Evonik Degussa Gmbh

Degussa Aktiengesellschaft

Evonik Operations Gmbh

Peter Kress

Jürgen Meyer

Stipan Katusic

Michael Kraemer

Juergen Meyer

Andreas Gutsch

Edwin Staab

Guido Zimmermann

Harald Alff

Peter Albers

Michael Kroell

Harald Herzog

Armin Wiegand

Guenther Michael

Michael Hagemann

Horst Miess

Geoffrey J Varga

Günther Michael

Friedrich Georg Schmidt

Matthias Pascaly

Thomas Hasskerl

Stefan Heberer

Andrea Heinroth

Johan Anton

Franz Schmidt

Stefan Wieland

Hark-Oluf Asbahr

Jutta Zimmermann

Thomas Hennig

Heiko Morell

Tobias Renger

Michael Kröll

Sven Hill

Michael Krämer

Winfried Weber

Stipan Prof Katusic

A process for producing a metal oxide powder by flame spray pyrolysis where

Method for producing metal oxides by means of spray pyrolysis

The present invention relates to a process for preparing a pulverulent, porous crystalline metal silicate, comprising the following steps:

Production of pulverulent, porous crystalline metal silicates by means of flame spray pyrolysis

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.

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

Core-shell particles containing crystalline iron oxide in the core and amorphous silicon dioxide in the shell and in which

Iron-silicon oxide particles having an improved heating rate

Iron-silicon oxide particles with a core and an outer shell have improved heating rates in a magnetic field. The core contains maghemite, magnetite, and haematite. The outer shell is essentially or exclusively silicon dioxide. The crystallite diameter of the haematite determined by X-ray diffraction is greater than 120 nm. A ratio of the brightness of the Debye-Scherrer diffraction ring by electron diffraction at a lattice plane spacing of 0.20+/&#x2212;0.02 nm, comprising maghemite and magnetite, to the brightness of the Debye-Scherrer diffraction ring by electron diffraction at a lattice plane spacing of 0.25+/&#x2212;0.02 nm, comprising maghemite, magnetite and haematite, is no more than 0.2.

Iron-silicon oxide particles having an improved heating rate in an alternating magnetic and electromagnetic field

Iron-silicon oxide particles with a core-shell structure, which have a) a BET-surface area of 10 to 80 m/g, b) a thickness of the shell of 2 to 30 nm and c) a content of iron oxide of 60 to 90% by weight, of silicon dioxide of 10 to 40% by weight, based in each case on the enveloped particles, where d) the proportion of iron, silicon and oxygen is at least 99% by weight, based on the enveloped particles, and where e) the core is crystalline and the iron oxides comprise haematite, magnetite and maghemite, f) the shell consists of amorphous silicon dioxide and g) at least one compound or a plurality of compounds consisting of the elements silicon, iron and oxygen is/are present between shell and core.

Iron-silicon oxide particles with a core-shell structure

Process for preparing a mixed metal oxide powder, in which oxidizable starting materials are evaporated and oxidized, the reaction mixture is cooled after the reaction and the pulverulent solids are removed from gaseous substances, wherein as starting materials, at least one pulverulent metal and at least one metal compound, the metal and the metal component of the metal compound being different and the proportion of metal being at least 80% by weight based on the sum of metal and metal component from metal compound, together with one or more combustion gases, are fed to an evaporation zone of a reactor, where metal and metal compound are evaporated completely under nonoxidizing conditions, subsequently, the mixture flowing out of the evaporation zone is reacted in the oxidation zone of this reactor with a stream of a supplied oxygen-containing gas whose oxygen content is at least sufficient to oxidize the starting materials and combustion gases completely.

Process for preparing mixed metal oxide powders

Process for the production of a metal oxide powder having a BET surface area of at least 20 m/g by reacting an aerosol with oxygen in a reaction space at a reaction temperature of more than 700&#xb0; C. and then separating the resulting powder from gaseous substances in the reaction space, wherein

Process for the production of metal oxide powders

Nanoscale, pyrogenically produced zinc oxide having a BET surface area of 10 to 200 m/g, which is in the form of aggregates of anisotropic primary particles and whereby the aggregates display an average diameter of 50 to 300 nm. It is obtained from zinc powder, which is converted to zinc oxide powder in the four successive reaction zones, evaporation zone, nucleation zone, oxidation zone and quench zone. It can be used in sunscreen formulations.

Nanoscale zinc oxide, process for its production and use

Mixed oxide powder containing indium and tin, with a proportion of indium oxide of between 90 and 98 wt. % and a BET surface area of 40 to 120 m/g, which is in the form of aggregates having an average circumference of less than 500 nm, consists of at least 95% of an indium oxide phase and displays an oxygen content that is lower than the content that theoretically results from In2O3 and SnO2. It is produced by mixing a solution of an indium compound with a solution of a tin compound, atomising this mixture of solutions, pyrolysing the atomised mixture of solutions in a first zone of a reactor and in a second zone of the reactor, following pyrolysis, adding reducing gases to the pyrolysed mixture at one or more points in a quantity such that overall a reducing atmosphere is established in this second zone, and separating the resulting solid from the waste gases in a further, third zone, in which a reducing atmosphere likewise still prevails. It can be used for the production of transparent, electroconductive paints and coatings.

Nanoscale indium tin mixed oxide powder

Pyrogenically prepared zinc oxide powder having a BET surface area of from 10 to 200 m/g, which is in the form of aggregates, the aggregates being composed of particles having different morphologies, and 0-10% of the aggregates being in a circular form, 30-50% being in an ellipsoidal form, 30-50% being in a linear form and 20-30% being in a branched form. It is prepared by reacting a starting mixture containing zinc vapour, a combustible gas and steam or a mixture of steam and carbon dioxide in a flame with an oxygen-containing gas in an oxidation zone, cooling the hot reaction mixture in a quenching zone and separating the solid material from the gas stream, the amount of oxygen in the oxidation zone being greater than the amount necessary for the complete oxidation of the combustible gas and the zinc vapour. The zinc oxide powder can be used as a constituent of sun protection compositions for protection against UV radiation.

Zinc oxide powder aggregates present in circular, ellipsoidal, linear and branched form

Polycrystalline cerium oxide powder in the form of aggregates of primary particles with a specific surface of between 70 and 150 m/g, an average primary particle diameter of between 5 and 20 nm and an average, projected aggregate diameter of between 20 and 100 nm. It is produced in that an aerosol is reacted in a flame obtained from a hydrogen-containing combustible gas and primary air and the solid obtained is then separated from the gaseous substances.

Cerium oxide powder

Pyrogenically prepared, doped zinc oxide powder, wherein the doping component comprises at least one oxide from the group aluminum, gallium, indium, germanium, tin and is present in the doped zinc oxide powder in an amount of from 0.005 to 15 wt. %, and wherein the doped zinc oxide powder is in the form of aggregates of primary particles having a mean maximum diameter of from 30 to 400 nm. It is prepared by oxidation from zinc powder and at least one doping agent, wherein the process zones vaporisation, nucleation, oxidation and quenching are passed through and the doping agent is metered in in the nucleation zone, in which the temperature is below the boiling temperature of zinc. The doped zinc oxide powder can be used in electrically conductive lacquers and coatings.

Doped zinc oxide powder, process for its preparation, and its use

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Karlstein, Germany

Peter Kress