Process for the protection against corrosion of cast iron boilers

US4148858A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Helmold von Plessen · Kelkheim, DE
• Kurt Bodenbenner · Wiesbaden, DE

Key dates

• Filing date: May 12, 1977
• Grant date: Apr 10, 1979
• Expiry date: May 12, 1997

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23F11/02
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Gray cast iron can be protected against corrosion by the vapors of boiling concentrated sulfuric acid when a compound containing positive nitrogen, e.g., nitrogen oxide, is introduced into the gas space between the cast iron to be protected and the boiling sulfuric acid.