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Development of a process for the separation of zinc and copper from sulfuric liquor obtained from the leaching of an industrial residue by solvent extraction / Ligiane R. Gouvea in Minerals engineering, Vol. 23 N° 6 (Mai 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 6 (Mai 2010) . - pp. 492–497 Titre : Development of a process for the separation of zinc and copper from sulfuric liquor obtained from the leaching of an industrial residue by solvent extraction Type de document : texte imprimé Auteurs : Ligiane R. Gouvea, Auteur ; Carlos A. Morais, Auteur Année de publication : 2011 Article en page(s) : pp. 492–497 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Solvent  extraction  Extractive  metallurgy  Hydrometallurgy  Environmental Résumé : This paper describes a study of the separation of zinc and copper from the leach liquor generated in the treatment of the zinc residue (29.6 g/L Zn and 37.4 g/L Cu) by liquid–liquid extraction. In it, the influence of the extractant type and concentration, aqueous phase acidity, contact time and stripping agent concentration were investigated. Organophosphorus extractants (D2EHPA, IONQUEST®801 and CYANEX®272) and the chelating extractants (LIX®63, LIX®984N and LIX®612N-LV) were also investigated. The organophosphorus reagents are selective for zinc, while the chelating extractants are selective for copper. In the experiment, D2EHPA was found to be the best extractant. A sulfuric acid solution was used in the stripping study. Five continuous experiments were carried out until an optimal condition for the separation of the metals Zn and Cu was achieved. Experiment 5 was carried out in three extraction steps, three scrubbing stages and five stripping stages. In this experiment, a pregnant strip solution containing 125 g/L Zn and 0.01 g/L Cu was obtained and the concentration of the metals in the raffinate was 28.3 g/L Cu and 0.49 g/L Zn. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000026 [article] Development of a process for the separation of zinc and copper from sulfuric liquor obtained from the leaching of an industrial residue by solvent extraction [texte imprimé] / Ligiane R. Gouvea, Auteur ; Carlos A. Morais, Auteur . - 2011 . - pp. 492–497. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 6 (Mai 2010) . - pp. 492–497 Mots-clés : Solvent  extraction  Extractive  metallurgy  Hydrometallurgy  Environmental Résumé : This paper describes a study of the separation of zinc and copper from the leach liquor generated in the treatment of the zinc residue (29.6 g/L Zn and 37.4 g/L Cu) by liquid–liquid extraction. In it, the influence of the extractant type and concentration, aqueous phase acidity, contact time and stripping agent concentration were investigated. Organophosphorus extractants (D2EHPA, IONQUEST®801 and CYANEX®272) and the chelating extractants (LIX®63, LIX®984N and LIX®612N-LV) were also investigated. The organophosphorus reagents are selective for zinc, while the chelating extractants are selective for copper. In the experiment, D2EHPA was found to be the best extractant. A sulfuric acid solution was used in the stripping study. Five continuous experiments were carried out until an optimal condition for the separation of the metals Zn and Cu was achieved. Experiment 5 was carried out in three extraction steps, three scrubbing stages and five stripping stages. In this experiment, a pregnant strip solution containing 125 g/L Zn and 0.01 g/L Cu was obtained and the concentration of the metals in the raffinate was 28.3 g/L Cu and 0.49 g/L Zn. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000026

