Method of manufacturing acicular goethite

US4422910A · kind A · utility

Assignee

• U.S. Philips Corporation · US

Inventors

• Heinz Scholz · Aachen, DE
• Wolfgang E. Schnitker · Krefeld, DE
• Ernst Klein · Düsseldorf, DE

Key dates

• Filing date: Aug 2, 1982
• Grant date: Dec 27, 1983
• Expiry date: Aug 2, 2002

Classification

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

Abstract

A suspension of a poorly water-soluble iron (II) containing compound in a liquid which consists substantially of water and is preferably alkaline is oxidized, to form goethite crystals and particles. The crystals and particles are filtered off, washed and dried. From a thermodynamic point of view, "more monoenergetic" particles are obtained than particles manufactured according to conventional production processes, when electrolytic oxidation processes are used, in particular, when the oxidation to goethite occurs entirely or partly by a (preferably periodic) electrolysis process. The electrolysis process may be combined with oxidation by an oxidation agent, preferably an oxidizing gas or gas mixture. Furthermore, it is possible to first oxidize the iron (II) containing compound completely to goethite by an oxidation agent, preferably an oxidizing gas or gas mixture, and to then subject the resulting suspension to an electrolytic oxidation after-treatment which preferably occurs periodically.