-ray pattern of type B zeolite and containing from 5 to 40% by weight of the silicate present as non-zeolitic silica in addition to the SiO.sub.2 in the framework of type B zeolite crystals, said particles having a GE brightness of at least 90%.
RELATED APPLICATIONS
This is a continuation-in-part of U.S. Ser. No. 09/030,418, filed Feb. 25, 1998 (pending), which in turn is a continuation-in-part of U.S. Ser. No. 08/891,039, filed Jul. 10, 1997, now abandoned, which in turn is a continuation-in-part of U.S. Ser. No. 08/824,597, filed Mar. 26, 1997, now abandoned.
US Referenced Citations (11)
Foreign Referenced Citations (2)
Number |
Date |
Country |
384070 |
Aug 1980 |
EPX |
1473201 |
May 1977 |
GBX |
Non-Patent Literature Citations (3)
Entry |
H. van Bekkum, et al., "Introduction to Zeolite Science and Practice" Elsevier Science Publishers, (vol. 58) 1991 pp. 94-97. (No month). |
Carr, S.W., Gore, B. and Anderson, M.W., Chem Mater. 1997, vol. 9, pp. 1927-1932. (No month). |
High Resolution Solid State NMR of Silicates and Zeolites, G. Engelhardt and D. Michel, John Wiley & Sons, Chichester, 1987, p. 221. (No month). |
Continuation in Parts (3)
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Number |
Date |
Country |
Parent |
030418 |
Feb 1998 |
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Parent |
891039 |
Jul 1997 |
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Parent |
824597 |
Mar 1997 |
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