| 摘要 |
<p>PROBLEM TO BE SOLVED: To efficiently recover a valuable material such as nickel, cobalt and rare earth metal even when impurity such as copper and iron is mixed in from a waste nickel.hydrogen secondary battery by a small quantity of industrial chemical to be used without practically causing a problem of corrosion of a device. SOLUTION: A used nickel.hydrogen secondary battery is crushed, cracked and sieved, and is separated into a coarse grain part containing plastic, iron, foaming nickel or the like and a fine grain part containing a nickel hydroxide and hydrogen storage alloy. After plastic and paper are removed from the coarse grain part after being sieved by magnetic separation, an organic substance such as remaining carbon is completely removed by combustion, and iron is removed by pulverization and sieving, and foaming nickel is recovered. Nickel and cobalt are melted from the fine grain part after being sieved by a sulfuric acid solution containing alkaline metal such as sodium and potassium, and rare earth metal such as cerium and lanthanum is separated as a deposit of sulfuric acid double salt with alkaline metal, and the rare earth metal is recovered. A sulfuric acid solution of cobalt is electrolyzed by adjusting pH of a cathode part to 4 or more, and nickel and cobalt are recovered as metal.</p> |
