Institute of Energy and Climate Research, Systems Analysis and Technology Evaluation (IEK-STE), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich D-52425, Germany.
Sci Total Environ. 2021 Oct 15;791:148257. doi: 10.1016/j.scitotenv.2021.148257. Epub 2021 Jun 3.
Rare earth elements (REEs) are one of the most important elements used for transformation of the fossil era into a decarbonized future. REEs are essential for wind, electric and hybrid vehicles, and low-energy lighting. However, there is a general understanding that REEs come along with multiple environmental problems during their extraction and processing. Life cycle assessment (LCA) is a well-established method for a holistic evaluation of environmental effects of a product system considering the entire life cycle. This paper reviews LCA studies for determining the environmental impacts of rare earth oxide (REO) production from Bayan Obo and ion adsorption clays (IAC) in China, and shows why some studies lead to over- and underestimated results. We found out that current LCA studies of REE production provide a good overall understanding of the underlying process chains, which are mainly located in China. However, life cycle inventories (LCI) appear often not complete. Several lack accuracy, consistency, or transparency. Hence, resulting environmental impacts are subject to great uncertainty. This applies in particular to radioactivity and the handling of wastewater and slurry in tailing ponds, which have often been neglected. This article reviews 35 studies to identify suitable LCAs for comparison. The assessment covers the world's largest REO production facility, located in Bayan Obo, as well as in-situ leaching of IACs in the Southern Provinces of China. A total of 12 studies are selected, 8 for Bayan Obo and IACs each. The LCIs of these studies are reviewed in detail. The effects of over- and underestimated LCIs on the life cycle impact assessment (LCIA) are investigated. The partly controversial results of existing LCAs are analyzed thoroughly and discussed. Our results show that an increased consistency in LCA studies on REO production is needed.
稀土元素（REEs）是将化石时代转变为脱碳未来的最重要元素之一。 REEs 对于风力、电动和混合动力汽车以及低能耗照明至关重要。然而，人们普遍认为，在提取和加工 REEs 时会伴随多种环境问题。生命周期评估（LCA）是一种成熟的方法，可用于综合评估考虑整个生命周期的产品系统的环境影响。本文回顾了用于确定中国白云鄂博和离子吸附粘土（IAC）中稀土氧化物（REO）生产的环境影响的 LCA 研究，并展示了为什么某些研究导致结果过高或过低估计。我们发现，当前的 REE 生产 LCA 研究为了解基本的过程链提供了很好的总体认识，这些过程链主要位于中国。但是，生命周期清单（LCI）似乎并不完整。 一些缺乏准确性、一致性或透明度。因此，产生的环境影响存在很大的不确定性。这尤其适用于放射性以及尾矿池中的废水和泥浆的处理，这些问题经常被忽视。本文综述了 35 项研究，以确定可用于比较的合适 LCA。评估涵盖了位于白云鄂博的世界上最大的 REO 生产设施，以及中国南方省份的原地浸出 IAC。共选择了 12 项研究，其中 8 项用于白云鄂博和 IAC。详细审查了这些研究的 LCI。研究了过高和过低估计 LCI 对生命周期影响评估（LCIA）的影响。彻底分析和讨论了现有 LCA 中存在的部分有争议的结果。我们的结果表明，需要在 REE 生产的 LCA 研究中提高一致性。
