Claims
- 1. A method for the production of water soluble polyaluminosilicate microgels which consist essentially of aggregates of very small particles of silica, surface aluminated and having a surface area of at least about 1000 meters.sup.2 /gram, said aggregates being formed into chains and crosslinked into three-dimensional networks, comprising the steps of
- (a) acidifying a dilute solution of alkali metal silicate containing about 0.1 to 6 wt. % SiO.sub.2 to a pH of between 2 and 10.5 to produce polysilicic acid, followed by
- (b) reacting a water soluble aluminate with the polysilicic acid before the polysilicic acid has gelled such that a product with an alumina/silica mole ratio greater than about 1/100 is obtained; and then
- (c) diluting the reaction mix before gelation has occurred to the equivalence of about 2.0 wt. % SiO.sub.2 or less to stabilize the microgels.
- 2. The method of claim 1 wherein the alkali metal silicate solution contains about 1 to 2 wt. % SiO.sub.2 and the acidification in step (a) is conducted stagewise over a period of about one hour or more.
- 3. The method of claim 2 wherein the pH is between 2.5 and 5.
- 4. The method of claim 1 wherein the alumina/silica mole ratio is between (1/15) 1/25 and 1/4.
- 5. The method of claim 3 wherein the alumina/silica mole ratio is between (1/15) 1/25 and 1/4.
- 6. The method of claim 1 wherein the alkali metal silicate is sodium silicate or polysilicate and the water soluble aluminate is sodium aluminate.
- 7. The method of claim 6 wherein the alkali metal silicate solution contains about 1 to 2 wt. % SiO.sub.2 and the acidification in step (a) is conducted stagewise over a period of about one hour or more.
- 8. The method of claim 7 wherein the pH is between 2.5 and 5.
- 9. The method of claim 8 wherein the alumina/silica mole ratio is between (1/15) 1/25 and 1/4.
- 10. The method of claim 9 wherein the alumina/silica mole ratio is between about 1/6 and 1/7.
- 11. The method of claim 1 wherein the alkali metal silicate solution contains about 3 to 6 wt. % SiO.sub.2.
- 12. The method of claim 6 wherein the alkali metal silicate solution contains about 3 to 6 wt. % SiO.sub.2.
- 13. An aqueous mixture comprising a water soluble polyaluminosilicate microgel which microgel consists essentially of aggregates of very small particles of silica, surface aluminated and having a surface area of at least about 1000 meters.sup.2 /gram, said aggregates being formed into chains and cross-linked into three-dimensional networks, and being present in the equivalence of about 2.0 wt % SiO.sub.2 or less and having an alumina to silica mole ratio of greater than 1 to 100.
- 14. The aqueous mixture of claim 13 wherein the microgel has a surface activity of about 0.6 milliequivalents per gram or greater.
Parent Case Info
This application is a continuation of application Ser. No. 07/213,479, filed Jun. 30, 1988, now abandoned, which in turn is a continuation-in-part of application Ser. No. 07/143,349, filed Jan. 13, 1988, now abandoned.
US Referenced Citations (9)
Foreign Referenced Citations (2)
Number |
Date |
Country |
8600100 |
Jan 1986 |
WOX |
8605826 |
Oct 1986 |
WOX |
Non-Patent Literature Citations (4)
Entry |
Iler, The Chemistry of Silica, John Wiley & Sons, New York (1979), pp. 174-176, 301-304, 407-410. |
Merrill et al., "Activated Silica, A New Chemical Engineering Tool", Chemical Engineering Progress, vol. 1, No. 1, (1947), pp. 27-32. |
Vail, Soluble Sicicates, vol. II, Reinhold Publishing Co., New York (1960), pp. 524-549. |
Sears, Analytical Chemistry, 28 (1956), pp. 1981-1983. |
Continuations (1)
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Number |
Date |
Country |
Parent |
213479 |
Jun 1988 |
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Continuation in Parts (1)
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Number |
Date |
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143349 |
Jan 1988 |
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