Claims
- 1. An alkali metal aluminosilicate of the zeolite P type having a silicon to aluminium ratio not greater than 1.33 and having a calcium binding capacity of at least 150 mg CaO per g anhydrous aluminosilicate.
- 2. An alkali metal aluminosilicate as claimed in claim 1, wherein the calcium binding capacity is at least 160 mg CaO per g of anhydrous aluminosilicate.
- 3. An alkali metal aluminosilicate as claimed in claim 1 having a silicon to aluminium ratio within the range of from 0.9 to 1.15.
- 4. An alkali metal aluminosilicate as claimed in claim 1, wherein the calcium binding capacity is at least 160 mg CaO per g of anhydrous aluminosilicate.
- 5. An alkali metal aluminosilicate as claimed in claim 1, having a particle size d.sub.50 within the range of from 0.1 to 5.0 micrometers.
- 6. An alkali metal aluminosilicate as claimed in claim 5, having a particle size d.sub.50 within the range of from 0.1 to 1.0 micrometers.
- 7. An alkali metal aluminosilicate as claimed in claim 6, having a particle size d.sub.90 below 3 micrometers.
- 8. An alkali metal aluminosilicate as claimed in claim 5, having a particle size d.sub.80 below 1 micrometer.
- 9. An alkali metal aluminosilicate as claimed in claim 8, having a particle size d.sub.90 below 3 micrometers.
- 10. An alkali metal aluminosilicate as claimed in claim 8, having a particle size d.sub.80 below 1 micrometer.
- 11. A process for the preparation of an alkali metal aluminosilicate of the zeolite P type having a silicon to aluminium ratio not exceeding 1.33, which comprises the steps of:
- (i) mixing together a sodium aluminate having a mole ratio Na.sub.2 O:Al.sub.2 O.sub.3 within the range of from 1.4 to 2.0 and a sodium silicate having a mole ratio SiO.sub.2 :Na.sub.2 O within the range of from 0.8 to 3.4 with vigorous stirring at a temperature within the range of from 25.degree. to boiling point to give a gel having the following composition:
- Al.sub.2 O.sub.3 : (1.75-3.5) SiO.sub.2 : (2.3-7.5) Na.sub.2 O: (80-450)H.sub.2 O;
- (ii) ageing the gel composition for 0.5 to 10 hours at a temperature within the range of from 70.degree. to boiling point with sufficient stirring to maintain any solids present in suspension;
- (iii) separating the crystalline sodium aluminosilicate thus formed, washing to a pH within the range of from 10 to 12.5, and drying to a moisture content of not less than 5 wt %.
- 12. The process of claim 11 wherein the mixing and ageing steps are carried out at 95.degree. C. and the gel composition is aged for 2-5 hours.
Priority Claims (2)
Number |
Date |
Country |
Kind |
8825783 |
Nov 1988 |
GBX |
|
8910029 |
May 1989 |
GBX |
|
Parent Case Info
This is a continuation of application No. 08/012,807, filed Feb. 2, 1993, now U.S. Pat. No. 5,374,370, which is a continuation of Ser. No. 07/430,988, filed Nov. 3, 1989, now abandoned.
US Referenced Citations (16)
Foreign Referenced Citations (4)
Number |
Date |
Country |
0021491 |
Jan 1981 |
EPX |
0257700 |
Mar 1988 |
EPX |
2620393 |
Nov 1977 |
DEX |
2849898 |
Nov 1978 |
DEX |
Non-Patent Literature Citations (2)
Entry |
W. C. Beard: "Molecular Sieve Zeolites-I, Advances in Chemistry Series 101" pp. 237-247 (1971) (No Month Available). |
Atlas of Zeolite Structure Types, Meier & Ason 1992 pp. 100-101 No Month Available. |
Continuations (2)
|
Number |
Date |
Country |
Parent |
12807 |
Feb 1993 |
|
Parent |
430988 |
Nov 1989 |
|