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<p>NdFeB scrap is an important secondary source of rare earth elements (REEs) and other valuable elements. This study investigated the recovery of the REEs and high-value utilization of the by-products. Following an evaluation based on thermodynamic theory, a selective chlorination method using anhydrous FeCl<sub>2</sub> under normal atmospheric pressure within an argon protective atmosphere was proposed. Subsequently, the effects of roasting temperature, process time, and anhydrous FeCl<sub>2</sub> dosage on the total rare earth oxide (TREO) leaching rate were investigated in detail, in combination with thermogravimetric-differential thermal analysis (TG–DTA), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the highest TREO leaching rate of 98.54% was obtained under roasting conditions of 620&#xa0;°C for 60&#xa0;min when doped with 1.05 times the theoretical amount of anhydrous FeCl<sub>2</sub> required. Additionally, secondary chlorination processes using AlCl<sub>3</sub> and BCl<sub>3</sub> were proved to be ineffective. However, the necessity of dehydration for use of FeCl<sub>2</sub> was confirmed. Otherwise, a water-insoluble oxychloride was formed via a reaction with water that seriously reduced the TREO leaching rate. Under the optimal selective chlorination conditions, the by-product consisted mainly of Fe, which presented excellent adsorption properties in the 2 − 18&#xa0;GHz frequency bandwidth, possibly because of its uniform pores.</p>

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Rare Earth Recovery from NdFeB Scrap by Selective Chlorination using FeCl2 and Microwave Absorption Evaluation of by-Products

  • 期刊论文

  • 发表日期：

    2026年5月8日

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  • Yongchun Deng,
  • Shuai Yan,
  • Wenbin Xin,
  • Jing Zhang,
  • Xiangfan Wang,
  • Ziyan Gao,
  • Yinju Jiang

摘要

NdFeB scrap is an important secondary source of rare earth elements (REEs) and other valuable elements. This study investigated the recovery of the REEs and high-value utilization of the by-products. Following an evaluation based on thermodynamic theory, a selective chlorination method using anhydrous FeCl2 under normal atmospheric pressure within an argon protective atmosphere was proposed. Subsequently, the effects of roasting temperature, process time, and anhydrous FeCl2 dosage on the total rare earth oxide (TREO) leaching rate were investigated in detail, in combination with thermogravimetric-differential thermal analysis (TG–DTA), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the highest TREO leaching rate of 98.54% was obtained under roasting conditions of 620 °C for 60 min when doped with 1.05 times the theoretical amount of anhydrous FeCl2 required. Additionally, secondary chlorination processes using AlCl3 and BCl3 were proved to be ineffective. However, the necessity of dehydration for use of FeCl2 was confirmed. Otherwise, a water-insoluble oxychloride was formed via a reaction with water that seriously reduced the TREO leaching rate. Under the optimal selective chlorination conditions, the by-product consisted mainly of Fe, which presented excellent adsorption properties in the 2 − 18 GHz frequency bandwidth, possibly because of its uniform pores.