Bayer Aktiengesellschaft

Lanxess Deutschland Gmbh

Wolfgang Oehlert

Wilfried Burow

Horst Brunn

Ulrike Pitzer

Heribert Bade

Friedrich Jonas

Gunter Buxbaum

Carsten Rosenhahn

Waldemar Czaplik

Herbert Kunstmann

Juergen Kischkewitz

Huajun Li

Bernd Iskluth

The present invention relates to an improved process for producing red iron oxide pigments by the Penniman process with nitrate (also called nitrate process or direct red process) and to apparatus for implementing this process, and also to the use of the plant for producing red iron oxide pigments by the Penniman process with nitrate.

Production of red iron oxide pigment

The present invention relates to zinc ferrite colour pigments, including a process for preparing and using them and, more particularly, the present invention relates to light-coloured zinc ferrite colour pigments having enhanced thermal stability, a magnesium content of from 0.01%-0.4% by weight, a color difference &#x394;E* according to DIN 53 772 at 260&#xb0; C. of &#x3c;3.0, a color difference &#x394;E* according to DIN 53 772 at 300&#xb0; C. of &#x3c;5.0, and a lightness of L*, measured in PE-HD full shade according to DIN 55 772 of &#x3e;52.5.

Heat-stable zinc ferrite colour pigments, process for preparing them and their use

Pure-coloured iron oxide yellow pigments having a silking index of less than 5 and a heat resistance of greater than 220.degree. C. in polyethylene for at least 5 minutes are obtained by oxidation of metallic iron with nitrobenzene in an acid medium in the presence of compounds of elements chosen from main groups 3 and 4 of the periodic table.

Heat-stable iron oxide yellow pigments

The invention relates to the use of synthetic (synthetically produced) iron raw materials to prepare iron oxide pigments in the Penniman process and other iron-dissolution processes.

Use of synthetic, iron raw materials for preparing iron oxide pigments

The invention relates to the use of synthetically produced, bainite-rich iron raw materials to prepare iron oxide pigments.

Use of synthetic, bainite-rich iron raw materials for preparing iron

The present invention relates to iron oxide pigments with an Fe(II) content of at least 5 wt. %, calculated as FeO, which have at least one inorganic after-treatment layer and at least one organic after-treatment coating, a process for preparing these iron oxide pigments and their use.

Thermally stable iron oxide pigments, a process for their preparation

The invention relates to clean color shade, yellow-tinged red iron oxide pigments, and a process for their manufacture, and their use.

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Krefeld, Germany

Wolfgang Oehlert