Manual Dismantling Research Articles

A Study on Separating Characteristics of Metals towards Remote Recycling

This study focuses on disassembly and separation processes of recycling of used electronic products. In the previous study, the authors have proposed a concept of remote recycling. The concept can replace manual disassembly and reduce the recycling cost, by carrying out the operation from where labor is relatively inexpensive and sufficient. As a typical electronic product, the paper takes mobile phone as an example and evaluates characteristics in separating valuable metals from used products to examine the feasibility of the concept. It is said that most of the valuable metals of the used electronics are contained in Printed Circuit Board (PCB). Experiment results showed that metals such as Fe, Cu, Al, Cr, Ni and Mg were much more concentrated in roughly crushed and visually separated particles than in manually disassembled PCB. Thus, the paper concluded that visual separation of valuable metals is possible, and this result will be a first step towards implementation of remote recycling.

Disassembly system modeling and design with parts selection for cost, recycling and CO2 saving rates using multi criteria optimization

Environmental issues in supply chains have been serious for not only the reduction of CO2 emissions but also for material starvation. End-of-life assembly products at recycling factories should be disassembled environmentally and economically in consideration of not only low carbonization but also of material circulation. Parts with higher recycling and CO2 saving rates should be selected and manually disassembled; however, the manual disassembly brings a higher cost, instead of disposing of the parts. Moreover, this parts selection also affects a disassembly line balancing.This study proposes a simple and practical modeling and design of multi criteria optimization for lower disassembly cost, higher recycling, and CO2 saving rates by an environmental and economic parts selection, and subsequent disassembly line balancing.

Service Outsourcing in Recycling of Used Small Electronics

It is said that PCB (printed circuit board) of used electronics contains considerable amount of critical metals, rare earths, and so on. However, one of the problems in utilizing such used products is that the valuable materials scatter among huge numbers of small-sized electronics. Efficient methods of collection and concentration are necessary. Although manual disassembly and separation of PCB is a good way to enhance the quality of the recycled materials, it causes a large labor cost. As a solution to this problem, this paper focuses on a new concept of recycling process which is to outsource such manual operation to unspecified workers via internet. The concept will be also helpful to reduce environmental impact caused by unnecessary transportation of the used products. This paper has proposed the concept of the outsourcing of recycling operations and discussed the advantages of the concept. And then, it tried to prototype a mechanism to enable the idea. The paper carried out a basic design of screening and sorting mechanisms and made some experiments of operation. The basic results obtained in this paper clarified that the remote recycling concept is feasible and promising.

Occurrence of emerging flame retardants from e-waste recycling activities in the northern part of Vietnam

Abstract This study investigated the contamination status of 21 emerging flame retardants (FRs) in soils (n = 32) and river sediments (n = 8) from an e-waste recycling (EWR) site in the northern part of Vietnam. Among analyzed FRs, higher levels of decabromodiphenyl ethane (DBDPE) (ND–4200 ng/g dw), 1,2-bis-(2,4,6-tribromophenoxy)ethane (BTBPE) (ND–350 ng/g dw) and Dechlorane Plus isomers (DPs) (ND–65 ng/g dw) were found in soils near EWR workshops and open burning places. The highest concentrations of DBDPE (20 ng/g dw), BTBPE (5.7 ng/g dw) and DPs (6.7 ng/g dw) were also detected in sediments collected from the middle of the EWR site. The levels decreased concomitantly with increasing distance from the EWR site. These results indicate that these FRs were released to the surrounding environment from improper recycling activities, such as manual dismantling of devices and open burning of e-wastes. Moreover, the estimated daily intakes of those FRs via soil ingestion were approximately ten times higher for children than adults. To our knowledge, this is a first comprehensive study on characterization of soil and sediment contamination by a series of emerging FRs at an EWR site in Vietnam.

