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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Recuperação de metais com alto valor agregado utilizando sistemas aquosos bifásicos / Recovery of high values metals using aqueous two-phases systems

Lemos, Leandro Rodrigues de 05 July 2012 (has links)
Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-03-02T16:20:51Z No. of bitstreams: 1 texto completo.pdf: 1027005 bytes, checksum: a619f4461ffb781e72e23a04a87e5edc (MD5) / Made available in DSpace on 2017-03-02T16:20:51Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1027005 bytes, checksum: a619f4461ffb781e72e23a04a87e5edc (MD5) Previous issue date: 2012-07-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho foram desenvolvidos novos sistemas aquosos bifásicos (SAB), constituídos por polímeros ((poli(óxido de etileno), massa molar 1500 g mol -1 e poli(óxido de propileno), massa molar 400 gmol -1 ) e sais orgânicos (citrato, tartarato, succinato ou acetato) de sódio. Os SAB L64+Na 2 C 4 H 4 O 6 +H 2 O e L64+MgSO 4 +H 2 O foram utilizados para estudar o comportamento de extração de Cu(II) e Zn(II). Os efeitos da concentração do complexante 1-(2-piridilazo)-2-naftol (PAN), pH do meio reacional, natureza do eletrólito formador do sistema e comprimento da linha de amarração (CLA) do SAB, sobre a porcentagem de extração (%E) dos íons metálicos foram investigados. Cu(II) apresentou extração satisfatória (%E = (92,5 ± 1,6) %) em pH = 3,0, enquanto o melhor pH para extração do Zn(II) (%E = 97,8 ± 1,4) %) foi 11. O SAB L64+Na 2 C 4 H 4 O 6 +H 2 O, em pH = 3,0 e proporção PAN/Metal = 3 apresentou a melhor fator de separação (S Cu,Zn = 204) entre os íons estudados. O SAB L35+MgSO 4 +H 2 O foi aplicado para estudar o comportamento de extração de diversos íons metálicos. Em pH = 3,0 e razão PAN/Metal = 3 foram obtido valores de fator de separação entre 10 3 e 10 4 entre o Cu(II) e os concomitantes Al(III), Fe(III), Cd(II), Mn(II), Ni(II), Co(II) ou Zn(II). Este sistema foi aplicado para recuperar cobre de concentrado mineral de cobre, onde o Cu(II) foi extraído para a fase superior (FS) (%E = (90.4 ± 1.1) %), enquanto os outros metais concentraram-se na fase inferior. Os SAB L64+Li 2 SO 4 +H 2 O, L64+Na 3 C 6 H 5 O 7 +H 2 O, L64+(NH 4 ) 3 C 6 H 5 O 7 +H 2 O e PEO1500+ Na 3 C 6 H 5 O 7 +H 2 O foram utilizados para estudar o comportamento de extração de Ag e alguns concomitantes (Cu, Fe e Zn) na presença dos agentes extratores difeniltiocarbazona (Dz) ou tiocianato (SCN - ). O Ag(I) e o Cu(II) foram extraídos preferencialmente para a FS na presença de Dz, enquanto que utilizando SCN - isso ocorre apenas para o Ag(I). O SAB PEO1500+Na 3 C 6 H 5 O 7 +H 2 O em pH = 1,0 e razão SCN - /Ag = 500 apresentou os melhores resultados para separar Ag(I) (%E = (99,9 ± 1,1) %) e os outros íons (Cu(II) (%E = (19,7 ± 0,8) %), Fe(III) (%E = (12,7 ± 0,4) %) ou Zn(II) (%E = (24,8 ± 0,9) %). Este sistema foi aplicado para recuperar prata presente em pilhas botão, ricas em Ag e Zn, obtendo %E = (99,3 ± 2,0) % e %E = (6,09 ± 0,89) % para prata e zinco, respectivamente. / In this work, new aqueous two-phase systems (ATPS) composed by polymer ((poly(ethylene oxide), molecular weight 1500 g mol -1 or poly(propylene oxide), molecular weight 400 g mol -1 ), salt (sodium citrate, sodium tartrate, sodium succinate or sodium acetate) and water were developed. The ATPS L64+Na 2 C 4 H 4 O 6 +H 2 O and L64+MgSO 4 +H 2 O were applied to study the extraction behavior of Cu(II) and Zn(II). The effects of the following parameters on the percentage of extraction (%E) of the metallic ions were evaluated: (i) amount of the extractant 1-(2-pyridylazo)-2-naphthol (PAN); (ii) type of ATPS-forming of electrolyte; (iii) pH; and (iv) tie-line length (TLL). Cu(II) was efficiently extracted at pH = 3.00 (%E = (92.5 ± 1.6) %) and the highest value of %E for Zn(II) was observed at pH = 11.0 (%E = (97.8 ± 1.4) %). A separation factor (S) between Cu(II) and Zn(II) of 204 were obtained using L64+Na 2 C 4 H 4 O 6 +H 2 O system, at pH = 3,00 and molar ratio (PAN/metal) = 3. Moreover, the ATPS L35+MgSO 4 +H 2 O was used to investigate the extraction and separation of Cu(II) from several metallic ions. At pH = 3,0 and molar ratio (PAN/metal) = 3, high values of separation factor were obtained (10 3 to 10 4 ) between Cu(II) and the concomitants Al(III), Fe(III), Cd(II), Mn(II), Ni(II), Co(II) or Zn(II). To evaluate the feasibility of the ATPS for the recovery of copper from real samples, the system was also applied to a leachate of copper concentrate ore and Cu(II) was mostly extracted to top phase (TP) (%E = (90.4 ± 1.1) %), while the others metallic concomitants remained in bottom phase (BP). Finally, the ATPS L64+Li 2 SO 4 +H 2 O, L64+Na 3 C 6 H 5 O 7 +H 2 O, L64+(NH 4 ) 3 C 6 H 5 O 7 +H 2 O and PEO1500+ Na 3 C 6 H 5 O 7 +H 2 O were used to perform extraction studies of Ag and several concomitants (Cu, Fe e Zn) in the presence of the extractants diphenylthiocarbazone (Dz) or potassium thiocyanate (KSCN). With the addition of Dz to the system, Ag(I) and Cu(II) were extracted to TP, while in the presence of KSCN, only Ag concentrated preferentially in polymer-enriched phase. An efficient separation among Ag(I) and the others metallic ions were obtained using PEO1500+Na 3 C 6 H 5 O 7 +H 2 O ATPS, at pH = 1,00 and molar ratio (KSCN/Ag) = 500, conditions in which Ag(I) presented (%E = (99,9 ± 1,1) %) and the %E values for Cu(II), Fe(III) and Zn(II) were (19,7 ± 0,8) %, (12,7 ± 0,4) % and (24,8 ± 0,9) %, respectively. Moreover, the same system was applied to silver extraction from a leachate of button cells, obtaining %E = (99,3 ± 2,0) % and %E = (6.09 ± 0,89) % for silver and zinc, respectively.

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