Disassembly and physical separation of electric/electronic components layered in printed circuit boards (PCB)

Lee, Jaeryeong; Kim, Young‐Jin; Lee, Jae-chun

doi:10.1016/j.jhazmat.2012.09.053

Cited by 74 publications

(49 citation statements)

References 19 publications

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“…Recovery, dismantling, and recycling are considered among the most effective approaches to waste printed circuit boards (WPCBs) management, but large-scale implementation has been challenging because of projected low cost-to-benefit ratio of processing mixed e-waste components (Chen et al, 2013). Improved understanding of the chemical compositions of WPCBs has aided recyclers (Dervišević et al, 2013;Lee et al, 2012;Richter et al, 1997;Yin et al, 2011). For example, Yamane et al (Luciana Harue et al, 2011) found that WPCBs from mobile phones (MPs) are composed of 63 wt.% metals; 24 wt.% ceramics and 13 wt.% polymers, while WPCBs from personal computers (PCs) are composed of 45 wt.% metals; 27 wt.% polymers and 28 wt.% ceramics.…”

Section: Introductionmentioning

confidence: 99%

Evolution of electronic waste toxicity: Trends in innovation and regulation

Chen

Ogunseitan

Wang

et al. 2016

Environment International

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Rapid innovation in printed circuit board, and the uncertainties surrounding quantification of the human and environmental health impacts of e-waste disposal have made it difficult to confirm the influence of evolving ewaste management strategies and regulatory policies on materials. To assess these influences, we analyzed hazardous chemicals in a market-representative set of Waste printed circuit boards (WPCBs, 1996(WPCBs, -2010. We used standard leaching tests to characterize hazard potential and USEtox ® to project impacts on human health and ecosystem. The results demonstrate that command-and-control regulations have had minimal impacts on WPCBs composition and toxicity risks; whereas technological innovation may have been influenced more by resource conservation, including a declining trend in the use of precious metals such as gold. WPCBs remain classified as hazardous under U.S. and California laws because of excessive toxic metals. Lead poses the most significant risk for cancers; zinc for non-cancer diseases; copper had the largest potential impact on ecosystem quality. Among organics, acenaphthylene, the largest risk for cancers; naphthalene for non-cancer diseases; pyrene has the highest potential for ecotoxicological impacts. These findings support the need for stronger enforcement of international policies and technology innovation to implement the strategy of design-for-theenvironment and to encourage recovery, recycling, and reuse of WPCBs.

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Section: Introductionmentioning

confidence: 99%

Evolution of electronic waste toxicity: Trends in innovation and regulation

Chen

Ogunseitan

Wang

et al. 2016

Environment International

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“…Therefore, the EEC containing precious metals could be selectively treated by suitable hydrometallurgical methods; and therefore, it is expected to make the recycling processes more ef cient and simpler 12) . Studies on the dismantling have attempted to remove the solder, which joins EECs on bare board, by thermal [18][19][20] or mechanical processes 21) . Various heating sources have been employed to melt the solder components such as industrial waste heat 18) and infrared heating 19,20) .…”

Section: Introductionmentioning

confidence: 99%

“…Lee at al. 21) have shown PCB dismantling with automatic mechanical dismantling apparatus by employing diamond grinders. Because these thermal and mechanical separation processes have disadvantages such as consumption of high energy and loss of solder components, respectively, chemical dissolution processes have been investigated as an alternative method using a water-soluble ionic liquid 22) , methanesulfonic acid with hydrogen peroxide 23) , and uorob- oric acid with hydrogen peroxide 24) .…”

Section: Introductionmentioning

confidence: 99%

Dismantling of Electric and Electronic Components from Waste Printed Circuit Boards by Hydrochloric Acid Leaching with Stannic Ions

2017

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A dismantling process for separating electric and electronic components (EECs) from printed circuit board (PCB) was developed by using hydrochloric acid (HCl) leaching with stannic ions (Sn 4+ ). The use of HCl solution with Sn 4+ ions dissolves tin (Sn)-alloy solder that holds EECs on bare board, which allows the EECs to be detached from PCB. The feasibility of the new dismantling process was investigated by examining the effects of temperature, initial Sn 4+ concentration and agitation speed on the dismantling of PCB. The effect of agitation speed was negligible and the dismantling-completion time was reduced rapidly with increasing temperature and initial Sn 4+ concentration. The dismantling of PCB was completed within 30 min under the leaching conditions; HCl concentration, 1 mol/L; initial Sn 4+ concentration, 13,000 mg/L; temperature, 90 C; and agitation speed, 300 rpm. Each metal was enriched after dismantling process; e.g. the content of Ag increased from 0.016% in PCB to 3.118% in registor. It was expected that ef cient PCB recycling process could be designed to recover metals from EECs with higher concentrated metals.

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“…There are many papers reporting on the recovery of high content metals (Cu, Al, Sn) or precious metals (Au, Ag) from WPCBs using physical, chemical, or biological methods, or a combination of these approaches [1][2][3][4][5][6][7][8][9][10][11][12]. However, these processes are very difficult to perform and are expensive not only for the concentration of minor metals but also for their individual recovery.…”

Section: Introductionmentioning

confidence: 99%

“…For these reasons, few studies have focused on the recovery of metals that have low concentrations of electric/electronic components (EECs) due to the diversity of mounted EECs in WPCBs, such as in varistors, condensers, inductors, resistors, diodes, and so on. These EECs consist of various metals, such as zinc, copper, cobalt, and nickel, as well as toxic substances [12]. Among these EECs, metal oxide varistors (MOVs) are widely used in electronic devices.…”

Section: Introductionmentioning

confidence: 99%

Leaching Kinetics of Zinc from Metal Oxide Varistors (MOVs) with Sulfuric Acid

Kim

Lee

2016

Metals

Self Cite

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Abstract:The leaching kinetics of zinc from zinc oxide-based metal oxide varistors (MOVs) was investigated in H 2 SO 4 at atmospheric pressure. Kinetics experiments were carried out at various agitation speeds, particle sizes, initial H 2 SO 4 concentrations, and reaction temperatures. It was determined that the leaching rate of zinc was independent of agitation speed above 300 rpm and also independent of particle size below 105 µm, whereas it dramatically increased with an increasing H 2 SO 4 concentration. Except for when the H 2 SO 4 concentration was varied, the m-values were almost constant at varying agitation speeds (m-values: 0.554-0.579), particle sizes (m-values: 0.507-0.560) and reaction temperature (m-values: 0.530-0.560) conditions. All of the m-values in these experiments were found to be below 0.580. Therefore, it is proposed that the extraction of zinc is a diffusion-controlled reaction. The leaching kinetics followed the D3 kinetic equation with a rate-controlling diffusion step through the ash layers, and the corresponding apparent activation energy was calculated as 20.7 kJ/mol in the temperature range of 313 K to 353 K.

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Disassembly and physical separation of electric/electronic components layered in printed circuit boards (PCB)

Cited by 74 publications

References 19 publications

Evolution of electronic waste toxicity: Trends in innovation and regulation

Evolution of electronic waste toxicity: Trends in innovation and regulation

Dismantling of Electric and Electronic Components from Waste Printed Circuit Boards by Hydrochloric Acid Leaching with Stannic Ions

Leaching Kinetics of Zinc from Metal Oxide Varistors (MOVs) with Sulfuric Acid

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