EARTH

[1901-09-09] Pressure Oxidative Leaching of Spent Automobile Catalysts: Leaching Behavior of Platinum Group Metals

○Altansukh Batnasan¹, Kazutoshi Haga¹, Atsushi Shibayama¹ (1. Akita University)

Chairman：Naoki Hiroyoshi（Hokkaido University）

Keywords:Platinum group metals, automobile catalyst, pressure oxidation, leaching, hydrochloric acid

Platinum group metals (PGM) are precious and technologically important metals which play significant roles in a variety of applications, including catalytic converters, electronics, dental and medical devices, glass industry, and electrical and electrochemical industry. However, natural abundance of PGM in the earth’s crust is extremely scarce in comparison to other precious metals. Therefore, an effective recycling of spent critical materials containing PGM such as catalysts, electronic and electric devices, and equipment is essential to meet future demand and a stable supply of these metals. Recovery of the PGM from these materials has some serious impacts on the environment due to the thermal treatment and the use of concentrated acids. This research aims to investigate the leaching behavior of platinum group metals from spent automobile catalysts in low concentrations of hydrochloric acid under the oxidizing conditions with oxygen addition in an autoclave. Leaching parameters including hydrochloric acid concentration (0.05–1 M), temperature (25–120 °C), pressure in an autoclave (0.4–1.6 MPa), that affect the PGM dissolution were investigated in detail. Results showed that the achieved maximum leaching efficiency for Pt, Pd and Rh was as 91 %, 11.3 % and 20.6 %, respectively under the optimum conditions determined through this study.