Recycling of non-metallic fractions from waste printed circuit boards: A review

Guo, Junchao; Guo, Jie; Xu, Zhenming

doi:10.1016/j.jhazmat.2009.02.104

Cited by 346 publications

(174 citation statements)

References 77 publications

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“…The metallic fraction takes up about 30% of the weight content of PCBs and consists of copper, tin, lead, iron, nickel and noble metals (Goosey and Kellner, 2003), whereas the rest is the non-metallic fraction that consists of thermosetting resins, reinforcing materials, brominated flame retardants (BFRs) and other additives (Guo et al, 2009). The recycling rate in Europe barely exceeds 15% (Goosey and Kellner, 2002).…”

Section: Introductionmentioning

confidence: 99%

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

2017

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Degradation of brominated flame retardants present in printed circuit boards (PCBs) was tested using subcritical water in a high pressure reactor. Debromination experiments were carried out in a batch stirred reactor at three different temperatures (225 ºC, 250 ºC and 275 ºC) keeping a solid to liquid (S/L) ratio of PCB:water=1:5 during 180 min. Results indicated that debromination efficiency was increased with temperature (18.5 to 63.6% of bromine present in the original PCB was removed).Thermal decomposition of the debrominated materials was studied and compared with that of the original PCB. Thermogravimetric analyses were performed at three different heating rates (5, 10 and 20 K min -1 ), studying both the pyrolysis (inert atmosphere) and combustion (in air). Pyrolysis runs of the debrominated materials were also performed in a quartz horizontal laboratory furnace at 850 ºC, in order to study the emission of pollutants. More than 99% of the bromine was emitted in the form of HBr and Br 2 . Emissions of polycyclic aromatic hydrocarbons (PAHs) and bromophenols (BrPhs) decreased with the increase in the treatment temperature; naphthalene (10800 -18300 mg kg -1 original sample) and monobrominated phenols (12.8 -16.9 mg kg -1 original sample) were the most abundant compounds.

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Section: Introductionmentioning

confidence: 99%

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

2017

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“…The MF represents around 50% of the weight content of EWs, mainly constituted by Cu 39 (Conesa et al, 2013), and 30% of the weight content of PCBs, consisting of Cu, Sn, Pb, Fe, Ni 40 and noble metals (Goosey and Kellner, 2003). The rest is NMF that is made up of plastic 41 materials, brominated flame retardants (BFRs) and other additives (Guo et al, 2009). 42…”

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confidence: 99%

Pollutant formation in the pyrolysis and combustion of materials combining biomass and e-waste

Soler

Conesa

Íñiguez

et al. 2018

Science of The Total Environment

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Combustion and pyrolysis runs at 850 ºC were carried out in a laboratory scale horizontal 10 reactor with different materials combining biomass and waste electrical and electronic 11 equipment (WEEE). Analyses are presented of the carbon oxides, light hydrocarbons, 12 polycyclic aromatic hydrocarbons (PAHs), polychlorinated benzenes (ClBzs), polychlorinated 13 phenols (ClPhs), polybrominated phenols (BrPhs), polychlorinated dibenzo-p-dioxins and 14 dibenzofurans (PCDD/Fs). Results showed that gas emissions were mainly composed of CO 15 and CO 2 ; the high level of CO found in the pyrolytic runs was easily transformed into CO 2 by 16 reaction with oxygen. The total amount of light hydrocarbons emitted was somewhat higher in 17 the samples containing WEEE, methane being the most abundant light hydrocarbon in all the 18 runs. However, the presence of WEEE reduced the emission of PAHs which clearly decreased 19 with the increase of the oxygen. The total amount of BrPhs increased in the decomposition of 20 the samples containing WEEE, reaching its maximum in pyrolysis runs. Emission of PCDD/Fs 21 was enhanced in pyrolytic conditions and they were easily destroyed in the presence of oxygen. 22 23

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“…Despite the huge efforts to perform this practice in a controlled way, many illegal domestic and backyard recycling is still occurring, generally in overseas countries (Yoshida 2011;Duan et al 2016). This results in a growing uncontrolled trade with WEEE-related polymeric waste streams, aluminium, ferrous and nonferrous metals (Chancerel et al 2009;Guo et al 2009;Dwivedy & Mittal 2010;Kahhat & Williams 2012).…”

Section: Resultsmentioning

confidence: 99%

Towards a generic procedure for the detection of relevant contaminants from waste electric and electronic equipment (WEEE) in plastic food-contact materials: a review and selection of key parameters

Puype

Samsonek

Vilímková

et al. 2017

Food Additives & Contaminants: Part A

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Recently, traces of brominated flame retardants (BFRs) have been detected in black plastic foodcontact materials (FCMs), indicating the presence of recycled plastics, mainly coming from waste electric and electronic equipment (WEEE) as BFRs are one of the main additives in electric applications. In order to evaluate efficiently and preliminary in situ the presence of WEEE in plastic FCMs, a generic procedure for the evaluation of WEEE presence in plastic FCMs by using defined parameters having each an associated importance level has been proposed. This can be achieved by combining parameters like overall bromine (Br) and antimony (Sb) content; additive and reactive BFR, rare earth element (REE) and WEEE-relevant elemental content and additionally polymer purity. In most of the cases, the WEEE contamination could be confirmed by combining X-ray fluorescence (XRF) spectrometry and thermal desorption/pyrolysis gas chromatography-mass spectrometry (GC-MS) at first. The Sb and REE content did not give a full confirmation as to the source of contamination, however for Sb the opposite counts: Sb was joined with elevated Br signals. Therefore, Br at first followed by Sb were used as WEEE precursors as both elements are used as synergetic flame-retardant systems. WEEE-specific REEs could be used for small WEEE (sWEEE) confirmation; however, this parameter should be interpreted with care. The polymer purity by Fourier-transform infrared spectrometer (FTIR) and pyrolysis GC-MS in many cases could not confirm WEEE-specific contamination; however, it can be used for purity measurements and for the suspicion of the usage of recycled fractions (WEEE and non-WEEE) as a third-line confirmation. To the best of our knowledge, the addition of WEEE waste to plastic FCMs is illegal; however, due to lack on screening mechanisms, there is still the breakthrough of such articles onto the market, and, therefore, our generic procedure enables the quick and effective screening of suspicious samples. ARTICLE HISTORY

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Recycling of non-metallic fractions from waste printed circuit boards: A review

Cited by 346 publications

References 77 publications

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

Pollutant formation in the pyrolysis and combustion of materials combining biomass and e-waste

Towards a generic procedure for the detection of relevant contaminants from waste electric and electronic equipment (WEEE) in plastic food-contact materials: a review and selection of key parameters

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