Recovery of gold and silver from spent mobile phones by means of acidothiourea leaching followed by adsorption using biosorbent prepared from persimmon tannin

Gurung, Manju; Adhikari, Birendra Babu; Kawakita, Hidetaka; Ohto, Keisuke; Inoue, Katsutoshi; Alam, Shafiq

doi:10.1016/j.hydromet.2012.12.003

Cited by 205 publications

(108 citation statements)

References 42 publications

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“…In addition, recovery of Ag by using the present proceeding avoids using toxic chemicals and restricted disposal problems compared with that from cyanide medium. 6,9,31) Thus, the present studied proceeding is more environmental friendly and has potential to be applied in practice.…”

Section: Proposal Of the Recovery Proceedingmentioning

confidence: 90%

“…Recovery of silver from these leaching solutions was investigated by both solvent extraction [3][4][5][6] and ion exchange methods. [7][8][9] The solvent extraction process offers signi cant advantages as a potential technique for recovering metal ions from solutions. 10,11) Solvent extraction is considered a better technique than ion exchange in terms of process ef ciency, 12) particularly when the concentration of the metal ion to be separated is higher than 1 g/dm 3 .…”

Section: Introductionmentioning

confidence: 99%

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Recovery of Silver from the Nitrate Leaching Solution of a Spent Ag/α-Al2O3 Catalyst by Solvent Extraction and Reduction

2017

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Nitric acid was employed to strip silver from loaded 5,8-diethyl-7-hydroxy-dodecan-6-oxime (LIX63) in the recovery of silver from a leaching solution of a spent Ag/α-Al 2 O 3 catalyst. The loaded LIX63 was obtained by contacting the real leaching solution with 0.5 mol/dm 3 LIX63 diluted in kerosene. In order to produce silver powder by reduction, the HNO 3 in the stripping solution was recovered by extraction with tri 2-ethylhexyl amine (TEHA) followed by stripping with distilled water. Silver powder was obtained by reduction with 0.1 mol/dm 3 L-ascorbic acid. A owsheet was proposed to recover Ag from the leaching solution of the spent Ag/α-Al 2 O 3 catalyst by solvent extraction and reduction with minimum waste emissions.

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Section: Proposal Of the Recovery Proceedingmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Recovery of Silver from the Nitrate Leaching Solution of a Spent Ag/α-Al2O3 Catalyst by Solvent Extraction and Reduction

2017

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“…5 shows the effect of sulfuric acid concentration in 40 g/L thiourea solution on the leaching of metals at the reaction temperature of 90 o C. No gold was dissolved at all and the leaching percentage of silver decreased rapidly from 11.4 to 0.4% as the concentration of H 2 SO 4 increased from zero to 4 M. Sulfuric acid has a strong tendency to protonate thiourea and thus the effective concentration of thiourea would be decreased as sulfuric acid concentration increases. Therefore, the rapid decrease in the leaching percentage of silver might be related to the protonation of thiourea by sulfuric acid 30) . In the mixture of 40 g/L thiourea and 4 M sulfuric acid solution, the effect of adding ferric ion on the leaching of metallic Au and Ag was represented in Table 2 at the reaction temperature of 25 o C. Table 2 shows that addition of ferric ion had favorable effect on the dissolution of silver but the leaching of gold was not affected.…”

Section: Leaching With Thioureamentioning

confidence: 99%

Leaching of the Mixture of Metallic Gold and Silver

Xing¹,

Lee²

2017

Journal of the Korean Institute of Resources Recycling

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주제어 : 금, 은, 염산, thiosulfate, thiourea, AbstractIn order to exclude the effect of uneven distribution of gold in anode slime, the dissolution of gold and silver from the metal mixture was investigated in different systems, such as the mixture of hydrochloric acid and oxidizing reagents (H , Au was completely dissolved but the leaching percentage of Ag was around 1%. In both thiosulfate and thiourea solution, gold was not dissolved at all. The presence of ferric ion in acidic thiourea solution showed a favorable effect on the leaching of silver but further study is necessary to elucidate the combined effect of ferric ion and sulfuric acid.

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“…A exposição do resíduo metálico no meio ambiente pode sofrer alterações tais como: densidade, toxidade, dentre outras propriedades físico-químicas, proporcionando o desequilíbrio ecológico [8]. Para evitar a contaminação de áreas e recursos naturais provocadas pela disposição desses resíduos, diversas alternativas vem sendo aplicadas, umas delas é a minimização dos impactos ambientais através da reciclagem e recuperação dos metais preciosos presentes nas sucatas tecnológicas [9,10]. Recuperar metais preciosos a partir de resíduos de placas de circuito impresso (PCI) tornou-se algo de interesse das empresas, já que os metais preciosos e o cobre representam mais de 95% do valor total intrínseco da placa, além de sua concentração no resíduo ser de até 10 vezes maior que nos minérios [11][12][13].…”

Section: Introductionunclassified

Caracterização De Placas De Circuito Impresso Por Microscopia Eletrônica De Varredura Visando Recuperação De Metais

Caldas¹,

Moraes²,

Tenório³

et al. 2017

Anais Do Congresso Anual Da ABM

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ResumoA recuperação de metais presentes em equipamentos eletroeletrônicos tem atraído interesse em virtude de novas e diferentes tecnologias que visam a reutilização desses elementos químicos em novos processos produtivos. A recuperação de metais das placas de circuito impresso tem atraído o interesse das empresas, pois, ao mesmo tempo que produz bons resultados do ponto de vista econômico, também se pratica o desenvolvimento sustentável, reduzindo a extração de metais da natureza. Este trabalho tem como objetivo caracterizar as placas de circuito impressos (PCI's) de memória de computadores, através de imagens de microscopia eletrônica de varredura com espectroscopia por dispersão de energia (MEV/EDS), a fim de verificar a presença de metais, visando a sua recuperação. Palavras-chave: Reciclagem; Recuperação de metais; Caracterização. CIRCUIT BOARDS PRINTED CHARACTERIZATION BY SCANNING ELECTRON MICROSCOPY AIMING RECOVERY OF METALS AbstractThe recovery of metals from electronic equipment has attracted interest because of new and different technologies that aim to reuse these chemicals elements in production processes. The recovery of metals from printed circuit boards is interesting to the companies because at the same time produces good results from the economic point of view, and promotes a sustainable development through the reduction extraction of nature metal. This work aims to characterize the printed circuit boards (PCI's) from computer memory through scanning electron microscopy and spectroscopic energy dispersive images (SEM / EDS) in order to verify the presence of metals, aiming the recovery of metals.

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Recovery of gold and silver from spent mobile phones by means of acidothiourea leaching followed by adsorption using biosorbent prepared from persimmon tannin

Cited by 205 publications

References 42 publications

Recovery of Silver from the Nitrate Leaching Solution of a Spent Ag/α-Al<sub>2</sub>O<sub>3</sub> Catalyst by Solvent Extraction and Reduction

Recovery of Silver from the Nitrate Leaching Solution of a Spent Ag/α-Al<sub>2</sub>O<sub>3</sub> Catalyst by Solvent Extraction and Reduction

Leaching of the Mixture of Metallic Gold and Silver

Caracterização De Placas De Circuito Impresso Por Microscopia Eletrônica De Varredura Visando Recuperação De Metais

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