Hydrometallurgical Process for Selective Extraction of Nd and Rare-Earth Metals from End-of-Life Hard Disk Drives NdFeB Magnet Scrap

Abstract:

This paper proposed a recycling process for neodymium-iron-boron (NdFeB) magnet scrap from the end-of-life (EOL) of hard disk drives by using hydrometallurgical process. Initial chemical composition of NdFeB magnet scrap was consisted of 25.37%Nd, 6.53%Pr, 0.90%Co, 3.63%B and 63.57%Fe. After de-magnetization and crushing into proper size, magnet scraps were directly leached by H₂SO₄ solution. More than 90% dissolved into acid solution with remaining small amount of residuals and Ni-coated metal. Neodymium precipitated from leached solution by pH-control to the optimum condition at pH 0.6 using NaOH solution. Solid Nd-precipitates XRD pattern was observed in form of NaNd (SO₄)₂.(H₂O) and FeSO₄.(H₂O). Elemental analysis of Nd-precipitates by WD-XRF. The precipitates contained 26.50%Nd, 8.46%Pr and 1.19%Fe. In order to elimination of Fe, Nd-precipitates was leached by using H₂SO₄ solution to dissolve FeSO₄.(H₂O) into acid solution to obtain high concentration of Nd and rare-earth metals (REMs) compound. As a result, XRD pattern of Nd-compound after Fe-removal confirmed that the high purity NaNd (SO₄)₂.(H₂O) compound was obtained. The final composition of precipitates analyzed by WD-XRF was 26.36%Nd, 8.13%Pr with Fe as low as 0.14%Fe.

• Periodical: Key Engineering Materials (Volume 845)
• Pages: 81-86
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.845.81
• Online since: May 2020
• Authors: Panya Buahombura*, Anuthai Kareram, Waraporn Piyawit, Sarum Boonmee
• Keywords: Hydrometallurgical Process, NdFeB Magnet, Neodymium, Rare-Earth Metals, Recycling, Selective Extraction

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