Recovery of Platinum from Spent Reforming Catalyst by Acid Leaching and Coprecipitation

Platinum content in a spent reforming catalyst were extracted by oxalic acid at temperatureup to 80°C.Pt extraction was increased by increasing the reaction time. The presence of coke covering did not effect on the spent catalyst. According to previous study, after the dissolution with oxalic acid, platinum in the leachate exist as ionic form such as [PtCl6]4- and [PtCl4]2.Fe(II) solution were added to the leachate containing Pt to be a molar ratio of 1/10 [Pt(IV)/Fe(II)] .The solution was adjusted to the pH 6 with NaOH solution to precipitate iron hydroxide.Only about 20% of platinum was coprecipitated with Fe(II) hydroxide after 30 min.These are different from the result of model experiment, and we discussed the problem and the solution toward practical recovery of Pt from the spent catalyst.