Deutsche Gold- Und Silber-scheideanstalt Vormals Roessler

Degussa Aktiengesellschaft

Peter Nauroth

Robert Kuhlmann

Gunter Turk

Heinz Esch

Helmut Reinhardt

Arthur Reisert

Rudolf Bode

Bernd Brandt

Albert Peters

Harald Buhler

Adam Becker

Gunther Turk

Edith Eisenmenger

Alfons Kreher

Eberhard Kilian

Otto Kuhnert

Buhler, Harald

Process for the production of cleansing, polishing and thickening silica for use in toothpastes, which is characterized in that using the conventional precipitation processes, silica suspensions are obtained of various particles sizes and particle densities and are mixed thoroughly together until the mixture is homogenous in the suspension phase and the resulting suspension mixture is treated in the conventional manner by filtering, drying and comminuting.

Precipitated silicas and process for their production and use

Precipitated silicas which have the following physicochemical characteristics, depending on the manner in which they are milled:

Process for preparing precipitated silica

There are disclosed precipitated silicas which are characterized by the following physical-chemical data:

Precipitated silicas having high structure and process for their

Cerium containing precipitated silica is disclosed as well as a process for its production as well as compositions hardenable to elastomers which contain the cerium containing precipitated silica. The precipitated silica

Cerium containing precipitated silica, process for its production

Finely divided precipitated silicic acid is obtained by the method of the invention. Compositions containing the finely divided precipitated silicic acid as a filler distributed in an elastomer such as an organopolysiloxane are disclosed.

Precipitated silicic acid, method and compositions containing same

There is prepared precipitated silica containing boron and having the following physical-chemical data

Boron containing precipitated silica

A silicic acid filter cake and suspension agent are fed to a container equipped with a stirrer having a peripheral speed of about 20-30 m/sec. The ratio of container diameter to stirrer diameter is about 3:1. The ratio of container diameter to level of filling is a maximum of about 1:2. The container contains at least about 1.5 to about 2 kg of silicic acid suspension, for each 1 kg of silicic acid filter cake which is added to the container. The contents of the container is mixed while maintaining a pH of at most about 4. A portion of the resulting silicic acid suspension is drawn off from the zone of highest turbulence in the container. An apparatus for carrying out the process is provided.

Apparatus for preparation of a sprayable precipitated silicic acid

A finely divided silicic acid having a pH&gt;6 is prepared by spray drying, in the presence of a base or basic-reacting substance, a highly concentrated silicic acid suspension having excess, unwanted acidity.

Process for the production of finely divided silicic acid by spray drying

Hydrophobic precipitated silicic acid is disclosed and its use as a reinforcing filler in plastic masses which are hardenable to form elastomers.

Hydrophobic precipitated silicic acid and compositions containing same

Free flowing, finely divided precipitated silicic acid granules of reduced dust content and reduced abrasion are obtained by a process including the step of subjecting a silicic acid suspension to intensive shearing action. Rubber compositions containing the precipitated silica produced in this way are also disclosed.

Precipitated silicic acid granules

A silicic acid filter cake and suspension agent are fed to a container equipped with a stirrer having a peripheral speed of about 20-30 m/sec. The ratio of container diameter to stirrer diameter is about 3:1. The ratio of container diameter to level of filling is at most about 1:2. The container contains at least about 1.5 to about 2 kg of silicic acid suspension, for each 1 kg of silicic acid filter cake which is added to the container. The contents of the container is mixed while maintaining a pH of at most about 4. A portion of the resulting silicic acid suspension is drawn off from the zone of highest turbulence in the container.

Process for preparation of a sprayable precipitated silicic acid

Modified silicic acids, gels, and silicates are produced by impregnation with a wax or a thermoplastic material, such as polyethylene. The silicic acids, silica gels, or silicates can be impregnated either as they are being formed or after they have formed by adding an aqueous suspension or dispersion of wax thermoplastic material to the silicic acids, gels or silicates. The mixture is then filtered, washed, dried, and finely ground. The organically modified silicic acids, gels, and silicates are useful as delustering agents in lacquer systems.

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Wesseling, Germany

Peter Nauroth