Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Access Right: Closed AccessAuthor: search.filters.author.Habibzadeh, Alireza

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  • Article
    A Critical Analysis of Pulverization Mechanism During Hydrogen Decrepitation of End-Of Ndfeb Magnets
    (Elsevier Science Sa, 2025) Habibzadeh, Alireza; Gokelma, Mertol
    Given the increasing demand and limited availability of rare earth elements (REEs), innovative solutions are critical to managing supply risks. Recycling is a key strategy in mitigating these risks, particularly for NdFeB magnets, which consume a large portion of REEs. Among the various recycling processes, hydrogen decrepitation (HD) has gained popularity due to its efficiency in producing fine powders for magnet-to-magnet recycling. While the HD mechanism is commonly attributed to hydride formation in the Nd-rich grain boundary phase, this study presents new findings that challenge this assumption. Through the hydrogenation of End-of-Life (EoL) NdFeB magnets at temperatures ranging from 25 to 400 & ring;C, the results indicate that the primary mechanism of pulverization arises from hydride formation in the Nd2Fe14B matrix rather than in the Nd-rich phase, especially at low temperatures where NdH2 formation is kinetically unfavorable. This revised mechanism was supported by evidence from X-ray diffraction, BSE and SE-SEM imaging, particle size analysis, diffusion modeling, and stress analysis.
  • Article
    Citation - WoS: 1
    Effect of Mechanical Pre-Treatment on the Recovery Potential of Rare-Earth Elements and Gold From Discarded Hard Disc Drives
    (Springer, 2024) Habibzadeh, Alireza; Kucuker, Mehmet Ali; Gokelma, Mertol
    The growing demand for rare-earth elements (REEs) and their limited availability have made REEs critical with high supply risk. E-waste, particularly waste electrical and electronic equipment (WEEE), offers a valuable secondary source. This study assesses the impact of mechanical pre-treatment on the recovery of REEs and gold from discarded hard disk drives (HDDs). We compared recovery efficiencies of REEs and Au using separation techniques, particle sizing, and chemical analyses between two pre-treatment methods: shredding and manual disassembly. Shredding, common in electronic waste processing, leads to oxidation and significant loss of critical raw materials (CRMs), while manual disassembly preserves clean, and non-oxidized NdFeB magnets for magnet-to-magnet recycling. Manually disassembled HDDs were directly analyzed to determine recyclable quantities of REEs and gold. Shredded HDDs underwent sieving, density, and magnetic separation, followed by demagnetization and chemical analysis. Results indicate shredding causes a 73.9% loss of REEs and a 43.8% loss of Au compared to manual disassembly, with increased oxidation due to finer particles. These findings suggest that while shredding is adequate for recovering ferrous and aluminum fractions, manual disassembly is essential for maximizing REE recovery.