Process for the purification of industrial gases or waste gases

US4731232A · kind A · utility

Assignee

• Degussa AG · DE

Inventors

• Joachim Fischer · Rodgau, DE
• Helmut Knorre · Seligenstadt, DE

Key dates

• Filing date: Jul 23, 1986
• Grant date: Mar 15, 1988
• Expiry date: Jul 23, 2006

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01D53/54
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

In purifying gas wash waters containing cyanide with formaldehyde, the exact dosing of formaldehyde presents a problem, especially with strongly fluctuating cyanide contents. By continuous potentiometric measurement in a side stream which is regulated to a pH of 7 to 10, while the pH of the main stream remains unchanged, the formaldehyde can be adjusted safely to any cyanide content.