A new environmentally friendly process for the recovery of gold from electronic waste

Barbieri, Luisa; Giovanardi, Roberto; Lancellotti, Isabella; Michelazzi, Marco

doi:10.1007/s10311-009-0205-2

Cited by 44 publications

(23 citation statements)

References 14 publications

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“…The method contains leaching with aqua regia, where Ag is stable, precipitation of Pd and recovery of Au in nanoparticles form using liquid-liquid extraction with toluene. Furthermore, Barbieri et al 2010 have proposed a method for the separation of precious metals which is based on the oxidation of the other metals by a milder etching agent. The aim of this work is to evaluate the possibility of recovering Au with electrodeposition from aqueous solution obtained after leaching of PCBs in the presence of various other metals.…”

Section: Introductionmentioning

confidence: 99%

Gold recovery from waste electrical and electronic equipment by electrodeposition: A feasibility study

et al. 2015

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Due to rapid technological progress, the replacement of electronic equipment is very often necessary, leading to huge amounts that end up as waste. Printed circuit boards (PCBs) constitute a unique section among Waste Electrical and Electronic Equipment (WEEE), due to their content in precious and high commercial value metals. Gold, among them, is usually present in a very low quantity and its recovery requires complex chemical treatments. The aim of this work is to evaluate the feasibility of recovering Au by electrodeposition from aqueous solutions obtained after leaching of PCBs and electrical contacts prior to the recovery of any other metals. Aqua regia was used as a leachant for the powders obtained after mechanical and thermal treatment of PCBs' and contacts' parts. The leaching solutions have been analysed by ICP in order to detect the most important metals for the electrodeposition. A preliminary study using synthetic solutions of the elements which could interfere with the gold deposition was performed, followed by an electrochemical study of leach solution of PCBs and contacts. The deposition potential of gold was determined in each solution and a short potentiostatic deposition was carried out. The obtained deposits have been observed by SEM and analysed by EDXS in order to confirm the deposition and to evaluate the purity of the obtained deposits. Aqua regia was proved to be an efficient leachant for the dissolution of all metals from powders obtained after thermal treatment of PCBs and contacts. Among the metals present in the leach solution only copper can interfere with the deposition of gold as the reduction peaks of the auric chloride complex and the Cu2+ ions are very close. However, the deposition of Au was possible, even with low efficiency. The deposition rate increases by increasing the temperature at 40 degrees C and the stirring of the electrolyte. A compact nanocrystalline deposit of high purity gold has been obtained by electrodeposition at 0.55 V vs. Ag/AgCl/KCl3M from the contacts' leach solution. Therefore, this study demonstrates the feasibility of gold recovery from PCBs' and contacts' leach solutions by electrodeposition, without any further chemical treatmen

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Section: Introductionmentioning

confidence: 99%

Gold recovery from waste electrical and electronic equipment by electrodeposition: A feasibility study

et al. 2015

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“…Recently, palladium has attracted more and more scientific interest due to its various applications in pharmaceutica, chemicals, electronics, jewelries, catalytic converters, etc. [1][2][3][4][5][6]. Especially, Pd(II) has excellent catalytic treatment of contaminants in water [7][8][9], the catalytic use in C-C bond formation [10,11], and the highly ordered pyrolytic graphite synthesis [12].…”

Section: Introductionmentioning

confidence: 99%

Fluorescent silica nanoparticles and glass surfaces for the detection and removal of Pd(II) ions

2016

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Fluorescent chemosensors based on silica nanoparticles and silicate glass slides were well designed and prepared. The as-prepared fluorescent silica particles and glass slides exhibited highly selective sensing and absorbing abilities to Pd 2? ions in aqueous phase. SiO 2 nanoparticles were first synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS), and then -NH 2 groups were introduced to silica by treating with 3-aminopropyltriethoxysilane (APTES). Subsequently, 4-amino-1,8-naphthalic anhydride (ANA) was incorporated with the reaction of -NH 2 groups. Finally, salicylaldehyde (SA) was introduced by the reaction between amino groups in ANA and the -CHO groups in SA. Thus, the fluorescent silica nanoparticles were obtained. This method was expanded to prepare fluorescent silicate glass slides. Upon the addition of Pd 2? ions, the fluorescence quenched immediately. These chemosensors were selectively sensitive to Pd 2? ions as low as 10 lM. The absorption efficiency of fluorescent nanoparticles and glass slides for Pd 2? reached to 38.38 and 27.50 %, respectively. And the chemosensors also could be easily recycled and reused for at least five times. Fluorescent silica nanoparticles with only ANA or SA (not ANA and SA together) also exhibited the sensing ability to Pd 2? ions; however, it showed the shortage of Pd 2? ions selectivity. It suggested that it is necessary to introduce both ANA and SA for the high sensitivity and selectivity to Pd 2? ions.

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“…% (150-200 ppm)의 Au가 함유되어 있다. 이들 Au는 접촉 및 노출부분 그리고 동, 철 및 은 등의 금속 표면에 약 10 µm 두 께로 피복되어 있기 때문에 일반 저항성 금광석 (refractory gold ore)에 비하여 쉽게 용출시킬 수 있 다 (Lin and Huarng, 1994;Barbieri et al, 2010).…”

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The Leaching and Recovery of Au from Scrap of PCBs

You¹,

Park²

2014

Journal of the Korean earth science society

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This study was carried out to find an environmental friendly and effective way to leach Au and Ag from scrap of Printed Circuit Boards (PCBs) using sodium-hypochlorite solution. In an EDS analysis, valuable metals such as Cu, Sn, Sb, Al, Ni, Pb and Au were all found in PCBs. The highest leaching rates obtained were 1% of pulp density with a chlorine:hypochlorite of 2:1 and a concentration of NaCl at 2 M. The highest Au recovery was observed with the addition of sodium metabisulfite to make a 3 M solution. It is confirmed that the leaching agent (chlorine-hypochlorite) could effectively leach Au and Ag from Printed Circuit Boards (scrap parts) and the additive reagent sodium metabisulfite could easily precipitate Au from the chlorine-hypochlorite solution.

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A new environmentally friendly process for the recovery of gold from electronic waste

Cited by 44 publications

References 14 publications

Gold recovery from waste electrical and electronic equipment by electrodeposition: A feasibility study

Gold recovery from waste electrical and electronic equipment by electrodeposition: A feasibility study

Fluorescent silica nanoparticles and glass surfaces for the detection and removal of Pd(II) ions

The Leaching and Recovery of Au from Scrap of PCBs

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