Evonik Degussa Gmbh

Evonik Degussa Gmeh

Ralph Hofmann

Uwe Schachtely

Rainer Friehmelt

Christoph Batz-Sohn

Werner Niedermeier

Frank Menzel

Joachim Fröhlich

Roland Schaffer

Christian Schulze-Isfort

Herbert Habermann

Guenter Stein

Ann Gray

Margarete Drechsler

Günter Stein

Joachim Froehlich

Process for preparing an aluminum oxide powder which is present in the form of aggregated primary particles and comprises at least 85% by weight of alpha-aluminum oxide, in which an aluminum oxide powder which a) is present in the form of aggregated primary particles, b) is selected from the group consisting of gamma-aluminum oxide, theta-aluminum oxide, delta-aluminum oxide and/or X-ray amorphous aluminum oxide, and c) has a tamped density of at least 250 g/l, is subject to a heat treatment at 13000 C or more and subsequently milled. Aluminum oxide powder which can be obtained by this process. Aluminum oxide powder in the form of aggregated primary particles having a BET surface area of from 3 to 30 m2/g, in which the proportion of alpha-aluminum oxide is at least 85% by weight and the ratio dgo/dio of the weight distribution of the primary particles is at least 2.8. Use as constituent of fluorescent tubes.

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The use of Sch&#xfc;lpen based on pyrogenically produced silicon dioxide in pharmaceutical compositions is described.

Use of roll compacted pyrogenically produced silicon dioxide in pharmaceutical compositions

Pyrogenic titanium dioxide is compressed to slugs by preliminarily deaerating it, compressing it to slugs, and crushing the slugs and optionally classifying them. The slugs are characterized by a tamped density (to DIN EN ISO 787-11) of 500 to 1200 g/l.

Pyrogenic titanium dioxide compressed to slugs

Rubber mixtures are prepared by using, alongside the other constituents, pyrogenically prepared silicon dioxide in the form of crusts whose tamped bulk density (to DIN EN ISO 787-11) is from 185 to 700 g/l.

Process for preparation of rubber mixtures containing silicon dioxide

Pyrogenically prepared silicon dioxide is compacted to give crusts, in that it is subject to preliminary de-aeration, and is compacted to give crusts, and the crusts are broken and, if appropriate, classified. The tamped bulk density (to DIN EN ISO 787-11) of the silicon dioxide compacted to give crusts is from 185 to 700 g/l. It can be used as filler in rubber mixtures.

Pyrogenically prepared silicon dioxide compacted to give crusts

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Buchen, Germany

Ralph Hofmann