Process for the purification of waste water

US4145283A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Alwin Topp · Hofheim, DE
• Klaus Schmiedel
• Georg Schaeffer

Key dates

• Filing date: Dec 14, 1977
• Grant date: Mar 20, 1979
• Expiry date: Dec 14, 1997

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C02F11/08
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The waste water being formed upon the preparation of hydroxy aromatics, preferably of resorcinol and .beta.-naphthol, by caustic alkaline melt of the corresponding aryl-sulfonic acids or aryl sulfonates is purified by wet oxidation with oxygen or oxygen-containing gases at temperatures of from about 100.degree. to 370.degree. C. and under a pressure of from about 1 to 300 bars. The COD-decomposition rates amount to about 90% and more. When a hydroxy aromatic is prepared by means of a caustic soda melt, this process provides a sulfate, especially sodium sulfate, which is of sufficient purity for further use without complementary purification stages. The obtention of the pure salt is important for the economy of the process.