| 摘要 |
<p>PURPOSE:To easily leach and recover noble metals from a substance contg. noble metals without using a strong acid such as aqua regia by treating the substance with an aqueous HCl soln. in the presence of nitrogen oxide as a catalyst in a vessel isolated from the air. CONSTITUTION:A precipitate produced by the electrolysis of copper or a purified precipitate such as a pretreated waste catalyst is pulped with an aqueous HCl soln. contg. optionally a metallic chloride such as NaCl, and the resulting pulp is charged into a reaction vessel 1 isolated from the air. Gaseous oxygen is substituted for the vapor phase in the vessel 1, the vessel 1 is kept at a prescribed temp., and a substance contg. NOx such as NaNO2 and one or more kinds of bi-quatervalent metals is added as an oxidation catalyst from a hole 5. A reaction is caused by stirring with a stirrer 7 to transfer noble metals such as Au, Pt and Pd from the precipitate to the soln. By this method, leaching is completed in a short time.</p> |