WEEE management in Europe and China – A comparison

Over the last years Europe and China have developed specific regulations to address the challenge of managing Waste Electrical and Electronic Equipment (WEEE). Households in today’s urban China are similarly equipped with electrical and electronic appliances as households in European metropolitan areas, which in turn will lead to similar per capita generation rates in WEEE. While the challenge is a similar one, the systems, technologies and legislation in place in Europe and China are partly different, partly aligned to each other. In Europe WEEE collection is based on existing municipal structures. Additionally, retail and other take-back channels are in place. In China the informal sector dominates WEEE collection, being more competitive and flexible and offering pecuniary reimbursement to consumers.In Europe manual dismantling as a first treatment step has been gradually replaced by mechanical break up of appliances, followed by sorting out of hazardous and valuable components. In the subsequent second treatment level, cathode ray tubes are separated, whereby compound materials like motors and coils are mechanically treated, printed circuit boards go to special smelters, and plastics are separated and partly recycled. In China large formal dismantling capacities have been set up in recent years. There dismantling practices follow similar principles as in European plants; however, further processing is only partly implemented in Chinese recycling facilities. Specifically metallurgical treatment of printed circuit boards is still not existent in China.Companies selling electrical and electronic products within the EU are obliged to organise collection and treatment. This has led to a larger number of producer responsibility organisations. Financed and controlled by producers and importers, these systems aim to fulfil legal requirements at optimised costs subject to compliance with environmental standards and monitoring requirements. The Chinese system is built on a state controlled fund which subsidies formal recyclers. For these recyclers this financial support is essential to compete with informal recyclers, who operate at lower costs and do not necessarily comply with environmental standards.

Recovery of cathode materials and Al from spent lithium-ion batteries by ultrasonic cleaning

Cathode materials are difficult to separate from Al-foil substrates during the recycling of spent lithium-ion batteries (LIBs), because of the strong bonding force present. In this study, ultrasonic cleaning was used to separate and recycle these cathode materials. The mechanism of separation was ascribed to the dissolution of polyvinylidene fluoride (PVDF) and the cavitation caused by ultrasound. Based on this mechanism, the key parameters affecting the peel-off efficiency of cathode materials from Al foil was identified as solvent nature, temperature, ultrasonic power, and ultrasonic time. The peel-off efficiency of cathode materials achieved ∼99% under the optimized conditions of N-methyl-2-pyrrolidone (NMP) cleaning fluid, 70°C process temperature, 240W ultrasonic power, and 90min of ultrasonication. The cathode materials separated from Al foil displayed a low agglomeration degree, which is beneficial to the subsequent leaching process. Finally, a new, environmentally-sound process was proposed to efficiently recycle cathode materials and Al from spent LIBs, consisting of manual dismantling, ultrasonic cleaning, and picking.

Exposure risks of noise and heavy metals in dismantling lines for recovering waste televisions

Quantities of waste televisions have been generated in the world and manual dismantling was chosen to treat waste televisions. Therefore, exposure risks of pollutants in manual dismantling process should be concerned. In this paper, exposure risks of noise and heavy metals in full manual dismantling line and semi-automatic dismantling line for recovering waste televisions were studied. The highest noise levels exposed in full manual dismantling line and semi-automatic dismantling line were 92.3 dB(A) and 87.9 dB(A), which brought harm to workers. The highest concentrations of total suspended particulates, particulate matter 10, and particulate matter 2.5 exposed in the workshop of full manual dismantling line were 2425 μg/m3, 1624 μg/m3, and 1184 μg/m3. The corresponding values in semi-automatic dismantling line were 1221 μg/m3, 851 μg/m3, and 602 μg/m3. These values were ten times higher than the standard values in Ambient Air Quality Standard. The concentrations of lead in the air caused negative effect to workers, even chronic risk. The highest concentrations of zinc and lead exposed in the ground dust of the workshop reached 4868 mg/kg and 5226 mg/kg, almost ten times higher than the allowed concentration limit. Concentrations of zinc and lead exposed in surface soil of flower bed reached 683 mg/kg and 468 mg/kg. The results indicated noise and heavy metals exposures in dismantling process of waste televisions were harmful. However, Semi-automatic dismantling made a certain progress on environmental performance than full manual dismantling for treating waste televisions. Additionally, measures for controlling the exposure risks of noise and heavy metals were proposed for improving semi-automatic dismantling such as the closed and automatic transport system. This paper provided environmental information about the dismantling process for recovering waste televisions. It also supported scientific information for the government to improve the recovery process of waste televisions on cleaner production.

