Process for the preparation of titanium dioxide

US4663131A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Rudolf Gerken · Krefeld, DE
• Gerhard Wiederhoft · Krefeld, DE
• Gunter Lailach · Krefeld, DE
• Walter Gutsche
• Wolfgang Muller · Dortmund, DE

Key dates

• Filing date: Nov 20, 1984
• Grant date: May 5, 1987
• Expiry date: Nov 20, 2004

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P10/20
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

In the preparation of titanium dioxide comprising autothermically digestion a titanium-containing raw material with sulphuric acid to form a solid relatively easily soluble digestion cake containing titanyl sulphate, extracting metal sulphates from this cake by water or dilute sulphuric acid, separating the undissolved residues and, optionally after crystallization of iron sulphate heptahydrate, hydrolyzing the titanyl sulphate to produce titanium oxide hydrate, and calcining the titanium oxide hydrate to titanium dioxide, the improvement which comprises adding to the raw material a metal sulphate and effecting the autothermic decomposition with sulphuric acid of about 80 to 88% concentration. Advantageously the acid is obtained by mixing dilute acid with concentrated sulphuric acid or oleum, some of the dilute acid and metal sulphate coming from a by-product filter cake produced in the course of the process.