- Thesis topic: Recovery of Rare Earth Elements (REEs) from Waste Permanent Magnets by Pyro-Hydrometallurgy Process and Supported Liquid Membrane

- Doi: https://doi.org/10.6840/cycu202000865

- Abstract: 

        Permanent magnets (PMs) play a significant role in electrical and electronic products and therefore their demand in countries is constantly increasing. Recycling is the main technology for metal recovery from many sources and is an approach to reduce waste generation and generates revenue to satisfy demands metals, particularly rare earth elements. The hydrometallurgical method is beneficial for waste magnet recycling as they are easy to operate and feasible. Leaching studies by Taguchi method, solvent extraction, and precipitation process is reported in this study. The optimum parameters of leaching treatment was achieved by unmodified WPMs, 5M of HCl, 338 K temperature, 24 hours, 2% S/L ratio, 800 rpm stirring speed, 0.250 mm particle size. The most influential factor is acid type with the percentage of contribution for leaching of rare earth elements 78% (Nd), 83% (Pr), and 76% (Dy). 1M D2EHPA diluted in isopar-L at pH 2 present an optimum parameter for REEs extraction 81.55%, 83.5% and 87.93% of dysprosium, neodymium, and praseodymium, respectively. The optimum extraction percentage achieved at 90 minutes for neodymium, dysprosium, and praseodymium was 58.62%, 98.46, and 85.59%, as well as for the recovery 63.13%, 15.21%, and 56.29%, respectively from WPMs leach liquor by HFSLM method. In addition, HFSLM method was successfully recovered 90.82% of neodymium from neodymium precipitated within 35 minutes. HFSLM system was successfully applied in the lab-scale for recycling of REEs from industrial waste materials. Moreover, REE oxides characterization was investigated in this study.

Keywords: Leaching, neodymium, recovery, solvent extraction, supported liquid membrane.