Mechanical pre-treatment of mobile phones and its effect on the Printed Circuit Assemblies (PCAs)

The recycling of Waste Electrical and Electronic Equipment (WEEE) has attracted a notable amount of interest during the last few decades due to the high metal concentrations and substantial increase in the growth rate of WEEE. In addition, higher recovery and recycling rates required by the European Union demand more comprehensive treatment of WEEE. However, complex product design and the presence of harmful substances together with low concentrations of special metals present challenges for processing. This study examines the effect of mechanical treatment of mobile phones on metal concentrations in the printed circuit assembly (PCA) fraction compared to manual dismantling. The designed mechanical treatment process including crushing, sieving, magnetic-, eddy current- and sensor-based separation was able to separate plastics, ferrous metals, PCA and stainless steel for further treatment. The process separated PCA with an efficiency of 85%. However, the quality of the separated PCAs was poor compared with “pure” manually dismantled PCAs. The primary crushing of mobile phones destroys PCAs thus resulting in the loss of especially precious metals used in the connector coatings and in the surface-mounted components. As a result, the theoretical value of the produced PCA fraction is only half compared to using manual dismantling. However, high labour costs in western countries and low capacity may hinder the feasibility of hand dismantling.

A Pilot Assessment of Occupational Health Hazards in the US Electronic Scrap Recycling Industry

The National Institute for Occupational Safety and Health (NIOSH) surveyed a randomly selected sample of electronic scrap (e-scrap) recycling facilities nationwide to characterize work processes, exposures, and controls. Despite multiple attempts to contact 278 facilities, only 47 responded (17% response rate). Surveyed facilities reported recycling a wide variety of electronics. The most common recycling processes were manual dismantling and sorting. Other processes included shredding, crushing, and automated separation. Many facilities reported that they had health and safety programs in place. However, some facilities reported the use of compressed air for cleaning, a practice that can lead to increased employee dust exposures, and some facilities allowed food and drinks in the production areas, a practice that can lead to ingestion of contaminants. Although our results may not be generalizable to all US e-scrap recycling facilities, they are informative regarding health and safety programs in the industry. We concluded that e-scrap recycling has the potential for a wide variety of occupational exposures particularly because of the frequent use of manual processes. On-site evaluations of e-scrap recyclers are needed to determine if reported work processes, practices, and controls are effective and meet current standards and guidelines. Educating the e-scrap recycling industry about health and safety best practices, specifically related to safe handling of metal dust, would help protect employees.

Environmental risk assessment of CRT and PCB workshops in a mobile e-waste recycling plant.

The mobile e-waste recycling equipment was chosen as the object of this study, including manual dismantling, mechanical separation of cathode ray tubes (CRTs), and printed circuit boards (PCBs) in the two independent workshops. To determine the potential environmental contamination, the noise, the heavy metals (Cu, Cd, Pb), and the environmental impacts of the e-waste recycling processes in the two workshops of the mobile plant have been evaluated in this paper. This study determined that when control measures are employed, the noise within the two workshops (<80 dB) will meet the national standards. In the CRT workshop, Pb was the most polluting metal, with 2.3 μg/m(3) and 10.53 mg/g in the air and floor dust, respectively. The result of a health risk assessment shows that noncancerous effects are possible for Pb (hazard index (HI) = 3.54 in the CRT workshop and HI = 1.27 in the PCB workshop). The carcinogenic risks to workers for Cd are relatively light in both the workshops. From the results of life cycle assessment (LCA), it can be seen that there was an environmental benefit from the e-waste recycling process as a whole.

