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- MakaleYalnız künye2026Selective extraction of rare earth elements from end-of-life NdFeB magnets via low-temperature NH4Cl-based chlorination roasting and water leaching
Kumas, Cavit; Prasetia, Hendra; Sumardi, Slamet; Astuti, Widi; Mufakhir, Fika Rofiek; Daulay, Amru; Wicaksono, Mahruri Arif
Neodymium-iron-boron (NdFeB) magnets are critical components in the transition to a low-carbon energy economy due to their superior magnetic properties. They have significantly higher rare earth element (REE) content (25-35%) compared to natural resources (0.15-2%), making end-of-life NdFeB magnets a valuable secondary REE source. In this study, the selective recovery of REEs from end-of-life NdFeB magnets was investigated using water leaching following chlorination roasting with NH4Cl. A series of experiments was conducted to evaluate the effect of NH4Cl on the NdFeB magnet ratio, roasting temperatures, and roasting duration. Under optimal conditions (300 degrees C, 3 h, NH4Cl at twice the stoichiometric requirement), the roasted products were subjected to water leaching (500 rpm, 90 degrees C, liquid - solid ratio of 20 mL/g, 1 h). resulting in over 95% REE dissolution. Rare earth oxalates were precipitated from the pregnant leach solution with 90% efficiency using 1.5 times the stoichiometric requirement of oxalic acid. Subsequent calcination at 850 degrees C for 2 h yielded rare earth oxides with 99.8% REE purity. Moreover, the dissolution of iron was effectively suppressed through a simple two-stage Fe(OH)3 precipitation step, providing a more economical and selective recovery route. Les aimants de n & eacute;odyme-fer-bore (NdFeB) sont des composants critiques de la transition vers une & eacute;conomie & eacute;nerg & eacute;tique & agrave; faible carbone gr & acirc;ce & agrave; leurs propri & eacute;t & eacute;s magn & eacute;tiques sup & eacute;rieures. Ils ont une teneur en & eacute;l & eacute;ments de terres rares (ETR) sup & eacute;rieures (25-35%) aux ressources naturelles (0.15-2%), ce qui rend les aimants de NdFeB en fin de vie une source secondaire pr & eacute;cieuse d'ETR. Dans cette & eacute;tude, on a examin & eacute; la r & eacute;cup & eacute;ration s & eacute;lective des ETR des aimants de NdFeB en fin de vie par lixiviation aqueuse apr & egrave;s grillage chlorurant avec du NH4Cl. On a effectu & eacute; une s & eacute;rie d'exp & eacute;riences pour & eacute;valuer l'effet du rapport NH4Cl/aimant de NdFeB, des temp & eacute;ratures et de la dur & eacute;e de grillage. Dans des conditions optimales (300 degrees C, 3 h et une concentration de NH4Cl deux fois sup & eacute;rieure & agrave; la st oe chiom & eacute;trie requise), on a soumis les produits grill & eacute;s & agrave; une lixiviation aqueuse (500 tr/min, 90 degrees C, rapport liquide/solide de 20 mL/g, 1 h) conduisant & agrave; une dissolution de plus de 95% des ETR. On a pr & eacute;cipit & eacute; les oxalates de terres rares & agrave; partir de la solution de lixiviation enrichie avec une efficacit & eacute; de 90% en utilisant 1.5 fois la quantit & eacute; st oe chiom & eacute;trique requise d'acide oxalique. Une calcination ult & eacute;rieure & agrave; 850 degrees C pendant 2 h a produit des oxydes de terres rares d'une puret & eacute; de 99.8%. De plus, la dissolution du fer & eacute;tait efficacement supprim & eacute;e par une simple & eacute;tape de pr & eacute;cipitation de Fe(OH)3 en deux phases, offrant une voie de r & eacute;cup & eacute;ration plus & eacute;conomique et plus s & eacute;lective.
- Derleme MakaleYalnız künye2026Red mud as a source of scandium: A review
Kumaş, Cavit; Prasetia, Hendra; Astuti, Widi; Sumardi, Slamet; Mufakhir, Fika Rofiek; Fasya, Muhammad Rizki Firdaus
The residue produced during the extraction of aluminum from bauxite ore via the Bayer process is known as red mud (RM), with 0.5–2.5 t of RM generated for each ton of alumina produced. Due to its highly alkaline nature (pH = 10.0–12.5), RM poses significant environmental threats and requires large storage areas. To address this environmental concern and develop sustainable way to utilize RM, extensive research has been conducted in fields such as soil remediation, metal recovery, steel production, catalytic reactions, cheap adsorbents for pollutant removal, ceramics, brick production, and pigment and slag additives for paint production. While early studies on metal recovery from RM focused on the recovery of metals such as Fe and Al, recent years have seen an increase in research on Sc recovery from RM, as RM is now recognized as an important source for Sc. This review examines in detail methods such as direct acid leaching, bioleaching, acid baking, and water leaching used for Sc recovery from RM. Additionally, data on the recovery of not only Sc but also other metals from RM are presented.