Patent · US Expired

Method for reprocessing waste acid resulting from TiO2 production

US6440377B1 · kind B1 · utility

4Cited by

5References

17Claims

0Family size

Assignee

BAYER HEALTHCARE LLC · DE

Inventors

Gerhard Auer · Krefeld, DE
Gunter Lailach · Krefeld, DE
Ulrich Meisen · Kall, DE
Werner Schuy · Tönisvorst, DE

Key dates

Filing date	Sep 15, 2000
Grant date	Aug 27, 2002
Priority date	—
Expiry date	Sep 15, 2020

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC01P2006/64
WIPO fieldMaterials, metallurgy
WIPO sectorChemistry

Abstract

Process for the production of gypsum and also of an iron-oxide pigment from the waste acid that accumulates in the course of the production of titanium dioxide in accordance with the sulfate process, characterized in that in a first stage a partial neutralization of the waste acid is effected with a calcium compound subject to precipitation and optionally direct separation of gypsum, subsequently the remaining solution is neutralized further in a second stage subject to precipitation of a deposit containing Ti, Al, Cr, V and optionally Fe(III) and from the solution containing iron sulfate that is obtained after separation of the solids an iron-oxide pigment is produced in a third stage by addition of alkaline compounds and also of an oxidizing agent.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.