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The rare earth elements (REEs) play a vital role in the development of green energy and high-tech industries. In order to meet the fast-growing demand and to ensure sufficient supply of the REEs, it is essential to develop an efficient REE recovery process from post-consumer REE-containing products. In this research effort, we have developed a supported liquid membrane system utilizing polymeric hollow fiber modules to extract REEs from neodymium-based magnets with neutral extractants such as tetraoctyl digylcol amide (TODGA). The effect of process variables such as REE concentration, molar concentration of acid, and membrane area on REE recovery was investigated. We have demonstrated the selective extraction and recovery of REEs such as Nd, Pr, and Dy without co-extraction of non-REEs from permanent NdFeB magnets through the supported liquid membrane system. The extracted REEs were then recovered by precipitation followed by the annealing step to obtain crystalline REE powders in nearly pure form...

The rare earth elements (REEs) such as neodymium, praseodymium, and dysprosium were successfully recovered from commercial NdFeB magnets and industrial scrap magnets via membrane assisted solvent extraction (MSX). A hollow fiber membrane system was evaluated to extract REEs in a single step with the feed and strip solutions circulating continuously through the MSX system. The effects of several experimental variables on REE extraction such as flow rate, concentration of REEs in the feed solution, membrane configuration, and composition of acids were investigated with the MSX system. A multimembrane module configuration with REEs dissolved in aqueous nitric acid solutions showed high selectivity for REE extraction with no coextraction of non-REEs, whereas the use of aqueous hydrochloric acid solution resulted in coextraction of non-REEs due to the formation of chloroanions of non-REEs. The REE oxides were recovered from the strip solution through precipitation, drying, and annealing steps. The resulting REE oxides were characterized with XRD, SEM-EDX, and ICP-OES, demonstrating that the membrane assisted solvent extraction is capable of selectively recovering pure REEs from the industrial scrap magnets.

We present fabrication of a novel (Nd0.7Ce0.3)10.5Fe83.9 B5.6magnetic powder and SU-8, UV patterened micromagnets. The magnetic powder with an averge particle size of 5μm-6μm has been prepared from an alloy ingot of raw materials which are put in a vacuum induction furnace, melt spun to obtain ribbons with nanocrystalline microstructure, further the ribbons are crushed using vibrating ball milling under intert atmosphere to obtain coarse powder (average particle size of 200μm). In order to obtain 5μm fine powder the course powder is jet milled at 6000rpm under inert atmosphere. The fine (Nd0.7Ce0.3)10.5Fe83.9 magnetic powder (refered to as MQFP-15) was ultrasonically uniformy dispersed in SU8 3010 using a horn tip probe operating at a frequency of 24 kHz. Micromagnets (length of 5mm, width 200 μm, height 30μm) are fabricated from the prepared composite via UV lithography and were tested usigng a SQUID magnetometer showed a remanent magnetization (Mr) of 62.80 emu/g and Coercivity (Hc) of 5290 G at 72 weight percentage of magnetic powder in PDMS matrix.

magnetic powder and polydimethysiloxane bonded material that can be micropatterned into micromagnets. The magnetic powder, with an average particle size of 5 m-6 m, has been prepared from an alloy ingot of raw materials which are put in a va cuum induction furnace and melt spun to obtain ribbons with nanocrystalline microstructure. The ribbons are crushed using vibrating ball milling under inert atmosphere to obtain coarse powder (average particle size of 200 m). In order to obtain 5 m fine powder the course powder is jet milled at 6000rpm under inert atmosphere. The fine magnetic powder (referred to as MQFP-15) is ultrasonically uniformly dispersed in a polydimethylsiloxane matrix (PDMS) using a horn tip probe operating at a frequency of 42 kHz. Micromagnets (diameter of 50 m, height 30 m) are fabricated from the prepared composite via soft lithography and are tested using a SQUID magnetometer, showing a remanent magnetization (M

Isotropic Nd–Fe–B nanocrystalline fine powders with particle size in the range of 1–10 μm have been developed using melt spinning and jet milling. The processing steps primarily consist of melt spinning Nd–Fe–B alloy to obtain ribbons with 25–50 μm thickness, crushing the ribbon to obtain coarse powder with average particle size of about 200 μm, and jet milling the coarse powder to obtain fine powder with average particle size of about 5–6 μm. The effects of jet milling conditions on powder particle size, microstructure, and magnetic properties were systematically studied. For a magnet alloy nominally composed of Nd11.9(Fe0.93Co0.07)82.6B5.5, a particulate yield of D10=2 μm, D50=6 μm, and D90=11 μm and magnetic properties of Br=8.82 kG, Hci=9.5 kOe, and (BH)max=15.3 MGOe have been achieved in melt-spun and jet milled fine powders. The combined advantage of small particle size and high magnetic performance will make the Nd–Fe–B fine powder an attractive candidate for applications such as magnetic fluids, i...