Silica and silicate by precipitation at constant alkali number, and its use
View Patent ↗Precipitated silica or silicates, obtainable by acid precipitation of aqueous silicate solutions while maintaining a constant alkali number of at least 1.
1. A silicate having the following physicochemical characteristics:
BET surface area
from 50 to 700 m 2 /g
DBP absorption
from 100 to 450 g/100 g
Choline chloride
from 150 to 400 g/100 g (75% absorption
absorption
by weight aqueous solution)
CTAB surface area
from 50 to 350 m 2 /g
DBP/choline
less than 1.07.
chloride absorption
2. A composition comprising the silicate of claim 1 , and between 0.01 and 26% by weight based on total weight of an electrolyte.
3. The silicate of claim 1 , comprising between 1 and 50% by weight based on total weight of at least one metal ion selected from the group consisting of Al, Mg, Ca, Ti, Zr, Fe and mixtures thereof.
4. The silicate of claim 1 , having a modified Sears number of from at least 20 to 45.
5. The silicate of claim 1 , having a BET surface area of 180–210 m 2 /g, a DBP adsorption of 280–450 g/100 g, and a CTAB surface area of 130–200 m 2 /g.
6. A process for preparing precipitated silicate, comprising
simultaneously metering into an aqueous silicate solution more aqueous silicate solution and a Lewis and/or Brønsted acid to provide a mixture,
acidifying the mixture to a pH of 7–3.0 to provide an acidified mixture
optionally filtering the acidified mixture to obtain a filtered precipitated silicate,
optionally drying the filtered precipitated silicate,
wherein the metered addition of the aqueous silicate solution and the Lewis and/or Brønsted acid is carried out while maintaining a constant alkali number in the mixture of at least 1,
wherein at least one metal ion is added in the form of a salt or solution thereof prior to or during the simultaneous addition of acqueous silicate solution and Lewis and/or Brønsted acid, and
wherein said silicate has the following physicochemical characteristics:
BET surface area
from 50 to 700 m 2 /g
DBP absorption
from 100 to 450 g/100 g
Choline chloride
from 150 to 400 g/100 g (75% absorption
absorption
by weight aqueous solution)
CTAB surface area
from 50 to 350 m 2 /g
DBP/choline
less than 1.07.
chloride absorption
7. The process of claim 6 wherein the alkali number is at least 15.
8. The process of claim 6 , further comprising the addition of an electrolyte prior to or during the simultaneous addition of aqueous silicate solution and Lewis and/or Brønsted acid.
9. The process of claim 6 , wherein the at least one metal ion is selected from the group consisting of Al, Ti, Zr, Fe, Mg, Ca and mixtures thereof.
10. A method comprising contacting the precipitated silicate of claim 1 with a feed additive, a chemical intermediate, or a laundry detergent component.
11. A method comprising contacting the precipitated silicate of claim 1 with formic acid, propionic acid, lactic acid, phosphoric acid, choline chloride solution, a plant extract, a melamine resin, a coatings additive, a fragrance, or a detergent.
12. An elastomer, plastic, battery separator, toothpaste, catalyst support or flocculation assistant comprising the precipitated silicate of claim 1 .
13. A process for preparing precipitated silicate, comprising:
simultaneously metering into a vessel an aqueous silicate solution and a Lewis and/or Brønsted acid to provide a mixture,
acidifying the mixture to a pH of 7–3 to provide an acidified mixture,
optionally filtering the acidified mixture to obtain a filtered precipitated silicate,
optionally drying the filtered precipitated silicate,
wherein the metered addition of the aqueous silicate solution and the Lewis and/or Brønsted acid is carried out while maintaining a constant alkali number in the mixture of at least 1,
wherein at least one metal ion is added in the form of a salt or solution thereof prior to or during the simultaneous addition of aqueous silicate solution and Lewis and/or Brønsted acid, and
wherein said silicate has the following physicochemical characteristics:
BET surface area
from 50 to 700 m 2 /g
DBP absorption
from 100 to 450 g/100 g
Choline chloride
from 150 to 400 g/100 g (75% absorption
absorption
by weight aqueous solution)
CTAB surface area
from 50 to 350 m 2 /g
DBP/choline
less than 1.07.
chloride absorption
14. The process of claim 13 wherein the alkali number is at least 15.
15. The process of claim 13 , further comprising the addition of an electrolyte prior to or during the simultaneous addition of aqueous silicate solution and Lewis and/or Brønsted acid.
16. The process of claim 13 , wherein the at least one metal ion is selected from the group consisting of Al, Ti, Zr, Fe, Mg, Ca and mixtures thereof.
17. A composition comprising the silicate of claim 5 , and between 0.01 and 26% by weight based on total weight of an electrolyte.
18. The silicate of claim 1 , comprising between 1 and 50% by weight based on total weight of at least one metal ion selected from the group consisting of Al, Mg, Ca, Ti, Fe and mixtures thereof.
19. The process of claim 6 , wherein the at least one metal ion is selected from the group consisting of Al, Ti, Fe, Mg, Ca and mixtures thereof.
20. The process of claim 13 , wherein the at least one metal ion is selected from the group consisting of Al, Ti, Fe, Mg, Ca and mixtures thereof.