| 摘要 |
<p>PURPOSE:To recover platinum group metals without damaging a electrode base material by dissolving Pt and Ir by acid water solution after reduction treatment to the platinum group metallic oxide on the electrode, further dipping the electrode into mixed acid and dissolving remained metal and binder. CONSTITUTION:In the electrode, on which electrode active material containing platinum group metallic oxides of Pt, Ir and Ru is coated, at first, by using reducing agent, the metallic oxides are reduced to come to the metal-state. Next, the electrode is treated by the water solution containing hydrochloric acid and nitric acid, and a large part of Pt and a part of Ir are dissolved. Successively, this electrode is dipped into the mixed acid containing at least nitric acid or sulfuric acid and hydrofluoric acid, and the binder of titanium oxide, etc., the remained Ir, Ru and a little quantity of Pt are peeled and recovered. By this method, the platinum group metals can be recovered without damaging the electrode.</p> |
