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Hydrometallurgical recovery of germanium from coal gasification fly ash / Fátima Arroyo in Industrial & engineering chemistry research, Vol. 48 N° 7 (Avril 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3573–3579 Titre : Hydrometallurgical recovery of germanium from coal gasification fly ash : pilot plant scale evaluation Type de document : texte imprimé Auteurs : Fátima Arroyo, Auteur ; Constantino Fernández-Pereira, Auteur ; Joaquín Olivares, Auteur Année de publication : 2009 Article en page(s) : pp. 3573–3579 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Germanium  Fly  ash  Hydrometallurgical  method  Solvent  extraction  method Résumé : In this article, a hydrometallurgical method for the selective recovery of germanium from fly ash (FA) has been tested at pilot plant scale. The pilot plant flowsheet comprised a first stage of water leaching of FA, and a subsequent selective recovery of the germanium from the leachate by solvent extraction method. The solvent extraction method was based on Ge complexation with catechol in an aqueous solution followed by the extraction of the Ge−catechol complex (Ge(C6H4O2)32−) with an extracting organic reagent (trioctylamine) diluted in an organic solvent (kerosene), the relevant reaction probably being 2(C8H17)3N(org) + Ge(OH)4o(aq) + 3(C6H6O2)(aq) ↔ ((C8H17)3NH)2Ge(C6H4O2)3(org) + 4H2O(aq) followed by the subsequent stripping of the organic extract. The process has been tested on a FA generated in an integrated gasification with combined cycle (IGCC) process. The paper describes the designed 5 kg/h pilot plant and the tests performed on it. Under the operational conditions tested, approximately 50% of germanium could be recovered from FA after a water extraction at room temperature. Regarding the solvent extraction method, the best operational conditions for obtaining a concentrated germanium-bearing solution practically free of impurities were as follows: extraction time equal to 20 min; aqueous phase/organic phase volumetric ratio equal to 5; stripping with 1 M NaOH, stripping time equal to 30 min, and stripping phase/organic phase volumetric ratio equal to 5. 95% of germanium were recovered from water leachates using those conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800730h [article] Hydrometallurgical recovery of germanium from coal gasification fly ash : pilot plant scale evaluation [texte imprimé] / Fátima Arroyo, Auteur ; Constantino Fernández-Pereira, Auteur ; Joaquín Olivares, Auteur . - 2009 . - pp. 3573–3579. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3573–3579 Mots-clés : Germanium  Fly  ash  Hydrometallurgical  method  Solvent  extraction  method Résumé : In this article, a hydrometallurgical method for the selective recovery of germanium from fly ash (FA) has been tested at pilot plant scale. The pilot plant flowsheet comprised a first stage of water leaching of FA, and a subsequent selective recovery of the germanium from the leachate by solvent extraction method. The solvent extraction method was based on Ge complexation with catechol in an aqueous solution followed by the extraction of the Ge−catechol complex (Ge(C6H4O2)32−) with an extracting organic reagent (trioctylamine) diluted in an organic solvent (kerosene), the relevant reaction probably being 2(C8H17)3N(org) + Ge(OH)4o(aq) + 3(C6H6O2)(aq) ↔ ((C8H17)3NH)2Ge(C6H4O2)3(org) + 4H2O(aq) followed by the subsequent stripping of the organic extract. The process has been tested on a FA generated in an integrated gasification with combined cycle (IGCC) process. The paper describes the designed 5 kg/h pilot plant and the tests performed on it. Under the operational conditions tested, approximately 50% of germanium could be recovered from FA after a water extraction at room temperature. Regarding the solvent extraction method, the best operational conditions for obtaining a concentrated germanium-bearing solution practically free of impurities were as follows: extraction time equal to 20 min; aqueous phase/organic phase volumetric ratio equal to 5; stripping with 1 M NaOH, stripping time equal to 30 min, and stripping phase/organic phase volumetric ratio equal to 5. 95% of germanium were recovered from water leachates using those conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800730h

Recovery of germanium from aqueous solutions by ion - exchange extraction of its catechol complex / Fátima Arroyo Torralvo in Industrial & engineering chemistry research, Vol. 49 N° 10 (Mai 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 10 (Mai 2010) . - pp. 4817–4823 Titre : Recovery of germanium from aqueous solutions by ion - exchange extraction of its catechol complex Type de document : texte imprimé Auteurs : Fátima Arroyo Torralvo, Auteur ; Constantino Fernández-Pereira, Auteur ; Maria C. Campanario, Auteur Année de publication : 2010 Article en page(s) : pp. 4817–4823 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Ion  exchange  Aqueous  solution Résumé : The paper is concerned with the recovery of germanium from dilute aqueous solutions. The method is based on the sorption of the selective complex formed by catechol with germanium onto low-cost anionic resins. Experimental investigations were undertaken using conventional quaternary ammonium macroporous resins: Amberlite IRA-900 and IRA-958. The influence of pH, metal concentration, and amounts of resin and catechol on the sorption capacity were investigated. For a proper set of experiments, a statistical technique such as a response surface methodology (RSM) has been used. For the investigation of the exchange equilibrium, the experimental data were analyzed using the Langmuir, Freundlich and Dubinin−Radushkevich equations, the Freundlich isotherm in general constituting a better fit. The uptake of the germanium complex by the ion-exchange resins was reversed by acid and neutral solutions. The results obtained showed better performance for IRA-900 than IRA-958, measured in terms of global recovery yields (retention and elution). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22797476 [article] Recovery of germanium from aqueous solutions by ion - exchange extraction of its catechol complex [texte imprimé] / Fátima Arroyo Torralvo, Auteur ; Constantino Fernández-Pereira, Auteur ; Maria C. Campanario, Auteur . - 2010 . - pp. 4817–4823. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 10 (Mai 2010) . - pp. 4817–4823 Mots-clés : Ion  exchange  Aqueous  solution Résumé : The paper is concerned with the recovery of germanium from dilute aqueous solutions. The method is based on the sorption of the selective complex formed by catechol with germanium onto low-cost anionic resins. Experimental investigations were undertaken using conventional quaternary ammonium macroporous resins: Amberlite IRA-900 and IRA-958. The influence of pH, metal concentration, and amounts of resin and catechol on the sorption capacity were investigated. For a proper set of experiments, a statistical technique such as a response surface methodology (RSM) has been used. For the investigation of the exchange equilibrium, the experimental data were analyzed using the Langmuir, Freundlich and Dubinin−Radushkevich equations, the Freundlich isotherm in general constituting a better fit. The uptake of the germanium complex by the ion-exchange resins was reversed by acid and neutral solutions. The results obtained showed better performance for IRA-900 than IRA-958, measured in terms of global recovery yields (retention and elution). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22797476