Degussa Aktiengesellschaft

Degussa Gmbh

Degussa - Huls Ag

Evonik Degussa Gmbh

Werner Hartmann

Dieter Kerner

Helmut Mangold

Peter K Kleinschmit

Hauke Jacobsen

Juergen Meyer

Stipan Katusic

Thomas Rudolph

Edgar Koberstein

Klaus Deller

Bernd Engler

Rudolf Schwarz

Helmfried Krause

Karl-Anton Starz

Reinhold Brand

Manfred Ettlinger

Uwe Schachtely

Andreas Schulz

Norbert Giesecke

Ralph Brandes

Johannes Ohmer

Hans Lansink-Rotgerink

Jorg Sperlich

Henning Karbe

Thomas Hennig

Martin Foerster

Richard Akam

Pyrogenically, especially flame-hydrolytically produced zirconium dioxide powder with a specific surface area between 20 and 200 m /g, a primary particle size between 7 and 100 nm, a tamped density of the deacidified and non-deacidified zirconium dioxide between 40 and 150 g/l with Sears numbers of the deacidified and non-deacidified zirconium dioxide between 1 and 20 ml/2 g and with a chlorine content of the deacidified zirconium dioxide less than 0.6% by weight. These are produced by evaporating zirconium halides, mixing the vapors alone or together with a carrier gas in a burner with air, oxygen, nitrogen and hydrogen, causing the gases to react with each other in a flame in a closed burner chamber, cooling off the waste gases and the zirconium dioxide in a heat exchanger unit, separating the waste gases from the zirconium dioxide and removing any halide remnants adhering to the zirconium dioxide by a heat treatment with moistened air.

Zirconium dioxide powder, method of its production and use

A titanium dioxide powder/iron oxide mixed oxide which is prepared from FeCl and TiCl using a pyrogenic, especially a flame hydrolytic method. A further possibility is to coat pyrogenically, especially flame hydrolytically prepared titanium dioxide with iron oxide in aqueous dispersion. Both of these titanium dioxide powders which contain iron oxide may be used as a UV absorber in sunscreens.

Titanium dioxide powder which contains iron oxide

The invention relates to pigments consisting of substantially spherical particles with a mean particle diameter of less than 10 .mu.m, on the basis of an oxidic or silicate substrate material with noble metal distributed extremely finely on and/or in the particles. Preferred pigments are purple-colored and are based on an oxide from the series SiO.sub.2, SnO.sub.2 and ZrO.sub.2 and gold as noble metal. The pigments are suitable for the production of ceramic decorations and for the dyeing of plastics, synthetic films and fibers as well as lacquers. Exceptional application properties are obtained by virtue of the spherical shape. The pigments are obtainable by a spray-pyrolysis process in which an aerosol consisting of a solution of at least one noble metal compound and an oxide- or silicate-forming precursor is subjected to pyrolysis; the pigment is separated from the pyrolysis gas.

Spherical pigments, process for producing them and use thereof

Surface-modified, pyrogenically produced mixed oxides which contain two or more components of the series SiO.sub.2, Al.sub.2 O.sub.3, TiO.sub.2, ZrO.sub.2, Fe.sub.2 O.sub.3, Nb.sub.2 O.sub.5, V.sub.2 O.sub.5, WO.sub.3, SnO.sub.2, GeO.sub.2 and have been surface-modified with one to several compounds of the following groups:

Surface-modified, pyrogenically produced mixed oxides, method of their

Silica with the following physico-chemical properties:

Silanized silica

A finely-divided cerium metal/metalloid oxide mixture, containing pyrogenically produced metal/metalloid oxide and 0.001 to 95 wt. % cerium oxide, has a specific surface area between 10 and 400 m.sup.2 /g. The mixture is produced by mixing pyrogenically produced metal/metalloid oxide, having a specific surface area between 30 and 400 m.sup.2 /g, with a cerium compound decomposable to an oxide at elevated temperature, the cerium compound being thermally decomposed to the oxide. The cerium oxide-metal/metalloid oxide mixture can be used as a polishing agent or filler.

Cerium oxide-metal/metalloid oxide mixture

In order to produce precious metal powders of uniform particle size and low BET specific surface, appropriate aerosols are introduced into a flame reactor, whereby the aerosols are first freed of solvent as completely as possible by a thermal treatment.

Process for producing precious metal powders

Granules based on silicon dioxide and having the properties:

Granules based on pyrogenically prepared silicon dioxide, methods for

Flame-hydrolytically produced titanium dioxide mixed oxide having a BET surface of 10 to 150 m.sup.2 /g and 1 to 30% by weight aluminum oxide or 1 to 30% by weight silicon dioxide is produced by evaporating aluminum chloride or silicon tetrachloride, transferring the evaporated aluminum chloride or silicon tetrachloride, together with an inert gas, into the mixing chamber of a burner, mixing them with hydrogen, air and gaseous titanium tetrachloride, burning the resulting 4-component mixture in the reaction chamber of the burner, and separating the titanium dioxide mixed oxide from the gaseous reaction products.

Flame-hydrolytically produced titanium dioxide mixed oxide, method of

Flame-hydrolytically produced titanium dioxide mixed oxide method of its

Silicon-aluminum mixed oxide powder which is flamehydrolytically produced and has a composition of 65 to 85% by weight Al.sub.2 O.sub.3, remainder SiO.sub.2 and an amorphous structure, in which each primary particle contains components of SiO.sub.2 and of Al.sub.2 O.sub.3, the primary particles are between 7 and 80 nm, preferably 10 and 40 nm in size and the specific surface of the powder is between 20 and 200 m.sup.2 /g. The powder is used for the production of mullite and sintered compacts manufactured from it.

Silicon-aluminum mixed oxide

Silicon-aluminum mixed oxide powder which is flame-hydrolytically produced and has a composition of 65 to 85% by weight Al.sub.2 O.sub.3, remainder SiO.sub.2 and an amorphous structure, in which each primary particle contains components of SiO.sub.2 and of Al.sub.2 O.sub.3, the primary particles are between 7 and 80 nm, preferably 10 and 40 nm in size and the specific surface of the powder is between 20 and 200 m.sup.2 /g. The powder is used for the production of mullite and sintered compacts manufactured from it.

Titanium dioxide compacts are produced by intensively mixing pyrogenically produced titanium dioxide in the presence of deionized water with a wetting agent and/or with a base and/or optionally with a binder and/or optionally with an auxiliary deformation agent and/or optionally with a pore former, extruding the mass thus obtained at pressures between 5 and 100 bars to form shaped articles, drying the shaped articles at temperatures between 50.degree. and 120.degree. C. and subsequently calcining the shaped articles in the ambient air at temperatures of 400.degree. to 700.degree. C. for 1 to 5 hours.

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Babenhausen, Germany

Werner Hartmann