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An Efficient Leaching of Palladium from Spent Catalysts through Oxidation with Fe(III)

Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
Nuclear Chemistry and Industrial Material Recycling, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Gothenburg, Sweden
Authors to whom correspondence should be addressed.
Materials 2019, 12(8), 1205;
Received: 11 March 2019 / Revised: 5 April 2019 / Accepted: 11 April 2019 / Published: 12 April 2019
(This article belongs to the Special Issue Metallurgy of Non-Ferrous, Rare and Precious Metals)
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Reclamation of spent catalysts for the efficient recovery of palladium (Pd) is gaining growing attention due to its scarcity and high supply risk. Currently Pd extraction from spent catalysts through an efficient, economical, and green method has remained a challenge. In this study, Fe3+ is utilized for leaching through oxidation of Pd in a mild condition. Before leaching, distillation was proposed to remove and recover the organics from spent catalysts. The effects of HCl concentration, Fe3+ concentration, NaCl concentration, leaching time, and temperature on the leaching efficiency of Pd were investigated to determine the optimum leaching conditions. The results show that Pd extraction and dissolution of Al2O3 increase with higher HCl concentration. The effect of NaCl on Pd leaching efficiency is significant at low acid concentration (2.0 mol/L HCl). The leaching efficiency was 99.5% for Pd under the following conditions: 2.0 mol/L HCl, 4.0 mol/L NaCl, and 0.67 mol/L Fe3+ at 80 °C for 90 min. The leaching kinetics fits best to the shrinking-core model of surface chemical reaction. The activation energy for the leaching of Pd was 47.6 kJ/mol. PdCl42− was selectively adsorbed by anion exchange resin. The filtrate containing adequate H+, Cl-, and Fe3+ was reused as leaching agent. Pd leaching efficiency was over 96% after five cycle times. This study provides an efficient process for recovery of Pd from spent catalysts. View Full-Text
Keywords: spent catalysts; Palladium recovery; Fe3+ oxidative leaching; hydrometallurgy spent catalysts; Palladium recovery; Fe3+ oxidative leaching; hydrometallurgy

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Ding, Y.; Zheng, H.; Li, J.; Zhang, S.; Liu, B.; Ekberg, C. An Efficient Leaching of Palladium from Spent Catalysts through Oxidation with Fe(III). Materials 2019, 12, 1205.

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