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The solvent extraction of yttrium and neodymium from copper pregnant leach solutions (PLS) using Primene JM-T, a primary aliphatic amine, has been studied. Effect of contact time, pH, sulfate concentration, and extractant concentration were investigated using synthetic and actual PLS systems. Standard experimental conditions were 5 minute contact time, pH ~2.5, 10% v/v Primene JM-T concentration, and 1:1 O:A phase ratio. Distribution isotherms were constructed for the pure systems and for actual copper leach solutions. Synthetic solutions contained 100 ppm Y and ~75 ppm Nd. Copper PLS contained 2.1 ppm Nd and 14.9 ppm Y. Results showed that complete extraction of both yttrium and neodymium occurred within five minutes and at pH values greater than 1. It was also found that sulfate concentration does not inhibit extraction at any concentration. Additionally, the distribution isotherms created show that extraction for these metals can operationally take place in one stage from both synthetic solutions and copper leach solutions.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

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Orientador: Massao Ionashiro / Co-orientador: Gilbert Bannach / Banca: Adelino Vieira de Godoy Netto / Banca: Ronaldo Spezia Nunes / Banca: Salvador Claro Neto / Banca: Lázaro Moscardini D'Assunção / Resumo: No presente trabalho foram sintetizados em solução aquosa os compostos Ln(L)3nH2O - onde Ln representa os íons lantanídeos trivalentes (La ao Lu, exceto o promécio) e o ítrio(III) e L representa o íon mandelato (C6H5CH(OH)CO2 -)). Os compostos foram sintetizados por lenta adição de quantidades estequiométricas do ligante mandelato de sódio nas respectivas soluções de cloretos ou nitratos de lantanídeos e de ítrio, sob agitação contínua. A formação dos compostos de lantânio ao neodímio foi verificada após a manutenção das soluções em ebulição durante 30 minutos. Após a sua filtração, observou-se grande perda por solubilidade destes compostos durante a lavagem dos seus precipitados, sendo obtidas apenas pequenas quantidades dos mesmos. Devido a isso, foi realizada nova preparação destes compostos por meio da reação dos seus respectivos carbonatos com o ácido mandélico em ligeiro excesso. Já para os compostos de samário ao lutécio e ítrio a precipitação ocorreu de forma instantânea assim que se adicionou o ligante aos cloretos dos respectivos íons metálicos. A caracterização dos compostos no estado sólido foi realizada através da utilização das seguintes técnicas: complexometria; difratometria de raios X pelo método do pó; espectroscopia de reflectância total atenuada na região do infravermelho; termogravimetria e análise térmica diferencial simultâneas (TG-DTA); termogravimetria e termogravimetria derivada (TG/DTG); termogravimetria e calorimetria exploratória diferencial simultâneas acopladas à espectroscopia de absorção na região do infravermelho com transformada de Fourier (TG-DSC/FTIR) e calorimetria exploratória diferencial (DSC). Estas técnicas forneceram informações sobre a estequiometria, a desidratação, os sítios de coordenação, o comportamento térmico, composição e estrutura dos compostos sintetizados. Com os resultados obtidos pelas curvas TG e pela... / Abstract: In the present work, the compounds Ln(L)3nH2O - where Ln represents trivalent lanthanide (La to Lu, except promethium) and yttrium(III) ions and L is mandelate (C6H5CH(OH)CO2 -)) - have been synthesized. The compounds were synthesized by stoichiometric addition of the sodium mandelate ligand to the respective solutions of chloride or nitrate lanthanides and yttrium, slowly with stirring. The formation of the lanthanum to neodymium compounds occurred after maintaining the solutions under ebullition for 30 minutes. After filtration, due to a great loss during the washing of these precipitates, small quantity of these mandelates were obtained. Thus, the same were also prepared by neutralization of the respective lanthanide carbonates with mandelic acid in slight excesso. The characterization of these compounds in solid state was performed using the following techniques: complexometry; X-ray powder diffractometry; infrared spectroscopy; simultaneous thermogravimetry and differential thermal analysis (TG-DTA); thermogravimetry and derivative thermogravimetry (TG/DTG); simultaneous thermogravimetry and differential scanning calorimetry coupled to absorption spectroscopy in the infrared region with Fourier transform (TG-DSC / FTIR) and differential scanning calorimetry (DSC). These techniques provided information about stoichiometry, dehydration, coordination sites, thermal behavior, composition and structure of synthesized compounds. From TG curves and complexometry results, a general formula could be established for these compounds in the solid state. The X-ray powder patterns pointed out that the synthesized compounds have a low crystalline structure and evidence concerning the formation of isomorphous series. The infrared spectroscopy data suggest that the mandelate ion acts as a chelating bidentate ligand towards the metal ions considered in this work, with a prominently ionic character. The TG-DTA and DSC curves provided... / Doutor

