Uncovering the features of rhodium metabolism in China during 2011–2022

Rhodium has unique properties, such as high-temperature oxidation resistance and catalytic activity, making it irreplaceable in various domains such as automobile exhaust purification and chemical production. Given its pivotal role in facilitating China's green and low-carbon transition and the advancement of high-tech industries, rhodium has become a strategic resource. However, China heavily relies on importing rhodium to meet its domestic demand due to its limited rhodium reserve. This study employs dynamic material flow analysis (DMFA) to trace the rhodium flows throughout its entire life cycle in China for the period of 2011–2022 so that the key features of rhodium metabolism can be uncovered, including rhodium production, consumption, trade, in-use stock, and recycling. Our results show that the domestic demand for rhodium increased by 2.18 times during this study period. The cumulative rhodium consumption reached 82,890 kg, of which automobile three-way catalysts (TWCs) accounted for 71.85% of the total rhodium consumption, followed by the chemical sector (13.64%) and the glass sector (8.95%). China's accumulative imported rhodium reached 77,447 kg, meaning an import reliance rate (IRR) of 91.81%. The total recycled rhodium reached 21,184 kg, meaning a recycling rate (RR) of 58.63%. These findings reflect that China is facing several challenges in achieving sustainable rhodium resource management, such as a significant supply risk, and inadequate recycling. Consequently, China should establish a comprehensive rhodium recycling system and diversify its rhodium supply both domestically and internationally to ensure the sustainable supply of rhodium resources.