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

Study of the recovery of rare earth elements from computer monitor scraps / Luciene V. Resende in Minerals engineering, Vol. 23 N° 3 (Fevrier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 3 (Fevrier 2010) . - pp. 277–280 Titre : Study of the recovery of rare earth elements from computer monitor scraps : Leaching experiments Type de document : texte imprimé Auteurs : Luciene V. Resende, Auteur ; Carlos A. Morais, Auteur Année de publication : 2011 Article en page(s) : pp. 277–280 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Extractive  metallurgy  Hydrometallurgy  Leaching  Environmental Résumé : This paper describes the study of the coating powder leaching from computer monitors scraps with the view to obtain a liquor which can be treated by hydrometallurgical techniques to purify the metals studied. The technological development observed in recent years has stimulated the application of rare earth (RE) elements. TV tubes and computer monitors present as coating a powder containing some rare earth elements, mainly europium and yttrium. The recovery of the RE elements from electronics scraps is extremely important as the economic and environmental issues are concerned. The results of this study indicated the technical viability of the recovery of the metals. After the leaching process optimization, the europium and yttrium recovery was over 97% and a liquor containing 16.5 g/L Y, 0.55 g/L Eu, 59.0 g/L Zn, 0.20 g/L Fe, 131 g/L View the MathML source, 0.20 g/L Ca and 2.50 g/L Al was obtained. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509003215 [article] Study of the recovery of rare earth elements from computer monitor scraps : Leaching experiments [texte imprimé] / Luciene V. Resende, Auteur ; Carlos A. Morais, Auteur . - 2011 . - pp. 277–280. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 3 (Fevrier 2010) . - pp. 277–280 Mots-clés : Extractive  metallurgy  Hydrometallurgy  Leaching  Environmental Résumé : This paper describes the study of the coating powder leaching from computer monitors scraps with the view to obtain a liquor which can be treated by hydrometallurgical techniques to purify the metals studied. The technological development observed in recent years has stimulated the application of rare earth (RE) elements. TV tubes and computer monitors present as coating a powder containing some rare earth elements, mainly europium and yttrium. The recovery of the RE elements from electronics scraps is extremely important as the economic and environmental issues are concerned. The results of this study indicated the technical viability of the recovery of the metals. After the leaching process optimization, the europium and yttrium recovery was over 97% and a liquor containing 16.5 g/L Y, 0.55 g/L Eu, 59.0 g/L Zn, 0.20 g/L Fe, 131 g/L View the MathML source, 0.20 g/L Ca and 2.50 g/L Al was obtained. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509003215

Thorium and uranium extraction from rare earth elements in monazite sulfuric acid liquor through solvent extraction / Janúbia C. B. S. Amaral in Minerals engineering, Vol. 23 N° 6 (Mai 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 6 (Mai 2010) . - pp. 498–503 Titre : Thorium and uranium extraction from rare earth elements in monazite sulfuric acid liquor through solvent extraction Type de document : texte imprimé Auteurs : Janúbia C. B. S. Amaral, Auteur ; Carlos A. Morais, Auteur Année de publication : 2011 Article en page(s) : pp. 498–503 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Hidrometallurgy  Mineral  processing  Process  optimization  Extractive  metallurgy Résumé : This paper describes the process of extraction of thorium and uranium from the sulfuric liquor generated in the chemical monazite treatment through a solvent extraction technique. The influence of the extractant type and concentration, contact time between phases, type and concentration of the stripping solution and aqueous/organic volumetric ratio were investigated. The results indicated the possibility of extracting, simultaneously, thorium and uranium from a solvent containing a mixture of Primene JM-T and Alamine 336. The stripping was carried out with a hydrochloric acid solution. After selecting the best conditions for the process, a continuous experiment was carried out in a mixer-settler circuit using four stages in the extraction step, five stages of stripping and one stage of the solvent regeneration. A loaded stripping solution containing 29.3 g/L of ThO2 and 1.27 g/L of U3O8 was obtained. The metals content in the raffinate was below 0.001 g/L, indicating a thorium extraction of over 99.9% and a uranium extraction of 99.4%. The rare earths content in the raffinate was 38 g/L of RE2O3. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268751000004X [article] Thorium and uranium extraction from rare earth elements in monazite sulfuric acid liquor through solvent extraction [texte imprimé] / Janúbia C. B. S. Amaral, Auteur ; Carlos A. Morais, Auteur . - 2011 . - pp. 498–503. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 6 (Mai 2010) . - pp. 498–503 Mots-clés : Hidrometallurgy  Mineral  processing  Process  optimization  Extractive  metallurgy Résumé : This paper describes the process of extraction of thorium and uranium from the sulfuric liquor generated in the chemical monazite treatment through a solvent extraction technique. The influence of the extractant type and concentration, contact time between phases, type and concentration of the stripping solution and aqueous/organic volumetric ratio were investigated. The results indicated the possibility of extracting, simultaneously, thorium and uranium from a solvent containing a mixture of Primene JM-T and Alamine 336. The stripping was carried out with a hydrochloric acid solution. After selecting the best conditions for the process, a continuous experiment was carried out in a mixer-settler circuit using four stages in the extraction step, five stages of stripping and one stage of the solvent regeneration. A loaded stripping solution containing 29.3 g/L of ThO2 and 1.27 g/L of U3O8 was obtained. The metals content in the raffinate was below 0.001 g/L, indicating a thorium extraction of over 99.9% and a uranium extraction of 99.4%. The rare earths content in the raffinate was 38 g/L of RE2O3. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268751000004X