Process for the precipitation of heavy metal ion-polycarboxylate complexes

US3956121A · kind A · utility

Assignee

• Deutsche Gold- und Silber-Scheideanstalt Vormals Roessler

Inventors

• Heinz Haschke · Bad Sankt Leonhard im Lavanttal, AT
• Helmut Knorre · Seligenstadt, DE
• Gerhard Morlock · Hanau, DE
• Gerhard Pohl · St. Georgen, DE

Key dates

• Filing date: Nov 11, 1974
• Grant date: May 11, 1976
• Expiry date: Nov 11, 1994

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C02F2101/303
• WIPO field: Environmental technology
• WIPO sector: Chemistry

Abstract

A process for precipitating heavy metal ion-polycarboxylate complexes from solution, said process comprising adding to a solution containing at least one of said complexes an aqueous solution of a water soluble aluminum salt, the anion of which does not form any water soluble complexes with said heavy metal ions to be precipitated or optionally such anion-heavy metal complexes having a stability constant, expressed as their decadic logarithm, of less than 2; wherein 0.9 to 1.8 moles of aluminum ions are employed per equivalent of polycarboxylate; and adjusting the pH of the resulting reaction mixture to about 6.5 to about 9.0 with an alkali metal carbonate.