Comparative study of printed circuit board recycling by cracking of internal layers using organic solvents-dimethylformamide and dimethylacetamide

Verma, Himanshu Ranjan; Singh, K. K.; Mankhand, T R

doi:10.1016/j.jclepro.2016.11.118

Cited by 46 publications

(19 citation statements)

References 23 publications

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“…A decrease in the weight of precious metals and minerals, as well as a significant increase in laptop plastics, compared to desktops, can be noticed from the 2016 data. Various kinds of metals, such Al, Cu, and Sn, and the precious metals gold (Au), silver (Ag), platinum (Pt), and palladium (Pd) [33][34][35][36] are used in PCBs for electrical conduction. PCBs have a complex composition consisting of a polymer (epoxy resin or fiberglass-based) component, various metals, and ceramic materials [37].…”

Section: Introductionmentioning

confidence: 99%

Advanced Recovery Techniques for Waste Materials from IT and Telecommunication Equipment Printed Circuit Boards

2019

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Waste from information technology (IT) and telecommunication equipment (WITTE) constitutes a significant fraction of waste from electrical and electronic equipment (WEEE). The presence of rare metals and hazardous materials (e.g., heavy metals or flame retardants) makes the necessary recycling procedures difficult and expensive. Important efforts are being made for Waste Printed Circuit Board (WPCB) recycling because, even if they only amount to 5-10% of the WITTE weight, they constitute up to 80% of the recovered value. This paper summarizes the recycling techniques applicable to WPCBs. In the first part, dismantling and mechanical recycling techniques are presented. Within the frame of electro-mechanical separation technology, the chain process of shredding, washing, and sieving, followed by one or a combination of magnetic, eddy current, corona electrostatic, triboelectrostatic, or gravity separation techniques, is presented. The chemical and electrochemical processes are of utmost importance for the fine separation of metals coming from complex equipment such as WPCBs. Thermal recycling techniques such as pyrolysis and thermal treatment are presented as complementary solutions for achieving both an extra separation stage and thermal energy. As the recycling processes of WPCBs require adequate, efficient, and ecological recycling techniques, the aim of this survey is to identify and highlight the most important ones. Due to the high economic value of the resulting raw materials relative to the WPCBs' weight and composition, their recycling represents both a necessary environmental protection action, as well as an economic opportunity.

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Section: Introductionmentioning

confidence: 99%

Advanced Recovery Techniques for Waste Materials from IT and Telecommunication Equipment Printed Circuit Boards

2019

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“…The present research was focused on copper and fiberglass recovery to achieve the maximum environmental and economic performance. Although some previous studies found that the solvent treatment at a temperature above 80°C is effective for material recovery from WPCBs , the nonmetallic fraction of WPCBs, in particular epoxy resin, contains Bromine (Br), which is classified as a toxic material especially at higher temperatures. Therefore, the separation and purification processes were conducted at low temperature 50°C, which had already been reported to be sufficient for low‐temperature WPCB separation by solvent .…”

Section: Methodsmentioning

confidence: 99%

Separation and purification of metal and fiberglass extracted from waste printed circuit boards using milling and dissolution techniques

Tatariants

Yousef

Денафас

et al. 2018

Env Prog and Sustain Energy

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Pulverization operations are extensively used in the recycling of waste printed circuit boards (WPCBs) for liberation of metal and fiberglass in powder shape. The types of liberated metals can vary greatly, for instance it can be copper, tin, lead, aluminum, nickel, gold, palladium, and so forth. However, the obtained metal and nonmetal particles remain contaminated by hazardous material—Brominated Epoxy Resin (BER) what can result in series of environmental and health issues during the further processing. The developed approach was focused on the extraction of uncontaminated copper and fiberglass (which are considered the basic elements that can make up >50% of total WPCB weight) in the form of micro‐particles. To achieve this goal, WPCB samples were cut from areas with high copper concentration while the other components like solder and through‐hole pads (containing other metals) were avoided. At the next step, high energy ball milling was used to grind WPCBs and obtain BER/metal and BER/fiberglass particles. After that, Dimethylformamide (DMF) and ultrasonication were used for dissolution of BER in the powder at a low temperature 50°C, whereas the total treatment time was 4 h and solid to liquid ratio was 1:6 (w/v). Finally, centrifugation was employed to separate the liquid phase (BER/DMF solution) from solid phase (metal and fiberglass particles). The experiments were conducted on five WPCB samples of the same weight that were cut from the five different WPCB models. After the experiments used DMF was regenerated by a rotary evaporator. Ultraviolet‐Visible Spectroscopy, metallographic microscope, Fourier transform infrared spectroscopy, and SEM‐EDS were used to examine the structure of recovered BER, fiberglass, regenerated DMF, and base metal compositions of each sample. The results showed that the metal composition of samples directly depended on WPCB model types. Also, the treatment significantly improved the purity of the extracted fiberglass, therefore it can be used as a high‐purity micro‐filler material for composite applications; the same purification was observed for recovered copper. © 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901–1907, 2018

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“…Experiments beyond 433 K were not performed because it may attribute to boiling and decomposition of DMA. The PCB:DMA of 3:10 (wt/vol) was kept fixed during all the experiments for maximum dissolution of BER (Verma et al, 2017a(Verma et al, , 2016. The progress of delamination of PCBs pieces was continuously monitored, and the experiments were extended until satisfactory delamination has been achieved.…”

Section: Dissolution Of Resin and Delamination Of Pcbsmentioning

confidence: 99%

“…Among the various solvents, the organic solvent found most pronounced application because of their low cost, easy operation, regeneration and negligible effluent generation. Solvent dimethylsulfoxide (Zhu et al, 2013b), N,N-dimethyl pyrrolidone (Wath et al, 2015), dimethylformamide (Verma et al, 2017a(Verma et al, , 2016 and dimethylacetamide (DMA) (Verma et al, 2017b) have registered successful liberation of metal clad of PCBs. A comparative assessment of reported solvents has been shown in Table 1.…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies reported that under conditions viz. PCB:DMA ratio of 3:10 (wt/vol), temperature 433 K; the DMA result in the most efficient dissolution of the BER of PCBs, relatively (Verma et al, 2017a(Verma et al, , 2017b. Further, it has also been reported that the spent DMA is entirely recyclable without negligible loss in its efficiency and the dissolved solute is the BER that is recovered as residue, later.…”

Section: Introductionmentioning

confidence: 99%

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Delamination mechanism study of large size waste printed circuit boards by using dimethylacetamide

2017

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Comparative study of printed circuit board recycling by cracking of internal layers using organic solvents-dimethylformamide and dimethylacetamide

Cited by 46 publications

References 23 publications

Advanced Recovery Techniques for Waste Materials from IT and Telecommunication Equipment Printed Circuit Boards

Advanced Recovery Techniques for Waste Materials from IT and Telecommunication Equipment Printed Circuit Boards

Separation and purification of metal and fiberglass extracted from waste printed circuit boards using milling and dissolution techniques

Delamination mechanism study of large size waste printed circuit boards by using dimethylacetamide

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