Process for producing sulfuric acid from waste acid and iron sulfate

US4163047A · kind A · utility

Assignees

• Metallgesellschaft AG · DE
• BAYER HEALTHCARE LLC · DE

Inventors

• Karl-Heinz Dorr
• Georg Daradimos · Maintal, DE
• Hugo Grimm
• Georg Schmidt · Lindflur, DE
• Rudolf Gerken · Krefeld, DE
• Christoph Mucke · Krefeld, DE
• Hermann Wieschen

Key dates

• Filing date: Jun 30, 1977
• Grant date: Jul 31, 1979
• Expiry date: Jun 30, 1997

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S423/02
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A process for the recovery of sulfuric acid from waste sulfuric acid containing iron sulfate and from solid iron sulfate of high water content of crystallization which consists essentially of: A. concentrating waste sulfuric acid to an acid concentration of 25-55 weight percent, based upon the suspension, by removing water therefrom; B. mixing the concentrated acid of Step A with recycled concentrated sulfuric acid obtained from Step E to form a resultant acid mixture of acid concentration of 30-65 weight percent, based upon the suspension; C. adding said solid iron sulfate of high water content of crystallization to the acid mixture of Step B thereby obtaining iron sulfate of low water content of crystallization; D. separating the iron sulfate of low water content from the resultant sulfuric acid solution of Step C; E. concentrating the separated sulfuric acid solution of Step D to an acid concentration of 45-70 weight percent, based on salt-free acid, and recycling at least a portion thereof to Step B; and F. thermally decomposing the iron sulfate from Step D to produce iron oxide and sulfur dioxide.