Process for producing metal oxide powders by means of flame spray pyrolysis

Patent metadata

Field	Value
Publication number	US-10384940-B2
Application number	US-201615740392-A
Country	US
Kind code	B2
Filing date	Jun 28, 2016
Priority date	Jun 29, 2015
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

Process for producing metal oxide powders by means of flame spray pyrolysis, in which an aerosol comprising a metal compound is introduced into a flame in a reactor and reacted therein, and the metal oxide powder obtained is separated from gaseous substances, wherein
a) the flame is formed by the ignition of an oxygen-containing gas (1) with a fuel gas,
b) the aerosol is obtained by joint atomization of a solution containing a metal compound and an atomization gas by means of one or more nozzles and
c) the ratio of the spray area to the cross-sectional reactor area is at least 0.2.

First claim

The invention claimed is:

1. A process for producing metal oxide powders by flame spray pyrolysis, the process comprising:
introducing an aerosol comprising a metal compound into a flame in a reactor and reacted therein, and separating the metal oxide powder obtained from gaseous substances, wherein
a) the flame is formed by the ignition of an oxygen-containing gas (1) with a fuel gas,
b) the aerosol is obtained by joint atomization of a solution comprising a metal compound and an atomization gas via one or more nozzles and
c) a ratio of the spray area to the cross-sectional reactor area is at least 0.2.

2. The process according to claim 1 , wherein the atomization form of the aerosol is a circular cone having a scatter region of 70-130°.

3. The process according to claim 1 , wherein a mean droplet size of the atomized aerosol is 10-150 μm.

4. The process according to claim 1 , wherein the aerosol is produced by virtue of the solution comprising the metal compound and the atomization gas flowing into a mixing chamber within the one or more nozzles and internals provided within the mixing chamber dividing the solution into individual droplets under the action of the atomization gas and aerosol from the mixing chamber being introduced through holes into the reactor.

5. The process according to claim 1 , wherein an oxygen-containing gas (2) that surrounds the flame is introduced into the reactor through one or more points in the reactor wall.

6. The process according to claim 5 , wherein an amount ratio of the oxygen-containing gas (2)/oxygen-containing gas (1)=0.1−2.

7. The process according to claim 1 , wherein a metal component of the metal compound is selected from the group consisting of Al, Co, Cr, Cu, Fe, Hf, In, Li, Mn, Mo, Nb, Ni, Si, Sn, Ta, Ti, V Y, Zn and Zr.

8. The process according to claim 1 , wherein the metal compound comprises carbon and a metal component.

9. The process according to claim 1 , wherein the metal compound is a silicon compound selected from the group consisting of silanes, polysiloxanes, cyclic polysiloxanes, silazanes and any desired mixtures thereof.

10. A process for producing a silica powder having a BET surface area of at least 50 m 2 /g and a carbon content of less than 0.1% by weight by flame spray pyrolysis, the process comprising:
introducing an aerosol comprising a silicon compound into a flame in a reactor and reacted therein, and the silica powder obtained is separated from gaseous substances,
wherein
a) the flame is formed by the ignition of an oxygen-containing gas (1) with a fuel gas,
b) the silicon compound is selected from the group consisting of silanes, polysiloxanes, cyclic polysiloxanes, silazanes and any mixtures thereof,
c) the aerosol is obtained by joint atomization of a solution comprising the silicon compound and an atomization gas via one or more nozzles and a ratio of the spray area to the cross-sectional reactor area is at least 0.2 and
d) an oxygen-containing gas (2) is additionally introduced into the reactor, where an amount ratio of oxygen-containing gas (2)/oxygen-containing gas (1)=0.1−2.

Assignees

• Evonik Degussa Gmbh

Inventors

• Katusic Stipan
• Kress Peter
• Alff Harald
• Renger Tobias
• Wiegand Armin

Classifications

• C01B13/34 Primary

  by oxidation or hydrolysis of sprayed or atomised solutions · CPC title

• C01B33/18 Primary

  Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof (preparation of aerogels by dehydrating gels C01B33/158; treatment to enhance the pigmenting or filling properties C09C) · CPC title

• C01B33/181

  by a dry process · CPC title

• C01G1/02

  Oxides · CPC title

• C01P2006/80

  Compositional purity · CPC title