Patent · US Expired

Manufacture of acicular, ferrimagnetic iron oxide

US4213959A · kind A · utility

9Cited by

2References

2Claims

0Family size

Assignee

BASF SE

Inventors

Rudolf Brodt · Hirschberg, DE
Helmut Jakusch · Bischofswerda, DE
Eberhard Koester · Bischofswerda, DE
Werner Loeser · Ludwigshafen, DE
Manfred Ohlinger · Bischofswerda, DE
Wilhelm Sarnecki · Schifferstadt, DE
Werner Steck · Ludwigshafen, DE

Key dates

Filing date	Aug 3, 1978
Grant date	Jul 22, 1980
Priority date	—
Expiry date	Aug 3, 1998

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC01P2006/42
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

A process for the manufacture of acicular ferrimagnetic iron oxide by dehydrating acicular iron(III) oxide hydroxides to give acicular iron(III) oxides, then reducing these iron(III) oxides at from 300.degree. to 650.degree. C. by means of an organic compound which decomposes in this temperature range, and oxidizing the reduced product with an oxygen-containing gas at from 200.degree. to 500.degree. C., wherein the acicular iron(III) oxide hydroxides employed consist of a mixture of goethite and lepidocrocite, containing at least 60% of the latter, and the dehydration is carried out at from 250.degree. to 700.degree. C.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.