Analysis on Factors Impeding the Disassembly Process with Consideration on Automated Disassembly Planning

Disassembly is one of the most important elements of product recovery operations. Most of the open literatures on the disassembly process were focused mainly on the method, sequencing and planning. The optimum disassembly sequence of a product for industrial recycling and remanufacturing requires the intervention of an expert in the work areas. In addition to these literatures, systematic studies on the disassembly are still needed for better understanding of its elements. Thus, an experimental investigation was conducted to re-evaluate the first existing approach of disassembly process; reverse-assembly method in disassembling table top fan. To measure the performances of the method, experiments are conducted in reverse assemble method in two ways; manual disassembly and semi-automated disassembly. This is due to the fact that this research work is considering on developing an optimum disassembly sequence for automated disassembly process. Factors which affect the performances will be analysed and discussed. This paper is the proceeding research on the previous paper titled “Experimental Design for Reverse Assembly Based Disassembly Process”.

Proposal of a Design Method for Dismantling Products with Split-Lines

An important process for the reuse and recycling of end of life products is their disassembly. In general, manual disassembly is a labor intensive and costly process. Especially, removing fasteners takes time and cost. For solving this problem, this paper proposes a design method for the partial dismantling of products with split-lines, which are added to the products at the design phase and enable to destruct the products along the line in order to extract target components. This method supports a designer in determining the location of split-lines by using the geometric model of the product. A case study shows that the dismantling of a LCD TV with split-lines reduces the number of manual operations needed for extracting target components.

Proposal of a design method for semi-destructive disassembly with split lines

This paper proposes a computer-aided design method for semi-destructive disassembly with split lines. This method aims at extracting reusable, recyclable, or hazardous components more efficiently than manual disassembly with higher quality than shredding. The split line is a shape feature of a product that enables to destruct the product into desired shape, like pull tabs of cans. The proposed method aids a designer in adding proper split lines to extract target components. A case study showed that the semi-destructive disassembly sequence of an air conditioner with the split lines reduces the number of steps needed for extracting a target component.

Economic and Environmental Evaluation of Fasteners for Active Disassembly: A Case Study for Payment Terminals

Prior research has demonstrated that design for disassembly enables higher recovery rates for precious and critical metals, as well as flame retardant plastics from End-of-Life (EoL) electronics. However, small EoL electronic products are nowadays commonly recycled in a size-reduction based treatment or can be directly treated in an integrated Precious Metal (PM) smelter-refinery. In this article, a methodology is described to calculate the Rate of Return (RoR) on investing in fasteners which can be simultaneously released by the application of an external trigger, following the principle of active disassembly. This methodology is used in the presented case study to calculate the ROR of implementing a pressure sensitive snap-fit in an electronic payment terminal which is sold in a product service system business model. In addition, the economic and environmental performances of an active disassembly based EoL treatment is compared with those of a manual disassembly and a size-reduction based treatment, as well as direct treatment in an integrated PM smelter-refinery. Results of the presented case study demonstrate that the ROR on investing in active fasteners for the case study product is 27%.

Social impact assessment of informal recycling of electronic ICT waste in Pakistan using UNEP SETAC guidelines

New and improved Information and Communication Technology (ICT) is being produced every day. With every new product on the market, an older product becomes obsolete. These obsolete products are being added to the world's fastest growing waste stream, ICT electronic waste (e-waste). This is formally recycled in developed countries, stockpiled, landfilled or shipped to developing countries, such as Pakistan, here it is recycled informally through crude processes (e.g. manual dismantling, burning, dumping and dipping in acids to extract gold and other precious metals). This study assessed the social impacts of informal e-waste recycling in Pakistan using data obtained in a detailed on-site inventory of the processes directly involved in informal e-waste recycling. The inventory and assessment were conducted according to United Nations Environmental Programme (UNEP) guidelines on Social Life Cycle Assessment (SLCA). The results presented in this paper fill an important data gap and can be integrated with data on other stages of ICT product lifecycle to produce a full SLCA of such products.

