Process for producing metal oxides
View Patent ↗Method for producing a metal oxide powder in which a) a material stream I containing at least one vaporous hydrolysable metal compound, b) a material stream II containing oxygen and c) a material stream III containing at least one fuel gas are brought to reaction, wherein d) via a feed-in point provided in a pipe piece A, wherein the pipe piece A comprises one or more static mixer elements, the material stream I is introduced into the material stream II, or vice versa, and thereby generates the material stream IV, then e) via a feed-in point provided in a pipe piece B, wherein the pipe piece B comprises one or more static mixer elements, the material stream III is introduced into the material stream IV, and thereby generates the material stream V, f) the material stream V leaving the pipe piece B is introduced into a reaction chamber, ignited there and converted into a flame and g) the resultant solids are separated off.
1. A method for producing a metal oxide powder, the method comprising:
introducing a stream comprising a vaporous, hydrolysable metal compound into a stream comprising oxygen via a first feed-in point provided in a first pipe piece comprising one or more static mixer elements, or vice versa, to generate a first material stream;
introducing, at a velocity v B , a stream comprising at least one fuel gas into the first material stream, which has a velocity v A , via a second feed-in point provided in a second pipe piece comprising one or more static mixer elements, to generate a second material stream;
introducing the second material stream, which leaves the second pipe piece, into a reaction chamber to ignite the second material stream and to convert the second material stream into a flame, to obtain a mixture; and
separating solids from the mixture,
wherein
v B , which is at least 50 Nm/s, is greater than v A , which is at least 5 Nm/s, with the proviso that the stream comprising the vaporous, hydrolysable metal compound does not comprise a silicon compound as the sole metal compound;
a L A /D A ratio is 2-20, where L A is a length of the first pipe piece and D A is an inner diameter of the first pipe piece; and
a L B /D B ratio is 2-20, where L B is a length of the second pipe piece and D B is an inner diameter of the second pipe piece.
2. The method according to claim 1 , wherein the first and second pipe pieces are each designed as a flange mixer.
3. The method according to claim 2 , wherein the flange mixer comprises a single isolated feed-in point.
4. The method according to claim 1 , wherein oxygen is at least sufficient in order to convert the vaporous, hydrolysable metal compound and the at least one fuel gas.
5. The method according to claim 1 , wherein the vaporous, hydrolysable metal compound comprises a metal component selected from the group consisting of Al, Be, Ce, Fe, Ge, In, Nb, Si, Sn, Ta, Ti, V, W, Zn, and Zr.
6. The method according to claim 1 , wherein the vaporous, hydrolysable metal compound is selected from the group consisting of a chloride, a nitrate, a sulphate, an alkoholate, a carbonate, a carboxylate, an acetylacetonate, and a carbonyl.
7. The method according to claim 1 , further comprising:
introducing a stream comprising an aerosol of a metal compound into the second material stream.
8. The method according to claim 1 , further comprising:
introducing a stream comprising oxygen and/or steam into the reaction chamber.
9. The method according to claim 1 , further comprising:
cooling the mixture; and
steam-treating the solids.
10. The method according to claim 1 , wherein the L A /D A ratio is 3-6.
11. The method according to claim 1 , wherein the L B /D B ratio is 3-6.
12. The method according to claim 1 , wherein a v B /v A ratio is at least 4.
13. The method according to claim 1 , wherein v A ranges from 5 to 100 Nm/s.
14. The method according to claim 1 , wherein v B ranges from 100 to 1500 Nm/s.