Manufacture of acicular ferrimagnetic iron oxide

US4367214A · kind A · utility

Assignee

• BASF SE

Inventors

• Wilhelm Sarnecki · Schifferstadt, DE
• Laszlo Marosi · Ludwigshafen, DE
• Horst Autzen · Freinsheim, DE
• Manfred Ohlinger · Bischofswerda, DE
• Werner Steck · Ludwigshafen, DE

Key dates

• Filing date: Jul 31, 1980
• Grant date: Jan 4, 1983
• Expiry date: Jul 31, 2000

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2006/42
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A process for the manufacture of acicular ferrimagnetic iron oxide by heating iron(III) oxide or iron(III) oxide hydroxide at 220.degree.-460.degree. C. under a water vapor partial pressure of not less than 30 mbar, reducing the resulting product to magnetite by means of hydrogen and/or CO and/or an organic compound which can decompose in the presence of iron oxide, and then oxidizing the magnetite with an oxygen-containing gas to give acicular ferrimagnetic iron oxide of the formula FeO.sub.X, where X is from 1.33 to 1.50.