Process for the recovery of metals from used nickel/metal hydride storage batteries

US5858061A · kind A · utility

Assignee

• Varta Batterie Aktiengesellschaft · DE

Inventors

• Klaus Kleinsorgen · Kelkheim, DE
• Uwe Kohler · Kelkheim, DE
• Alexander Bouvier · Krumpendorf, AT
• Andreas Folzer · Althofen, AT

Key dates

• Filing date: Jun 16, 1997
• Grant date: Jan 12, 1999
• Expiry date: Jun 16, 2017

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02W30/84
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

In the recycling of used nickel/metal hydride storage batteries, the battery scrap is dissolved in sulphuric acid after mechanical separation of the coarse constituents by magnetic and air separation. A solvent extraction is performed with the digestion solution, from which the rare earths (from the hydrogen-storage alloys in the negative electrodes) and iron and aluminum have been selected by precipitation, under conditions pH, choice of solvent, volumetric ratio of the phases) which are such that the aqueous phase contains nickel and cobalt in the same atomic ratio as that in which they were present in the scrap. This makes possible a joint recovery by simultaneous electrolysis, in which process the deposition product forms a master alloy which can be used, together with the precipitated rare earths which have been electrometallurgically reprocessed as misch metal, for the production of fresh hydrogen-storage alloys.