METHOD FOR RECOVERING VALUABLE METALS FROM WASTE NICKEL-HYDROGEN BATTERY

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PROBLEM TO BE SOLVED : To provide a method for recovering valuable metals from a waste nickel-hydrogen battery, which, by establishing a process which bypasses a nickel smelting process, enables further improvement of safety and prevention of contamination of zinc and yttrium in the final product while trying to reduce the cost of the process in general. SOLUTION : In a solvent extraction step S13, a solution from which rare earth elements have been removed is subjected to a solvent extraction treatment by a phosphoric acid-based extraction agent and, after removing zinc and yttrium completely from the solution from which rare earth elements have been removed, an extraction residual liquid containing nickel and cobalt is subjected to an oxidation-neutralization treatment. At which time, in a back-extraction step S14, an organic solvent after the extraction is back-extracted with a sulfuric acid solution to obtain a back-extraction liquid containing zinc and yttrium, and thereafter in a neutralization step S15, the back-extraction liquid is neutralized with an alkali solution to recover zinc and yttrium as a mixed hydroxide precipitate. SELECTED DRAWING : Figure 1 COPYRIGHT : (C)2016, JPO&INPIT