| 摘要 |
<p>PROBLEM TO BE SOLVED: To easily recover valuable metals in a negative pole at a low cost by treating a negative pole alloy of a waste secondary cell of nickel hydrogen- storing alloy by the combination of an arc fusing method and a fused-salt electrolysis method. SOLUTION: An alloy powder recovered from a negative pole of a waste nickel hydrogen-storing alloy secondary cell is press formed and fused as the consumable electrode of arc discharge to form an alloy layer and a slug layer. The alloy layer essentially consists of Ni, Co, etc., and contains light rare earth elements so that it can be used as it is as an alloy for a nickel hydrogen-storing secondary cell. The slug layer essentially consists of oxides of light rare earth elements and contains a small amt. of Ni and Co. Therefore, the slug is electrolyzed and reduced by using an electrolytic bath containing, by mass %, 50-90% light rare earth fluorides, 0-50 % lithium fluoride, 0-50% barium fluoride and 0-30% calcium fluoride, a carbon electrode as an anode and Ni or Co as a cathode which is the structural component of an hydrogenstoring alloy for a cell. Thus, not only light rare earth elements but valuable metals such as Ni and Co are recovered.</p> |
