Continuous manufacture of sodium dithionite solutions by cathodic reduction

US4144146A · kind A · utility

Assignee

• BASF SE

Inventors

• Bernd Leutner · Bischofswerda, DE
• Gotthard Scizi · Bad Dürkheim, DE
• Siegmar Lukas · Ludwigshafen, DE
• Siegfried Schreiner · Ludwigshafen, DE
• Erfried Voelkl

Key dates

• Filing date: Oct 5, 1977
• Grant date: Mar 13, 1979
• Expiry date: Oct 5, 1997

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C25B1/14
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

Concentrated dithionite solutions are produced by cathodic reduction of an aqueous solution, containing sulfite and/or bisulfite, which is circulated by pumping. The cathode and anode chambers are separated from one another by a permselective cation exchanger membrane. The catholyte must be circulated at least 10 times per hour and the selective catholyte volume outside the cell, defined as EQU a = V.sub.total -V.sub.C /V.sub.total, Should be less than 0.9.