Method for producing iron oxide pigments from waste acid resulting from TiO2 production

US6530987B1 · kind B1 · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Gerhard Auer · Krefeld, DE
• Gunter Lailach · Krefeld, DE
• Ulrich Meisen · Kall, DE
• Werner Schuy · Tönisvorst, DE
• Udo Julius · Neukirchen, DE

Key dates

• Filing date: Sep 15, 2000
• Grant date: Mar 11, 2003
• Expiry date: Sep 15, 2020

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2006/80
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Process for the preparation of iron oxide pigments from the waste acid resulting from the preparation of titanium dioxide by the sulfate process, characterized in that in a first stage a partial neutralization of the sulfuric acid contained in the waste acid is performed with compounds from the group comprising metallic iron and/or iron compounds, the sulfuric acid is optionally further neutralized with a further alkaline compound, the precipitate containing Ti, Al, Cr and V compounds is separated from the resultant reaction product and an iron oxide yellow pigment or iron oxide black pigment is precipitated from the resultant iron sulfate-containing solution by addition of alkaline compounds as well as an oxidizing agent, each pigment being able to be baked to form an iron oxide red pigment.