Nenhuma / Foi realizado neste trabalho o estudo da recuperação de európio e ítrio de monitores de computadores sucateados por meio de técnicas hidrometalúrgicas. O trabalho foi composto de três etapas: (i) lixiviação ácida do pó de revestimento da tela de monitores CRT; (ii) separação dos elementos de interesse por extração por solventes em escala de bancada testes descontínuos e (iii) otimização da etapa (ii) em escala micro piloto testes contínuos. Na etapa de lixiviação ácida investigou-se a influência do agente lixiviante, da relação ácido/amostra, tempo e temperatura de reação na porcentagem de solubilização de európio e ítrio do resíduo em estudo. Obteve-se um máximo de solubilização destes (98% p/p) com o emprego de H2SO4 na relação ácido/amostra 1250g/kg em temperatura ambiente (25 C), 10% de sólidos e com agitação mecânica por 30 minutos. O licor obtido no processo de lixiviação, contendo 11,9 g/L de ítrio e 0,72 g/L de európio, foi submetido a testes descontínuos de extração por solventes com a finalidade de separação dos dois íons metálicos. Investigou-se o desempenho dos seguintes extratantes orgânicos no rendimento de extração das espécies de interesse: DEHPA, IONQUEST 801, CYANEX 272 e PRIMENE JMT. O DEHPA na concentração de 1,0 mol/L mostrou-se mais eficiente na separação do par Y/Eu, fator de separação igual a 111,4 na relação de fase A/O = 1 e agitação mecânica por 10 minutos. A partir da isoterma de extração e construção do diagrama McCabe-Thiele, observou-se que dois estágios de extração na relação A/O = 1,1 são suficientes para extrair todo o ítrio da fase aquosa para a fase orgânica, enquanto que o európio fica na fase aquosa. Na lavagem do orgânico carregado, uma solução de H2SO4 0,75 mol/L na relação de fase O/A = 5 foi suficiente para retirar todas as espécies coextraídos na etapa de extração. No processo de reextração, obteve-se 67% de reextração de ítrio da fase orgânica para a fase aquosa com o emprego de HCl 5,0 mol/L na relação de fase O/A = 1. A partir da curva de equilíbrio de reextração, determinou-se que são necessários no mínimo 12 estágios de reextração para se reextrair todo o ítrio da fase orgânica. Após definidas as melhores condições de extração, lavagem e reextração na etapa descontínua, realizou-se cinco ensaios contínuos de extração por solventes em escala micro piloto até se atingir a condição ótima de separação dos elementos em estudo. A melhor separação foi alcançada quando o circuito operou com três estágios de extração, sete de lavagem e quinze de reextração. Ao final do processo obteve-se um rafinado com 0,55 g/L de Eu, 16,7 g/L de Zn e concentração de Y menor que 0,001 g/L. No reextrato, a concentração de Y é de 41,4 g/L e 0,06 g/L de Eu, enquanto que a concentração de Zn foi menor que 0,001 g/L. / This work deals with the study of the recovery of europium and yttrium from discarded computer monitors through hydrometallurgical techniques. It comprises three phases: (i) acid leaching of the coating powder of the monitor screens CRT; (ii) separation of the concerning elements through solvent extraction in a laboratory bench scale discontinuous tests, and (iii) optimisation of phase ii in a micro pilot scale continuous tests. In the acid leaching phase, it was investigated the influence of the leaching agents, the relation acid/sample, time and temperature of the reaction in the percentage of solubilisation of europium and yttrium from the studied residue. The maximum solubilisation achieved (98 w/t%) occurred when H2SO4 in an acid/sample relation of 1250g/kg at room temperature (25 C), 10% of solids and mechanical agitation for 30 minutes were used. The liquor obtained in the leaching process, containing 11.9 g/L of yttrium and 0.72 g/L of europium, was submitted to solvent extraction discontinuous experiments aiming at the separation of the two metallic ions. The behaviour of the following organic extractants - DEHPA, IONQUEST 801, CYANEX 272 and PRIMENE JMT was investigated in relation to the performance of the extraction of the concerned species. DEHPA in concentration of 1.0 mol/L showed to be more efficient in the separation of the pair Y/Eu, with a separation factor equal to 111,4 for phase relation A/O =1, under mechanical agitation for 10 minutes. Based on the McCabe-Thiele diagram, it could be observed that two extraction stages in the relation A/O =1.1 were enough to extract all the yttrium in the aqueous phase to the organic phase, whereas the europium remains in the aqueous phase. In the loaded organic scrubbing, a H2SO4 0.75 mol/L solution in the relation phase O/A of 5 proved to be sufficient to remove all the co-extracted species in the extraction phase. In the stripping phase, 67% of the yttrium extraction was obtained from the organic phase to the aqueous phase by employing HCl 5.0 mol/L in the relation phase O/A = 1. From the stripping isotherm, it was determined that at least 12 stages of stripping are necessary in order to extract all the yttrium in the organic phase. After defining the best extraction, scrubbing and stripping conditions in the discontinuous phase, five continuous solvent extraction experiments were carried out in a micro pilot scale, until the optimum condition for separation of the elements under study was achieved. This degree of separation was attained when the circuit operated with three separation stages, seven washing stages and fifteen stripping phases. At the end of the process, a raffinate containing 0,55 g/L of Eu and 16,7 g/L of Zn and a pregnant stripping solution with 41,4 g/L of Y and 0,06 g/L of Eu was achieved.

