Process development and optimization for platinum recovery from PEM fuel cell catalyst

This paper presents the development of an efficient hydrometallurgical recovery process of platinum from Pt catalyst of PEMFC electrodes at laboratory scale, whereby leaching, Pt separation, precipitation and filtration steps were combined in order to optimize the recovery process. The efficiencies of two different leaching agents (H2O2/HCl and HNO3/HCl) and two different separation methods (liquid–liquid extraction and ion exchange resins) were compared in this study. Finally the platinum was recovered by precipitation as ammonium hexachloroplatinate (NH4)2PtCl6 (a PEMFC catalyst precursor) at the outlet of each process alternative. Thus four different process alternatives were tested and compared. At first the experiments were performed with Pt/C particles and hexachloroplatinic acid in order to study the influence of several experimental parameters on platinum recovery efficiency. Then the real PEMFC catalyst coated membranes (CCMs) were treated according to the optimized leaching/recovery process. Finally, the most efficient process alternative gave a 76% Pt recovery yield from CCMs.