Process for working up ammoniacal metal solutions including treating the wash water with an organic extraction solution

US6045763A · kind A · utility

Assignee

• Henkel Kommanditgesellschaft auf Aktien · DE

Inventors

• Ralf Kehl · Goldkronach, DE
• Werner Schwab · Monheim, DE

Key dates

• Filing date: Dec 12, 1997
• Grant date: Apr 4, 2000
• Expiry date: Dec 12, 2017

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S423/14
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The invention relates to a process for working up charged aqueous solutions, more especially etching solutions, which contain ammonia, at least one ammonium salt and metal ions in dissolved form and which accumulate in the treatment of substrates containing valuable metals, more especially copper-containing electronic sub-assemblies by contacting the aqueous solution with an organic water-immiscible extractant in one or more extraction stages to form an organic phase containing valuable metals and an aqueous phase, (b) washing the organic phase with a water-containing liquid in one or more successive washing stages wherein the water-containing liquid has a pH above 6.5 in the first washing stage and after said washing stage contacting the washing water before reuse with an organic extraction solution, and (c) conducting one or more stripping stages to transfer the valuable metals from the organic phase to an aqueous phase.