In Situ Mechanochemical Treatment of the Fe–Si–PGMs Alloy for Enhanced Platinum Group Metal Recovery: Overcoming Thermodynamic and Kinetic Barriers

Abstract

The recovery of platinum group metals (PGMs) from spent automotive catalysts has promoted the development of energy and the environment, but the challenges of PGMs recycling are enormous. Herein, we present an in situ mechanochemical leaching process for the extraction of PGMs from the Fe−Si− PGMs alloy. A recovery scheme was designed based on the study of alloy properties, and we demonstrated that under high-speed ball milling conditions, a sustainable HCl + FeCl 3 + H 2 O 2 solution can achieve extraction rates of 99, 98, and 96% for Pd, Pt, and Rh, respectively. Compared with the traditional aqua regia leaching, the proposed method achieves extraction rate improvements of 11% for PGMs without producing harmful NO x chemicals. Studies revealed that mechanochemical leaching overcame thermodynamic obstacles and kinetic retardation. We developed a sustainable and highly effective method for extracting PGMs in Fe−Si−PGMs alloy, which advances the progress in resource utilization and offers a promising approach for other difficult-to-treat PGM-containing materials.