Process for the preparation of titanium dioxide

US5229087A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Karl-Heinz Schultz · Krefeld, DE
• Gunter Lailach · Krefeld, DE
• Rudolf Gerken · Krefeld, DE

Key dates

• Filing date: May 14, 1990
• Grant date: Jul 20, 1993
• Expiry date: May 14, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22B34/1259
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A process for the preparation of titanium dioxide by the sulphate process in which titanium raw materials are decomposed with sulphuric acid, the resulting titanyl sulphate is hydrolyzed, the waste acid is separated from the hydrolyzate and evaporated to a concentration of 60 to 70%, sulphuric acid is separated from the solid metal sulphates, and the sulphuric acid which has been concentrated by evaporation is used again for the decomposition of the titanium raw material, the improvement wherein the 60 to 70% sulphuric acid is concentrated to 70 to 80% H.sub.2 SO.sub.4 in a further evaporation stage and the concentration of a part of this sulphuric acid is raised to a concentration of 98 to 99% H.sub.2 SO.sub.4 by the absorption of SO.sub.3 and then used together with the remainder of the above-mentioned 70 to 80% sulphuric acid for the decomposition of titanium raw materials.