Recently, recycling of severely contaminated Nd–Fe–B sintered magnets sludge had drawn considerable attention due to the concern of environmental burden and high cost of traditional wet process recycling. In the present study, we describe a new technology that utilizes distillation, reduction–diffusion (RD), and nanoparticle-doping techniques to prepare recycled Nd–Fe–B sintered magnets from Nd–Fe–B sludge in an efficient and environmentally friendly way. The sludge was purged first to remove both organic impurities and nonmagnetic impurities. The purged products were then treated with calcium-assisted RD reaction to obtain Nd₂Fe₁₄B single-crystalline powders. After doping with NdH_x or DyH_x nanoparticles, the powders were fabricated into recycled Nd–Fe–B sintered magnets by the conventional sintering method. The recycled magnets bear comparable magnetic properties to the original magnets. With 10% doping of NdH_x, the energy product of the original magnets is recovered by 88%; with 15% doping of DyH_x, the coercivity of the recycled magnets increases by 34% compared to the original magnets. Furthermore, comparison between the conventional recycling method and our new technology demonstrates that our new technology is an economical and environmentally friendly strategy for sintered Nd–Fe–B sludge recycling.

中文翻译：

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通过还原扩散途径回收Nd-Fe-B烧结磁体污泥以生产具有高能量密度的烧结磁体

最近，由于对环境负担和传统湿法循环利用的高昂成本的关注，严重污染的Nd-Fe-B烧结磁铁污泥的循环利用引起了人们的极大关注。在本研究中，我们描述了一种新技术，该技术利用蒸馏，还原扩散（RD）和纳米颗粒掺杂技术以高效，环境友好的方式从钕铁硼污泥制备回收的钕铁硼烧结磁体。 。首先清除污泥，以去除有机杂质和非磁性杂质。然后将吹扫的产物用钙辅助的RD反应处理以获得Nd ₂ Fe ₁₄ B单晶粉末。用NdH _x或DyH _x掺杂后用常规的烧结方法将纳米颗粒制成可回收的Nd-Fe-B烧结磁体。回收的磁体具有与原始磁体相当的磁性能。通过掺入10％的NdH _x，原始磁体的能量积可回收88％。掺杂15％的DyH _x，与原始磁体相比，回收磁体的矫顽力提高了34％。此外，将传统的回收方法与我们的新技术进行比较表明，我们的新技术是烧结Nd-Fe-B污泥回收的一种经济，环保的策略。