Dynamic life cycle assessment of NdFeB magnet production – case for carbon emission intensity

NdFeB magnets are critical to many clean energy applications, such as electric vehicles and wind turbines. However, neodymium and other rare earth (RE) elements used in NdFeB magnets carry considerable environmental burdens (including carbon footprint) owing to direct emissions as well as intense energy and chemical consumptions in all major process steps. The environmental impacts of REEs and NdFeB magnet production have recently been discussed in many lifecycle assessment (LCA) studies. These LCA studies are primarily static in nature, i.e., the lifecycle inventory (LCI) is compiled using the material and energy flows of existing processes and facilities. On the one hand, the RE industry is implementing many initiatives to reduce the environmental footprint; on the other hand, increasing demand has pushed the industry to keep exploring low-grade or unconventional ores that require higher energy and material utilization for processing. As manufacturers of clean energy technologies strive to build a green supply chain, predicting the environmental impacts of NdFeB magnets under different scenarios has become an essential task. The present study explores a dynamic LCA (DLCA) with a focus on the carbon footprint given the declining ore grade, best available (control) technology, recycling rate, RE ore type/origin/processing pathways, and environmental policy implementations. We used the Python-based tool Brightway2/Temporalis for the DLCA. The dynamic LCI was compiled from the critical material LCA tool as well as plans and policies from a Chinese REE company, various national governments, and potential REE mining projects worldwide. The scenario analysis is considered sustainable, moderate, and business as usual. The results show that 90% of the contributions to greenhouse gas emissions were from the RE metals used and that the environmental burden could be significantly decreased by implementing a higher magnet recycling rate and utilizing RE metals from low-carbon pathways, e.g., Mount Weld in Australia. The DLCA of the NdFeB magnet production process reveals trends regarding the environmental impacts of RE magnets, thereby providing a clear policy strategy to achieve the sustainability goals for stakeholders.