Recycle of rare earth sintered magnet powder scraps as electromagnetic wave absorbers in gigahertz range

Itoh, Masahiro; Nishiyama, Keizo; Shogano, Fumiyoshi; Murota, Tadatoshi; Yamamoto, Kazuhiko; Sasada, Masaaki; Machida, Ken‐ichi

doi:10.1016/j.jallcom.2007.04.093

Cited by 19 publications

(8 citation statements)

References 12 publications

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“…Recently, Japanese companies and South Korean research institutions have made a variety of technological developments. [58,59] Machida and coworkers [28,[60][61][62][63] multifariously investigated a process in which magnet scrap is cascaderecycled (down-grade recycling). Although this method is advantageous for the efficient use of magnet scrap without consuming high amounts of energy, it can be difficult to balance the amount of generated scrap and the expected specification for cascade-recycled products with the actual demand.…”

Section: Basic Research On Pyrometallur-gical Recycling Technologmentioning

confidence: 99%

Current Status on Resource and Recycling Technology for Rare Earths

Takeda

Okabe

2014

Metallurgical and Materials Transactions E

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The development of recycling technologies for rare earths is essential for resource security and supply stability because high-quality rare earth mines are concentrated in China and the demand for rare earth metals such as neodymium and dysprosium, used as raw materials in permanent magnets (neodymium magnet), is expected to increase rapidly in the near future. It is also important to establish a recycling-based society from the perspective of the conservation of finite and valuable mineral resources and the reduction of the environmental load associated with mining and smelting. In this article, the current status of rare earth resource as well as that of recycling technology for the magnets is reviewed. The importance of establishing an efficient recycling process for rare earths is discussed from the characteristics of supply chain of rare earths, and the technological bases of the recycling processes for the magnet are introduced. Further, some fundamental researches on the development of new recycling processes based on pyrometallurgical process are introduced, and the features of the recycling processes are evaluated.

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Section: Basic Research On Pyrometallur-gical Recycling Technologmentioning

confidence: 99%

Current Status on Resource and Recycling Technology for Rare Earths

Takeda

Okabe

2014

Metallurgical and Materials Transactions E

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“…The reflectivity R of the samples can be calculated from Eq. (3) when given the thickness and frequency (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), as shows on the absorbing curve Fig. 5.…”

Section: The Electromagnetic Parameters and Microwavementioning

confidence: 90%

“…Researchers have made efforts on material types, absorption mechanical strength and structure design to improve the absorptive capacity. But it is difficult to produce microwave materials that use in frequency of 2-4 GHz [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Structure and microwave absorption properties of Nd–Co–Ni alloys

Qiao

Pan

Xiong

et al. 2016

J Mater Sci: Mater Electron

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To study the effect of Ni content on microwave absorption of Nd 2 Co 17 alloy. The Nd 2 Co 17-x Ni x (X = 0.0, 0.2, 0.6, 1.0, 1.4) powders were prepared by arc smelting and high energy ball milling method. The structure and morphology of the powder were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electromagnetic parameters of the powder were measured by vector network analyzer (VNA) at room temperature. The XRD results indicate that the prepared powder maintain the Nd 2 Co 17 phase. The minimum reflectivity value frequency shifts towards the lower frequency with the increase of Ni content. The minimum reflectivity value of Nd 2 Co 15.6 Ni 1.4 alloy reaches about -26.6 dB at 2.9 GHz with the matching thickness of 2.2 mm. And the milled powder was tempered ranging of 50-200°C for 1 h. The minimum reflectivity frequency shifts to higher frequency region compared to the powder without heat treatment. The absorbing frequency bandwidth increases with the tempering treatment increase.

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“…Regarding the former, the possibility in obtaining electromagnetic radiation absorbers, magnets or nanoparticles to be used for magnetic hyperthermia has been shown [4][5][6][7][8]. Concerning the elements' recovery, the extraction of Nd from NdFeB magnets can be performed mainly based on acid or basic solutions (consuming large quantities of no environmentally friendly materials), or molten elements, as detailed elsewhere [9,10].…”

Section: Introductionmentioning

confidence: 99%