| 摘要 |
PROBLEM TO BE SOLVED: To recover Pd with high efficiency from waste liquid such as waste liquid containing Pd in a low concentration, which is obtained in the process of washing Pd-plated matters, or the like, by bringing the Pd-containing liquid into contact with a cation exchanger. SOLUTION: Waste water used for washing, which is discharged from the Pd-plating process for electronic parts or the like, is cited as the suitable solution containing Pd, especially, the solution containing Pd in an amount of <=100 mg/L is suitably applied to the recovery process. The waste liquid 1 obtained in Pd-plating process is stored in a cushion tank 2, and is sent to an ion exchange resin tower 6 through a pump 4 and a filter 5. In the tower 6, Pd is adsorbed and the waste liquid is sent to a waste water treating apparatus 7. The suitable cation exchange resins to be filled into the ion exchange tower 6 are gel-type strongly acidic resins and porous-type strongly acidic resins. Elution of Pd from the cation exchange resin to which Pd is adsorbed is preferably carried out by using a solution containing Cl ion, such as HCl, When an aqueous HCl solution is used as an eluent, the suitable concentration of HCl is in the range of 3.5-5.5 mol/L.
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