| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for recovering hydrogen storage alloy constituent elements, particularly, rare earth metals or the like from valuable metal-containing waste material such as a waste nickel-hydrogen secondary battery in a high yield. <P>SOLUTION: When a recovered matter recovered from a waste nickel-hydrogen secondary battery and mainly made up of a negative electrode is subjected to heating treatment in a gaseous hydrogen atmosphere so as to be decarburized, easily oxidizable rare earth elements are oxidized to reduce the recovery ratio thereof. Thus, hydroxide such as nickel hydroxide oxidizing rare earth elements is beforehand subjected to heating treatment in a reducing atmosphere so as to be reduced, thereafter, heating is performed in a nonoxidizing atmosphere to remove carbon, so that the oxidation of rare earth elements is prevented to increase the recovery ratio thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
