Process for regenerating spent pickle liquid containing ZrF.sub.4

US4330342A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Wolfgang Fennemann · Karben, DE
• Jurgen Haldorn · Oberursel, DE

Key dates

• Filing date: Feb 26, 1981
• Grant date: May 18, 1982
• Expiry date: Feb 26, 2001

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23G1/36
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A process for regenerating a spent HF-HNO.sub.3 pickle which contains ZrF.sub.4, which comprises heating said spent pickle to above 40.degree. C., adding dissolved NaOH to said so-heated pickle, thereafter cooling said so-treated pickle to a temperature below 20.degree. C. whereby to precipitate Na.sub.2 ZrF.sub.6 and removing said Na.sub.2 ZrF.sub.6 from said so-cooled pickle whereby to regenerate the same.