关键稀土元素之全球物质流网络的构建与结构演化分析

当今世界对发展高新技术至关重要的稀土资源有90%多产自中国。定量分析稀土元素的来源和去向以及如何在全球贸易网络中被输送到全世界兼具学术与政策意义。本项目将以钕、镝和钇三种对清洁能源技术至关重要且难以替代的关键稀土元素为对象，以1990-2015年为时间边界开展如下研究：（1）建立稀土元素的全生命周期流量与存量研究框架，模拟中国、美国和日本等世界主要经济体中关键稀土元素的动态流量与存量，分析这些经济体中关键稀土元素生产、使用、贸易以及循环利用的历史演化特征；（2）构建全球5大洲超过150个国家或地区之间关键稀土元素以粗矿、精矿、初级产品（氧化物和金属）、中间产品、最终产品、报废产品和废料等不同形态进行贸易的全球物质流网络，分析网络的结构、相互关联及其动态演化特征，解析网络动态演化的驱动因素和机制。研究结果将为我国制定有关优化稀土贸易结构和促进稀土资源可持续利用的政策提供数据基础和决策依据。

Many emerging technologies rely on the use of rare earth elements (REEs), of which more than 90% are now mined in China. It is therefore critical to quantitatively characterize the anthropogenic life cycles of REEs in China and other major economies such as Japan, U.S., and European Union. It is also important to know how China’s REEs are transported and processed at the global scale through an increasingly complex global trade system. We thus propose to examine three critical REEs (i.e., neodymium, dysprosium, and yttrium) which are predominately produced in China but are used globally as necessaries in a variety of clean energy technologies. In particular, this project will: (1) develop an anthropogenic life cycle framework for each REE for modeling their dynamic anthropogenic stocks and flows in major economies such as China, the US, Japan, and European Union during 1990-2015; (2) develop dynamic global material flow networks for each REE, covering more than 150 countries/territories during 1990-2015 and the trade of each REE in different forms including ores, concentrates, refined products, semis, final products, end-of-life products, and scrap; (3) analyze the evolution of the structure of these material flow networks using complex network analysis methods, and examine the factors and mechanisms driving the evolution of these material flow networks in the study period; and finally (4) explore policies that can help improve the sustainability and security of REEs production, use, and trade in China.