Recovery of Platinum from Spent Petroleum Catalysts by a Hydrometallurgical Method

Platinum was recovered from the leaching solution of spent petroleum catalysts by solvent extraction. The spent catalysts were first roasted at 800 degrees C to eliminate volatile matter. Most of the platinum in the spent catalysts was dissolved at an optimum leaching condition in a mixture of HCl and H2O2. Separation of platinum from the leaching solution was accomplished by solvent extraction with Aliquat 336 after iron was removed by extraction with TBP. Platinum and iron were stripped from the loaded Aliquat 336 and TBP by using 1 M HClO4 and 0.1 M HCl, respectively. Finally, HCl in the raffinate was recovered by extraction with TEHA and then by stripping with water. The optimum conditions to dissolve platinum and to separate platinum by solvent extraction are reported together with the mass balance of the constituents of the spent catalysts in each step.