Short-process method for preparing sintered NdFeB magnets with high magnetic properties recycling from NdFeB sludge
US9728310B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Apr 19, 2016 |
| Grant date | Aug 8, 2017 |
| Priority date | — |
| Expiry date | Apr 19, 2036 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB22F2998/10
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention discloses a short process preparation technology of sintered NdFeB magnets from the NdFeB sludge, which relates to a field of recycle technology of NdFeB sludge. The present invention comprises the following steps: water bath distillation of organics in sludge, ultrasonic cleaning, calcium reduction and diffusion, ultrasonic rinsing in a magnetic field and drying, powders mixing and sintering. NdFeB sludge as raw materials was directly prepared from recycled sintered magnets with high magnetic properties. Most of the organics in the sludge could be removed by a vacuum distillation process with stepwise heating. The ultrasonic rinsing process in a magnetic field could effectively remove the remaining organics. The recycled sintered magnets exhibited good maximum energy product [(BH)max] of 35.26 MGOe. The present invention has important features, such as the short processing time, efficient environmental protection, high recycling rate and effective utilization rate of rare earth metals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.