Processes for the preparation of alkali metal dichromates and chromic acid

US5051155A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Helmut Klotz · Friedrichshafen, DE
• Hans-Dieter Pinter · Wermelskirchen, DE
• Rainer Weber · Leverkusen, DE
• Hans-Dieter Block · Cologne, DE
• Norbert Lonhoff · Leverkusen, DE

Key dates

• Filing date: Dec 21, 1990
• Grant date: Sep 24, 1991
• Expiry date: Dec 21, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C25B1/22
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A process for the preparation of alkali metal dichromates and chromic acid by the electrolysis of monochromate and/or dichromate solutions in an electrolytic cell in which the anode and cathode chambers are separated by cation exchange member, the improvement wherein the formation of deposits on the membrane is prevented comprising continuously introducing a solution containing chromate at a pH of about 3 to 10 into the cathode chamber during the electrolysis.