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Purification of rare earth elements from monazite sulphuric acid leach liquor and the production of high-purity ceric oxide / Renata D. Abreu in Minerals engineering, Vol. 23 N° 6 (Mai 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 6 (Mai 2010) . - pp. 536–540 Titre : Purification of rare earth elements from monazite sulphuric acid leach liquor and the production of high-purity ceric oxide Type de document : texte imprimé Auteurs : Renata D. Abreu, Auteur ; Carlos A. Morais, Auteur Année de publication : 2011 Article en page(s) : pp. 536–540 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Cerium  Rare  earth  metals  Cerium  oxidation  Process  optimization Résumé : The present work describes the development of an efficient and relatively simple process to obtain high grade CeO2 from sulphuric acid leach liquor. The liquor was obtained through acid digestion of monazite. The steps investigated in the process for obtaining ceric oxide were: (i) purification of the RE elements through their precipitation as rare earth and sodium double sulphate (NaRE(SO4)2·xH2O), (ii) NaRE(SO4)2·xH2O conversion into RE-hydroxide (RE(OH)3) through metathetic reaction and (iii) recovery of cerium and (iv) purification of cerium from the mixture of ceric hydroxide and manganese dioxide precipitate through dissolution of the solid with HCl and precipitation of the cerium through the addition of oxalic acid (H2C2O4) or ammonium hydroxide (NH4OH) solution. The X-ray diffraction spectra of the double sulphate obtained indicated the presence of monohydrated double sulphate. X-ray diffraction and chemical analysis indicated that the precipitation should be carried out at 70 °C and at 1.1 times the stoichiometric ratio of NaOH. An excess of 30% of KMnO4 was necessary to separate cerium from the other RE elements. Both oxalic acid and ammonium hydroxide proved efficient in the precipitation of cerium from the mixture of Ce/Mn obtained in the cerium separation. Following purification, calcinated products were obtained, assaying between 99% and 99.5% CeO2. The cerium recovery yield was greater than 98%. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268751000066X [article] Purification of rare earth elements from monazite sulphuric acid leach liquor and the production of high-purity ceric oxide [texte imprimé] / Renata D. Abreu, Auteur ; Carlos A. Morais, Auteur . - 2011 . - pp. 536–540. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 6 (Mai 2010) . - pp. 536–540 Mots-clés : Cerium  Rare  earth  metals  Cerium  oxidation  Process  optimization Résumé : The present work describes the development of an efficient and relatively simple process to obtain high grade CeO2 from sulphuric acid leach liquor. The liquor was obtained through acid digestion of monazite. The steps investigated in the process for obtaining ceric oxide were: (i) purification of the RE elements through their precipitation as rare earth and sodium double sulphate (NaRE(SO4)2·xH2O), (ii) NaRE(SO4)2·xH2O conversion into RE-hydroxide (RE(OH)3) through metathetic reaction and (iii) recovery of cerium and (iv) purification of cerium from the mixture of ceric hydroxide and manganese dioxide precipitate through dissolution of the solid with HCl and precipitation of the cerium through the addition of oxalic acid (H2C2O4) or ammonium hydroxide (NH4OH) solution. The X-ray diffraction spectra of the double sulphate obtained indicated the presence of monohydrated double sulphate. X-ray diffraction and chemical analysis indicated that the precipitation should be carried out at 70 °C and at 1.1 times the stoichiometric ratio of NaOH. An excess of 30% of KMnO4 was necessary to separate cerium from the other RE elements. Both oxalic acid and ammonium hydroxide proved efficient in the precipitation of cerium from the mixture of Ce/Mn obtained in the cerium separation. Following purification, calcinated products were obtained, assaying between 99% and 99.5% CeO2. The cerium recovery yield was greater than 98%. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268751000066X