Anthropogenic cycles of praseodymium in China: 2000–2020

Abstract

Praseodymium (Pr) is one of critical rare earth elements (REEs), which is widely used in clean energy technologies and home appliances. With the increasing demand of renewable energy, it is necessary to uncover the features of Pr stocks and flows through its whole life cycle. China is the largest REEs supplier in the world, but its Pr stocks and flows remain unclear. Therefore, this study investigates the anthropogenic Pr cycle in China for the period of 2000–2020 by applying dynamic material flow analysis. The results show that a total of 176 Gg Pr flowed into the Chinese anthropogenic system over the past two decades. Pr supply reached 10.8 Gg in 2020, while Pr demand reached 9.2 Gg in 2020, respectively. The top three Pr consumption fields were wind turbines (2.5 Gg), refrigerators (431 Mg), and electric vehicles (403 Mg) in 2020, with annual growth rates of 40%, 32%, and 86% during the study period, respectively. The largest in-use Pr stock came from wind turbines (with a figure of 18.8 Gg) in 2020, followed by air conditioners (5.5 Gg) and wash machines (3.2 Gg). The largest end-of-life flow came from air conditioners in 2020, with a figure of 847 Mg. Based on these results, three policy recommendations are proposed, including stable Pr supply, appropriate Pr recycling and recovery, and synergetic management with neodymium.