| 摘要 |
PURPOSE:To efficiently recover noble metal by immersing a metallic carrier catalyst in which a fire resistant inorg, oxide catalyst layer containing noble metal is formed on a metallic carrier base material in sulfuric acid or phosphoric acid each having a prescribed concn. and heating to dissolve the catalyst layer. CONSTITUTION:The catalyst layer of the fire resistant inorg, oxide (e.g. activated alumina) containing noble metal (e.g. platinum) is formed on the metallic carrier base material (e.g. stainless steel) to produce the metallic carrier catalyst for purifying a waste gas exhausted from an internal combustion engine of an automobile, etc..Then, at the time of recovering the noble metal from a used metallic carrier catalyst, at first, the catalyst is immersed in a soln, of >=30vol.% sulfuric acid and/or phosphoric acid, and the metallic carrier catalyst is separated into the metallic carrier base material and the catalyst layer by heating to dissolve the catalyst layer of the metallic carrier catalyst. Then, the noble metal is recovered from a dissolved soln. and an undissolved residue by using a conventional method. |
