Basf Aktiengesellschaft

Basf Aktiengsellschaft

Gerhard Honecker

Manfred Ohlinger

Norbert Mueller

Heinz Stritzinger

Gerhard Wagner

Bernhard Boettcher

Helmut Reinicke

Heinz Spaehn

A process for the preparation of chromium(III) oxide by decomposing hydrated ammonium dichromate at elevated temperatures, an apparatus for carrying out this process and the use of the chromium(III) oxide thus prepared as a starting material for the synthesis of chromium dioxide.

Preparation of chromium(III) oxide

In order to reduce corrosion of the inside walls of a reactor made of iron or an iron alloy and used for the synthesis of chromium dioxide by hydrothermal conversion of chromium(VI) oxide with chromium oxides of lower valency, lead or bismuth is added at those points of the reactor at which an aqueous phase occurs during conversion and which do not contact the chromium oxides to be converted. The lead or bismuth may be used in metallic form or in the form of their oxides, hydroxides or salts.

Reducing corrosion in reactors used for the synthesis of chromium dioxide

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Ludwigshafen, Germany

Gerhard Honecker