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利用Nd-Fe-B 油泥回收制备高性能烧结磁体的有效方法
Xiaowen Yin, Ming Yue, Qingmei Lu, Min Liu, Feng Wang, Yubing Qiu, Weiqiang Liu, Tieyong Zuo, Shanshun Zha, Xuliang Li, Xiaofei Yi
工程（英文） ›› 2020, Vol. 6 ›› Issue (2) : 165-172.
PDF(2265 KB)
PDF(2265 KB)
利用Nd-Fe-B 油泥回收制备高性能烧结磁体的有效方法
An Efficient Process for Recycling Nd–Fe–B Sludge as High-Performance Sintered Magnets
全球稀土储量的下降以及当前湿法回收技术对环境造成的影响日益受到人们的关注，开发一种有效回收钕铁硼（Nd-Fe-B）烧结磁体生产过程中剩余油泥的技术已迫在眉睫。本研究选择了Nd-Fe-B烧结磁体加工过程中产生的无心磨削油泥作为原材料。我们对油泥进行了还原扩散（RD）处理，以合成可供回收的钕磁体（Nd2Fe14B）粉末。在此过程中，包括钕（Nd）、镨（Pr）、钆（Gd）、镝（Dy）、钬（Ho）和钴（Co）在内的大多数有价值的元素被同时回收。氯化钙粉末（CaCl2）具有较低的熔点，我们将其引入RD工艺中以降低回收成本和提高回收效率。通过调节反应温度和油泥中的钙含量，我们系统地研究了Nd-Fe-B油泥回收过程中的反应机理。结果表明，当油泥中的钙含量为40 wt%且反应温度为1050 ℃时，获得的Nd2Fe14B单相颗粒的结晶度良好。我们在回收的Nd2Fe14B颗粒中掺杂了含量为37.7 wt%的Nd4Fe14B粉末，用以制备Nd-Fe-B烧结磁体，且所获磁体的剩磁为12.1 kG（1G =1×10–4 T）、矫顽力为14.6 kOe（1 Oe = 79.5775 A·m–1）、磁能积为34.5 MGOe。该回收路径在回收效率和成本上具有很大的优势。
Given the increasing concern regarding the global decline in rare earth reserves and the environmental burden from current wet-process recycling techniques, it is urgent to develop an efficient recycling technique for leftover sludge from the manufacturing process of neodymium-iron-boron (Nd–Fe–B) sintered magnets. In the present study, centerless grinding sludge from the Nd–Fe–B sintered magnet machining process was selected as the starting material. The sludge was subjected to a reduction-diffusion (RD) process in order to synthesize recycled neodymium magnet (Nd2Fe14B) powder; during this process, most of the valuable elements, including neodymium (Nd), praseodymium (Pr), gadolinium (Gd), dysprosium (Dy), holmium (Ho), and cobalt (Co), were recovered simultaneously. Calcium chloride (CaCl2) powder with a lower melting point was introduced into the RD process to reduce recycling cost and improve recycling efficiency. The mechanism of the reactions was investigated systematically by adjusting the reaction temperature and calcium/sludge weight ratio. It was found that single-phase Nd2Fe14B particles with good crystallinity were obtained when the calcium weight ratio (calcium/sludge) and reaction temperature were 40 wt% and 1050 °C, respectively. The recovered Nd2Fe14B particles were blended with 37.7 wt% Nd4Fe14B powder to fabricate Nd–Fe–B sintered magnets with a remanence of 12.1 kG, and a coercivity of 14.6 kOe, resulting in an energy product of 34.5 MGOe. This recycling route promises a great advantage in recycling efficiency as well as in cost.
Nd-Fe-B磨削油泥 / 再生烧结磁体 / 钙还原扩散 富稀土合金掺杂 /
Nd–Fe–B grinding sludge Recycled sintered magnets / Calcium reduction-diffusion / Rare-earth-rich alloy doping
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