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Preparation of High Purity Neodymium Oxide from Brazilian Monazite by Ion Exchange



Author(s)

Carlos Alberto da Silva Queiroz, José Antonio Seneda and Walter dos Reis Pedreira Filho

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DOI:10.17265/1934-8975/2015.07.003

A simple and economical chemical process for obtaining high purity neodymium oxide is discussed. The raw material in the form of RE (rare earth) carbonates is produced industrially in Brazil from monazite. Using this concentrate as the feed material, ion exchange with a strong cationic resin, commonly used for water treatment, and without the use of retention ions was used for the fractionating of the REE (rare earth elements). The eluent was ammonium salt of EDTA (ethylenediaminetetraacetic acid) at pH 4.0. The complex of EDTA-neodymium was transformed into neodymium oxides via oxalate precipitation. We produced 99.9% pure Nd2O3 in yields greater than or equal to 80%. Molecular absorption spectrophotometry was used to monitor the neodymium content during the process and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the neodymium oxides. The typical neodymium oxides obtained contained the followings contaminants in micrograms per gram: Sc (4.09); Y (0.39); La (0.78); Ce (5.62); Pr (4.56); Sm (11.10); Eu (1.10); Gd (14.30); Tb (29.3); Dy (4.15); Ho (8.39); Er (13.80); Tm (0.23); Yb (2.29); Lu (0.39). High purity neodymium oxides obtained from this procedure replaced the imported product used in research and development work on rare earth at IPEN/CNEN-SP (Instituto de Pesquisas Energéticas e Nucleares/Comissão Nacional de Eneergia Nuclear-São Paulo).

Neodymium oxide, elemental rare earths separation, rare earths