Simulation-Based Exergetic Analysis of NdFeB Permanent Magnet Production to Understand Large Systems

Abstract

Metallurgical simulation and evaluation of the resource efficiency of whole production processes are of key importance for sound environmental impact assessments. Exergy dissipation analysis is suitable to quantify the theoretical limits of a process and pinpoint hotspots for improvements along the value chain. Production of NdFeB permanent magnets is evaluated herein using a simulation-based life cycle assessment and exergetic analysis, including 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, which are applied in several low-carbon technologies. The maximum exergy efficiency of 60.7% shows that there is a limit on sustainability, which could however be improved via technological improvements and recovery of waste streams, revealing the inconvenient truth that the resource efficiency will never reach 100%.