Orientador: Ana Maria Pires / Banca: Marian Rosaly Davolos / Banca: Maria Aparecida Zaghete Bertochi / Banca: Edenir Rodrigues Pereira Filho / Banca: Diogo Paschoalini Volanti / Resumo: Neste trabalho investigou-se a influência da concentração dos agentes complexantes etilenoglicol (EG) e sorbitol (SB) nas propriedades estruturais e fotoluminescentes do luminóforo Y2O3:Eu3+ (2 mol%) obtido pelo método Pechini modificado. A quimiometria, em especial, planejamento de experimentos (Design of Experiments - DOE), foi aplicada para planejar a proporção dos precursores dos luminóforos. Todos os dados estruturais, morfológicos e espectroscópicos relacionados aos luminóforos preparados pela variação dos parâmetros de síntese foram sistematicamente interpretados pelo uso de ferramentas de quimiometria de forma a gerar uma análise comparativa consistente entre todos os óxidos. Padrões de difração de todas as amostras são característicos da estrutura forma-C de óxido de ítrio, e a equação de Scherrer aplicada aos dados de difração de raios X indicaram que ambos agentes complexantes resultaram em partículas de Y2O3:Eu3+ com tamanho de cristalito similares no intervalo de 19 a 28 nm. Por imagens de microscopia eletrônica de varredura e de transmissão foi possível confirmar que independente do precursor utilizado, são formados aglomerados de partículas esferoidais com diâmetro de 10 a 30 nm no caso de óxidos obtidos via etilenoglicol e diâmetros maiores de 10 a 50 nm para partículas preparadas utilizando sorbitol. Espectros de fotoluminescência de todos os luminóforos exibiram as emissões no vermelho no intervalo de 550-750 nm esperadas atribuídas a todas as transições 4f-... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The investigation of ethylene glycol (EG) and sorbitol (SB) complexing agents concentration on structural and photoluminescence (PL) properties of Y2O3:Eu3+ (2 mol%) oxides obtained by Pechini method is reported. The chemometrics, in special, Design of Experiments (DOE), was applied to plan phosphor precursor's ratio. All structural, morphological and spectroscopic data related to the phosphors produced by synthesis parameters variation were systematically interpreted by using chemometrics tools in order to provide a consistent comparative analysis of all oxides. Diffraction patterns for all samples are characteristic of yttrium oxide C-form structure, and Scherrer's equation applied to X-ray diffraction data indicated that both complex agents yielded Y2O3:Eu3+ particles with similar crystallite size in the range of 19 to 28 nm. By SEM and TEM images it was possible to confirm that particles, independently on the precursor used, form agglomerates of spheroidal particles with a diameter in the range of 10 to 30 nm in the case of the oxides obtained via ethylene glycol and a larger diameter range of 10 to 50 nm for the particles produced by using sorbitol. Photoluminescence data for all phosphors exhibit the expected red emission in the range of 550-750 nm ascribed to all Eu3+ 4f-4f set of transitions. Despite the fact that no detectable difference is observed in the spectra profile indicating that Eu3+ environment should be identical for all samples independent on the agent co... (Complete abstract click electronic access below) / Doutor

Lai, Kwing To = 鐵基超導體的合成與分析 : 氟及釔合摻SmFeAsO / 黎烱韜. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Abstracts in English and Chinese. / Lai, Kwing To = Tie ji chao dao ti de he cheng yu fen xi : fu ji yi he shan SmFeAsO / Li Jiongtao. / Abstract --- p.i / 摘要 --- p.iii / Acknowledgements --- p.v / Table of contents --- p.vii / List of table captions --- p.x / List of figure captions --- p.xi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Superconductivity --- p.1 / Chapter 1.1.1 --- Physical properties --- p.3 / Chapter 1.1.1.1 --- Zero resistance --- p.3 / Chapter 1.1.1.2 --- Meissner effect --- p.4 / Chapter 1.1.1.3 --- Josephson effect --- p.5 / Chapter 1.1.2 --- Type I and II