Methods for processing fumed metallic oxides

Patent metadata

Field	Value
Publication number	US-9969621-B2
Application number	US-201615146037-A
Country	US
Kind code	B2
Filing date	May 4, 2016
Priority date	May 4, 2016
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

Novel methods for processing fumed metallic oxides into globular metallic oxide agglomerates are provided. The methodology may allow for fumed metallic oxide particles, such as fumed silica and fumed alumina particles, to be processed into a globular morphology to improve handling while retaining a desirable surface area. The processes may include providing fumed metallic oxide particles, combining the particles with a liquid carrier to form a suspension, atomizing the solution of suspended particles, and subjecting the atomized droplets to a temperature range sufficient to remove the liquid carrier from the droplets, to produce metallic oxide-containing agglomerations.

First claim

What is claimed is:

1. A method for processing fumed silica into silica agglomerations comprising:
providing fumed silica particles, wherein the fumed silica particles have a first Brunauer Emmett Teller (BET) surface area of greater than about 50 meters squared per gram (m 2 /g), and are characterized by a dominant branched morphology comprising from 5 nanometer (nm) to 50 nm primary particles, with an average bulk density of less than 64 kilograms per cubic meter (kg/m 3 );
combining the fumed silica particles with a liquid carrier to form a solution of suspended fumed silica particles, wherein the solution of suspended fumed silica particles comprises from about 2 weight percent (wt %) to about 8 wt % of the fumed silica particles;
atomizing the solution of suspended fumed silica particles to produce silica-containing droplets, wherein at least a majority of the silica-containing droplets are characterized by a droplet diameter of about 250 nm to about 100 micrometers (μm) and a fumed silica particle weight percentage of from about 2 wt % to about 8 wt %; and
subjecting the silica-containing droplets to a temperature of from about 50° C. to about 1500° C. for a period of time of at least about 0.5 seconds to substantially remove the liquid carrier from the silica-containing droplets to produce the silica agglomerations, wherein substantially all of the produced silica agglomerations exhibit a second BET surface area that is at least about 75% of the first BET surface area, and a dominant globular morphology characterized by an average bulk density of greater than 64 kg/m 3 .

2. The method of claim 1 , wherein the method further comprises collecting at least a majority of the produced silica agglomerations by filtration or condensation.

3. The method of claim 1 , wherein the atomizing step comprises aerosolizing, spray drying, using an ultrasonic transducer, or any combination thereof, to produce the silica-containing droplets.

4. The method of claim 1 , wherein the atomizing step comprises injecting a carrier gas into the solution of suspended fumed silica particles.

5. The method of claim 4 , wherein the carrier gas is selected from the group consisting of nitrogen, air, or combinations thereof.

6. The method of claim 1 , wherein the liquid carrier is selected such that the produced silica agglomerations have substantially the same chemical composition as the provided fumed silica particles, wherein the produced silica agglomerations are comprised of less than about 2 wt % of impurities.

7. The method of claim 1 , wherein the liquid carrier is comprised of H 2 O.

8. The method of claim 1 , wherein the method comprises doping the solution of suspended fumed silica particles such that the produced silica agglomerations do not have substantially the same chemical composition as the provided fumed silica particles.

9. The method of claim 8 , wherein the doping step comprises selecting the liquid carrier such that the produced silica agglomerations do not have substantially the same chemical composition as the provided fumed silica particles.

10. The method of claim 8 , wherein the doping step comprises introducing a carrier gas to the solution of suspended fumed silica particles such that the produced silica agglomerations do not have substantially the same chemical composition as the provided fumed silica particles.

11. The method of claim 1 , wherein the fumed silica particles have a first BET surface area from about 200 m 2 /g to about 600 m 2 /g.

12. The method of claim 1 , wherein substantially all of the produced silica agglomerations exhibit a second BET surface area that is at least about 90% of the first BET surface area.

13. The method of claim 1 , wherein the silica-containing droplets comprise from about 3 wt % to about 6 wt % of fumed silica particles.

14. The method of claim 1 , wherein the solution of suspended fumed silica particles comprises from about 3 wt % to about 6 wt % of fumed silica particles.

15. The method of claim 1 , wherein the silica-containing droplets comprise about 6 wt % of fumed silica particles.

16. The method of claim 1 , wherein the solution of suspended fumed silica particles comprises about 6 wt % of fumed silica particles.

17. The method of claim 1 , wherein the silica-containing droplets are subjected to a temperature of from about 400° C. to about 1500° C.

18. The method of claim 1 , wherein the subjecting step comprises passing the silica-containing droplets through a tube furnace.

19. The method of claim 18 , wherein the subjecting step comprises passing the silica-containing droplets through a tube furnace at a flow rate of from about 3 liters per minute (L/min) to about 50 L/min.

20. The method of claim 1 , wherein the method is substantially reversible, such that the silica agglomerations may be reverted into a solution of suspended fumed silica particles.

21. The method of claim 1 , further comprising,
redispersing the silica agglomerations into the liquid carrier to form a solution of suspended fumed silica particles, wherein the solution of suspended fumed silica particles comprises from about 2 wt % to about 8 wt % of fumed silica particles.

22. A method for processing fumed metallic oxides comprising:
providing fumed metallic oxide particles, wherein the fumed metallic oxide is selected from the group consisting of SiO 2 , Al 2 O 3 , TiO 2 , CeO 2 , B 2 O 3 , ZrO 2 , GeO 2 , WO 3 , Nb 2 O 5 , and combinations thereof, wherein the fumed metallic oxide particles have a first Brunauer Emmett Teller (BET) surface area of greater than about 50 m 2 /g, and a dominant branched morphology comprising from 5 nm to 50 nm primary particles;
combining the fumed metallic oxide particles with a liquid carrier to form a solution of suspended fumed metallic oxide particles, wherein the solution of suspended fumed metallic oxide particles comprises from about 2 wt % to about 8 wt % of the fumed metallic oxide particles;
atomizing the solution of suspended fumed metallic oxide particles to produce metallic oxide-containing droplets, wherein at least a majority of the metallic oxide-containing droplets are characterized by a droplet diameter of about 250 nm to about 100 μm and a fumed metallic oxide particle weight percentage of from about 2 wt % to about 8 wt %; and
subjecting the metallic oxide-containing droplets to a temperature of from about 50° C. to about 1500° C. for a period of time of at least about 0.5 seconds to substantially remove the liquid carrier from the metallic oxide-containing droplets to produce metallic oxide agglomerations, wherein substantially all of the produced metallic oxide agglomerations exhibit a dominant globular morphology and a second BET surface area that is at least about 75% of the first BET surface area.

23. The method of claim 22 , wherein the fumed metallic oxide particles are fumed alumina (Al 2 O 3 ) particles and the produced metallic oxide agglomerations are alumina agglomerations.

24. The method of claim 23 , wherein the fumed alumina particles have a first BET surface area from about 80 m 2 /g to about 150 m 2 /g.

25. The method of claim 23 , wherein the fumed alumina particles have an average bulk density of less than 60 kg/m 3 and the produced alumina agglomerations have an average bulk density of greater than 40 kg/m 3 .

26. The method of claim 22 , wherein the fumed metallic oxide is silica (SiO 2 ).

Assignees

• Saudi Arabian Oil Co

Inventors

• Ostraat Michele Louisa

Classifications

• C01P2006/12

  Surface area · CPC title

• C01G23/047

  Titanium dioxide · CPC title

• C01B35/1027

  Oxides · CPC title

• C01P2004/50

  Agglomerated particles · CPC title

• B01J2/00

  Processes or devices for granulating materials {, e.g. fertilisers} in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic · CPC title