Urban Mining Company, Perryville, Maryland 21903, USA
Abstract:
Recycling of NdFeB-type sintered magnets has received a great deal of attention over the past fifteen years. The demand for recycled NdFeB sintered magnets is growing together with the need for NdFeB magnets in an increased diversity of high temperature applications, such as electrical machines for transportation. The NdFeB magnets used in these applications need to operate at temperatures in excess of 100 oC. For this reason, the use of scarce and expensive heavy rare earths, like Dy or Tb, in the NdFeB magnets for the motors of the next-generation vehicles is inevitable.
In our study, waste NdFeB-type sintered magnets were acquired and subjected to a recycling method that is energetically more favorable than the traditional magnet-manufacturing route. By carefully controlling the processing parameters, we were able to produce various recycled NdFeB-type sintered magnets suitable for high temperature applications. Furthermore, aiming to decrease the Dy content, we succeeded in producing recycled magnets that yielded lower Dy when compared to commercial magnets sharing similar magnetic performances. The overall rare earth content of the recycled magnets was 14.15 at.%. Moreover, 97 at.% of waste material was used, and hence recovered, in the recycling process.
In our study, waste NdFeB-type sintered magnets were acquired and subjected to a recycling method that is energetically more favorable than the traditional magnet-manufacturing route. By carefully controlling the processing parameters, we were able to produce various recycled NdFeB-type sintered magnets suitable for high temperature applications. Furthermore, aiming to decrease the Dy content, we succeeded in producing recycled magnets that yielded lower Dy when compared to commercial magnets sharing similar magnetic performances. The overall rare earth content of the recycled magnets was 14.15 at.%. Moreover, 97 at.% of waste material was used, and hence recovered, in the recycling process.