superconductivity --- p.7 / Chapter 1.2 --- Iron-based superconductors --- p.7 / Chapter 1.2.1 --- Classifications and structures --- p.8 / Chapter 1.2.2 --- Physical properties --- p.12 / Chapter 1.2.3 --- Iron-based superconductors versus Cuprate superconductors --- p.13 / Chapter 1.2.4 --- Correlation between high-Tc superconductivity and magnetism --- p.14 / Chapter 1.2.5 --- Quantum phase transition by doping --- p.16 / Chapter 1.2.6 --- Sample preparation of undoped and doped iron-based superconductors --- p.17 / Chapter 1.3 --- Objectives of this research project --- p.18 / References --- p.20 / Chapter Chapter 2 --- Literature Review --- p.22 / Chapter 2.1 --- Theories of superconductivity --- p.22 / Chapter 2.1.1 --- London equation --- p.22 / Chapter 2.1.2 --- Ginzburg-Landau theory --- p.24 / Chapter 2.1.2.1 --- Mean-field theory and Landau theory --- p.24 / Chapter 2.1.2.2 --- Spatial varying order parameter and Gauge symmetry --- p.27 / Chapter 2.1.2.3 --- Applications --- p.31 / Chapter 2.1.3 --- BCS theory --- p.35 / Chapter 2.2 --- Magnetism in condensed matters --- p.39 / Chapter 2.2.1 --- Ferromagnetism and Antiferromagnetism from local moments --- p.40 / Chapter 2.2.1.1 --- Mathematical explanation in the mean-field approach --- p.40 / Chapter 2.2.1.2 --- Exchange interaction --- p.43 / Chapter 2.2.2 --- Antiferromagnetism in magnetic metals: Spin density wave --- p.45 / References --- p.52 / Chapter Chapter 3 --- Methodology and Instrumentation --- p.53 / Chapter 3.1 --- Sample preparation --- p.53 / Chapter 3.2 --- Characterization --- p.55 / Chapter 3.2.1 --- Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDX) --- p.55 / Chapter 3.2.2 --- Transmission electron microscopy (TEM) and Electron diffraction --- p.55 / Chapter 3.2.3 --- X-ray diffraction (XRD) --- p.56 / Chapter 3.2.4 --- X-ray photoelectron spectroscopy (XPS) --- p.57 / Chapter 3.2.5 --- Physical properties measuring system (PPMS) --- p.58 / Chapter 3.2.5.1 --- Transport properties --- p.58 / Chapter 3.2.5.2 --- Magnetic properties --- p.60 / Chapter 3.2.6 --- Raman spectroscopy --- p.62 / Chapter 3.3 --- Precautions --- p.62 / References --- p.63 / Chapter Chapter 4 --- Results --- p.64 / Chapter 4.1 --- Fluorine-doped SmFeAsO --- p.64 / Chapter 4.1.1 --- Morphologies and microstructures --- p.67 / Chapter 4.1.2 --- Phase and composition --- p.69 / Chapter 4.1.3 --- Lattice constants --- p.72 / Chapter 4.1.4 --- Transport properties --- p.73 / Chapter 4.1.5 --- Magnetic properties --- p.74 / Chapter 4.2 --- Fluorine and Yttrium co-doped SmFeAsO --- p.78 / Chapter 4.2.1 --- Morphologies and microstructures --- p.79 / Chapter 4.2.2 --- Phase and composition --- p.82 / Chapter 4.2.3 --- Lattice constants --- p.84 / Chapter 4.2.4 --- Oxidation state --- p.85 / Chapter 4.2.5 --- Transport properties --- p.88 / Chapter 4.2.6 --- Magnetic properties --- p.89 / Chapter 4.3 --- Quality control of the superconducting products --- p.94 / Chapter 4.3.1 --- Intermediate product SmAs --- p.95 / Chapter 4.3.2 --- Intermediate product FeAs --- p.104 / Chapter 4.3.3 --- Effects of annealing temperature --- p.110 / Chapter 4.4 --- Summary --- p.112 / References --- p.112 / Chapter Chapter 5 --- Discussions --- p.113 / Chapter 5.1 --- Effects of F doping --- p.113 / Chapter 5.2 --- Effects of YF doping --- p.115 / Chapter 5.3 --- Improvements in the quality of the superconducting samples --- p.117 / Chapter 5.4 --- Summary --- p.124 / References --- p.125 / Chapter Chapter 6 --- Conclusions and Suggestions for Future work --- p.126 / Chapter 6.1 --- Conclusions --- p.'126 / Chapter 6.2 --- Suggestions for future work --- p.128 / References --- p.130 / Chapter Appendix A --- Sealing samples in small evacuated silica capsules for DTA measurements --- p.131 / Chapter Appendix B --- AC susceptibility measurement --- p.133 / Chapter Appendix C --- Suggested readings for beginners --- p.135 / Bibliography --- p.138

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