Life Cycle Assessment of Neodymium-Iron-Boron Magnet-to-Magnet Recycling for Electric Vehicle Motors

• Published in: Environmental science & technology Vol. 52; no. 6; pp. 3796 - 3802
• Main Authors: Jin, Hongyue, Afiuny, Peter, Dove, Stephen, Furlan, Gojmir, Zakotnik, Miha, Yih, Yuehwern, Sutherland, John W
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 20.03.2018
• Subjects: Alternative energy; Alternative energy sources; annealing; Boron; Clean energy; coatings; ecological footprint; Ecological risk assessment; Electric vehicles; electricity; Electroplating; Energy sources; Environmental impact; Hydroelectric power; hydrogen; industry; Iron; Life cycle analysis; Life cycle assessment; Life cycle engineering; Life cycles; Magnetic fields; magnetic materials; milling; mixing; Motors; Neodymium; Nickel; Permanent magnets; Rare earth elements; Recycling; risk; Studies; uncertainty; wind; Faroe Islands
• ISSN: 0013-936X; 1520-5851; 1520-5851
• DOI: 10.1021/acs.est.7b05442

Neodymium-iron-boron (NdFeB) magnets offer the strongest magnetic field per unit volume, and thus, are widely used in clean energy applications such as electric vehicle motors. However, rare earth elements (REEs), which are the key materials for creating NdFeB magnets, have been subject to significant supply uncertainty in the past decade. NdFeB magnet-to-magnet recycling has recently emerged as a promising strategy to mitigate this supply risk. This paper assesses the environmental footprint of NdFeB magnet-to-magnet recycling by directly measuring the environmental inputs and outputs from relevant industries and compares the results with production from “virgin” materials, using life cycle assessments. It was found that magnet-to-magnet recycling lowers environmental impacts by 64–96%, depending on the specific impact categories under investigation. With magnet-to-magnet recycling, key processes that contribute 77–95% of the total impacts were identified to be (1) hydrogen mixing and milling (13–52%), (2) sintering and annealing (6–24%), and (3) electroplating (6–75%). The inputs from industrial sphere that play key roles in creating these impacts were electricity (24–93% of the total impact) and nickel (5–75%) for coating. Therefore, alternative energy sources such as wind and hydroelectric power are suggested to further reduce the overall environmental footprint of NdFeB magnet-to-magnet recycling.