A simulation-based exergetic analysis of NdFeB permanent magnet production to understand large systems

Metallurgical simulation and evaluation of the resource efficiency of whole production processes are of key importance for a sound environmental impact assessment. An exergy dissipation analysis is suitable for quantifying the theoretical limits for a process and pinpoint hotspots for improvement along the value chain. The production of NdFeB permanent magnets is evaluated through a simulation-based life cycle assessment and exergetic analysis, comprising 107 unit operations, 361 flows and 209 compounds. This methodology highlights areas with the greatest potential for improvements in terms of technology and environmental impact, shedding light on the true resource efficiency and minimum exergy dissipation for the production of permanent magnets, present in several low-carbon technologies. A maximum exergy efficiency of 60.7% shows that there is a limit for sustainability, which can be improved by technological improvements and recovery of waste streams, showing the inconvenient truth that the resource efficiency will never reach 100%.