Study on the influence of various factors in the hydrometallurgical processing of waste printed circuit boards for copper and gold recovery

Birloaga, Ionela; Michelis, Ida De; Ferella, Francesco; Buzatu, Mihai; Vegliò, Francesco

doi:10.1016/j.wasman.2013.01.003

Cited by 276 publications

(141 citation statements)

References 17 publications

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“…In previous studies, different lixiviant systems, including sulfuric acid, hydrochloric acid, nitric acid, iodide, ammonia, cyanide, thiourea, thiosulphate and microbes, were examined (Huang et al, 2014;Li et al, 2012;Oishi et al, 2007;Hu et al, 2006;Yang et al, 2011). In most cases, an oxidant, usually hydrogen peroxide (H 2 O 2 ) and ferric (Fe 3+ ) due to their high reduction potentials of 1.78 V and 0.77 V, was involved given that metals in WPCBs are found in native and/or alloy form (Birloaga et al, 2013). However, there has been no process solely based on hydrometallurgical methods at the industrial scale (Yazici and Deveci, 2013 (Zhu et al, 2012a(Zhu et al, ,b, 2013 (Zeng et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Comparative study on copper leaching from waste printed circuit boards by typical ionic liquid acids

et al. 2015

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a b s t r a c tWaste printed circuit boards (WPCBs) are attracting increasing concerns because the recovery of its content of valuable metallic resources is hampered by the presence of hazardous substances. In this study, we used ionic liquids (IL) The results showed that all six IL acids could successfully leach copper out, with near 100% recovery. WPCB particle size and leaching time had similar influences on copper leaching performance, while IL acid concentration, hydrogen peroxide addition, solid to liquid ratio, temperature, showed different influences. Moreover, IL acid with HSO 4 À was more efficient than IL acid with CF 3 SO 3 À . These six IL acids indicate a similar behavior with common inorganic acids, except temperature since copper leaching rate of some IL acids decreases with its increase. The results of leaching kinetics studies showed that diffusion plays a more important role than surface reaction, whereas copper leaching by inorganic acids is usually controlled by surface reaction. This innovation provides a new option for recovering valuable materials such as copper from WPCBs.

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Section: Introductionmentioning

confidence: 99%

Comparative study on copper leaching from waste printed circuit boards by typical ionic liquid acids

et al. 2015

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“…In acidic solution, thiourea can be transformed into formamidine disulfide in the presence of an oxidizing agent like H 2 O 2 and ferric ion. Since thiourea is unstable in alkaline solution, the leaching experiments with thiourea were performed in the acidic solution [27][28][29] . Fig.…”

Section: Leaching With Thioureamentioning

confidence: 99%

“…This is ascribed to the slower formation kinetics of formanidine disulphide, which will hinder the dissolution of silver and gold, with ferric ions than hydrogen peroxide 2) . Furthermore, some of thiourea can be oxidized by ferric ion to form either ), which passivates the surface of the metals and thus prevents the leaching of gold 29,31) . Therefore, extensive works are needed to correlate the effect of the constituents in this mixture with the leaching behavior of the metallic gold and silver.…”

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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“…The proposed technologies include mainly pyrometallurgy (Cayumil et al, 2014;Flandinet et al, 2012), hydrometallurgy (Fogarasi et al, 2015;Tuncuk et al, 2012;Birloaga et al, 2014), bio-technology (Rodrigues et al, 2015;Pant et al, 2012;Zhu et al, 2011), and mechanical methods (Chao et al, 2011;Duan et al, 2009). Among these technologies, hydrometallurgical processes with relatively low capital costs, no gas/dust formation, operational selectivity and suitability for small scale applications are propitious alternatives for the treatment of waste PCBs (Birloaga et al, 2013;Xiu et al, 2013). However, most of the hydrometallurgical processes mainly focused on the leaching of copper.…”

Section: Introductionmentioning

confidence: 99%

A novel recovery method of copper from waste printed circuit boards by supercritical methanol process: Preparation of ultrafine copper materials

Xiu

Weng

et al. 2017

Waste Management

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a b s t r a c tIn this study, supercritical methanol (SCM) process was successfully used for the preparation of ultrafine copper materials from waste printed circuit boards (PCBs) after nitric acid pretreatment. Waste PCBs were pretreated twice in nitric acid. Sn and Pb were recovered by the first nitric acid pretreatment. The leach liquor with a high concentration of copper ions after the second nitric acid leaching was subjected to SCM process. The mixture of Cu and Cu 2 O with poor uniformity of particle size was formed due to the effect of ferric iron contained in the leach liquor of waste PCBs, while more uniform and spherical Cu particles with high monodispersity and smaller size could be prepared after the removal of Fe. The size of Cu particles increased obviously with the decline of SCM temperature, and particles became highly aggregated when the reaction temperature decreased to 300°C. The size of Cu particles decreased markedly with the decrease of initial concentration of copper ion in the leach liquor of waste PCBs. It is believed that the process developed in this study is simple and practical for the preparation of ultrafine copper materials from waste PCBs with the aim of recycling these waste resources as a high value-added product.

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Study on the influence of various factors in the hydrometallurgical processing of waste printed circuit boards for copper and gold recovery

Cited by 276 publications

References 17 publications

Comparative study on copper leaching from waste printed circuit boards by typical ionic liquid acids

Comparative study on copper leaching from waste printed circuit boards by typical ionic liquid acids

Leaching of the Mixture of Metallic Gold and Silver

A novel recovery method of copper from waste printed circuit boards by supercritical methanol process: Preparation of ultrafine copper materials

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