Patent ID: 6835228
Filing Date: 2004-12-28
Classification: C22B,H01M,Y02E,Y02P,Y02W

Abstract:
A process for recovering valuable metals from waste secondary batteries comprising lithium ion batteries, Niâ€”H batteries and Niâ€”Cd batteries, wherein said waste secondary batteries are calcined and sieved to generate an ash containing metals and metal oxides, said process comprising the following steps:a) dissolving said ash with a 2N-6N sulfuric acid aqueous solution; b) adding an alkali to the resulting solution from step a) so that cadmium (Cd) ions and rare earth metal ions contained in the solution precipitate; c) performing a solid/liquid separation on the resulting mixture from step b); d) extracting the resulting solution from the separation in step c) with a first organic extractant to form an aqueous layer containing nickel (Ni) ions and cobalt (Co) ions and an organic layer rich in Cd, iron (Fe) and zinc (Zn) ions; e) extracting the aqueous layer from step d) with a second organic extractant to form an organic layer rich in Co ions and an aqueous layer rich in Ni ions; f) counter extracting the organic layer rich in Co ions from step e) with a sulfuric acid aqueous solution to obtain an aqueous layer rich in Co ions; g) using the aqueous layer rich in Ni ions formed in step e) as an electrolysis solution, and using a voltage of 1.5-4.0 volts to perform an electrolysis, thereby forming by reduction a Ni metal on a cathode in said electrolysis; h) using the aqueous layer rich in Co ions formed in step f) as an electrolysis solution, and using a voltage of 1.5-4.0 volts to perform an electrolysis, thereby forming by reduction a Co metal on a cathode in said electrolysis; i) adding a water soluble carbonate to a residue solution after the electrolysis in step g), thereby forming a precipitation of lithium carbonate.