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Recovery of Platinum and Palladium from Waste Catalysts of Petroleum Industry

Asadzadeh, Mojtaba | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 46340 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Sajadi, Ali Akbar; Matloubi Moghadam, Firouz
  7. Abstract:
  8. The petroleum industry is one of the technological applications which more platinum-group metals (PGM) employs. Therefore, the recovery of the PGMs from the waste catalysts of petroleum industry could be an important source to obtain these precious metals, with economic and environmental consequences.
    In this work, the recovery of platinum and palladium from petroleum catalysts has been studied using waste RG-582 and LD-265 catalysts. Both catalyst were characterized through XRF, XRD and AAS. Aqua regia used as a leaching agent and The effect of dissolution temperature and time, liquid/ solid ratio (L/S), size of particles and elimination of coke was investigated. Under optimized conditions leaching process has done with 98% efficiency.
    Recovery of platinum and palladium from leached solutions has done by adsorption process with activated carbon (AC) as an environmentally friendly manner. According to the results, the optimum operating conditions for platinum and palladium removal by activated carbon were temperature of solution 85 and 98℃, pH = 0.5 and 2, time of adsorption 180 and 150 min and adsorbent loading capacity = 18.75 mgpt/gAC and 12.5 mgpd/gAC respectively. The activated carbon containing Platinum and Palladium was decomposed by ignition to produce Platinum and Palladium powder with commercial purity of 94.13% and 96.05% respectively.
    In order to extra purification of leaching solutions, strongly anion exchanger resin (A) and slightly anion exchanger (B) were used. Through experiments the break through point of resin A and resin B for platinum and Palladium 121.6, 131.21, 14.87 and 21.35 mg/gresin was obtained respectively. Impurities such as aluminum, iron and etc. were selectively removed from the resins by elution with 3 mol.L-1 HCl. Platinum and Palladium was desorbed passing 1 mol.L-1 Na2S2O3 (pH=9) and 0.1 mol.L-1 thiourea respectively. Recovery of Platinum and Palladium from resin A has done with 97.88% and 98.06% efficiency
  9. Keywords:
  10. Activated Carbon ; Economic Evaluation ; Platinum Recovery ; Spent Catalyst ; Petroluem Industry ; Palladium Recovery

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