The use of air separation in recycling CRT TV sets

The aim of this paper is to examine the possibility of use of air separation in recycling CRT TV sets and determine the effect of operating variables of separators. Eight CRT TV sets were collected and after manual disassembly, parts of CRT TV sets were sorted into four fractions taking into account their properties. The subject of this research was the fraction consisting of yokes of a cathode tube, cables, connectors and wires. Testing samples were obtained by manual disassembly, shredding and sieving, after which the separation on the model of a cross-flow gravity air separator with horizontal flow was carried out. Four grain sizes, 4/2mm, 2/1mm, 1/0.5mm and −0.5mm, were tested on the separator. Testing was carried out according to the central composite design for three factors: splitter height, air velocity and feed position. The evaluation of results was carried out by the analysis of two parameters: concentrate grade and recovery. The obtained values of the concentrate grade varied from 45.9% for the smallest grain size of −0.5mm to 89.4% for the grain size of 1/0.5mm while recovery was very high, mostly over 99%. The highest increase of metal content in the concentrate of 21.1% was recorded for the smallest grain size of −0.5%. The Analysis of Variance showed that the splitter height and feed position have the strongest effect on the concentrate grade.

Experimental Design for Reverse Assembly Based Disassembly Process

Product disassembly is a vital strategy for industrial recycling and remanufacturing which generates the desired parts and/or subassemblies by means of separation of a product into its elements. In order to increase disassembly capacity while maintaining the parts quality, new standards had to be established. Manual disassembly work perform by human will create inconsistency in the quality, efficiency, as well as time consuming, whereby it is believe that those weaknesses can be overcome by an automated performance. Therefore, this research work will re-evaluate the existing approach of disassembly process; reverse-assembly method in disassemble a mini toy car. The design methodology is conducted to verify the disassembly process performance and identify factors affecting the performance. The disassembly process experiment will be conducted in two ways; manual and semi-automated disassembly. This paper reviews the design process of the proposed experimental methodology. The important components of the experimental methodology are discussed in this paper.

Life Cycle Inventory of the Production of Rare Earths and the Subsequent Production of NdFeB Rare Earth Permanent Magnets

Neodymium is one of the more critical rare earth elements with respect to current availability and is most often used in high performance magnets. In this paper, we compare the virgin production route of these magnets with two hypothetical recycling processes in terms of environmental impact. The first recycling process looks at manual dismantling of computer hard disk drives (HDDs) combined with a novel hydrogen based recycling process. The second process assumes HDDs are shredded. Our life cycle assessment is based both on up to date literature and on our own experimental data. Because the production process of neodymium oxide is generic to all rare earths, we also report the life cycle inventory data for the production of rare earth oxides separately. We conclude that recycling of neodymium, especially via manual dismantling, is preferable to primary production, with some environmental indicators showing an order of magnitude improvement. The choice of recycling technology is also important with respect to resource recovery. While manual disassembly allows in principle for all magnetic material to be recovered, shredding leads to very low recovery rates (<10%).

Composition Determination of Vehicle Dismantling Waste

In recent years, a large number of toxic and hazardous substances were discharged into environment because of the simple landfill and accumulation of vehivle dismantling waste. Therefore, it is very important to develop the recycling technology of vehivle dismantling waste for the harmless, stability, reduction and resource utilization of vehivle dismantling waste. In this paper, the compositions of vehicle dismantling waste from two different dismantling processes were investigated by manual sorting, infrared spectroscopy and X-ray fluorescence spectrometer, experimental results showed that the vehicle waste from manual dismantling contained more polyurethane, foamed plastic and rubber with low value and the size of waste is lager, the vehicle waste from mechanical dismantling contained more metal and brittle polymer and their size was smaller. The concentration of metal in two kinds of wastes are less than 1%, the total concentration of carbon and hydrogen reach about 70%, so vehicle dismantling waste was suital for recovering ernergy, but the pollution of chlrone from polyvinyl chloride need to be prevented.

Synergizing Industrialized and Developing Countries to Improve Resource Recovery for e–waste: Case Study Belgium–Kenya

Due to high labor costs, e-waste recycling companies in industrialized countries increasingly adopt destructive mechanical pre-processing based treatments. These processes perform poorly for precious metals and plastics due to material incompatibility and increased entropy, resulting in low effective recycling efficiencies for these material categories. In developing countries most e-waste treatments consist of manual dismantling, followed by primitive refining techniques, which is not only inefficient, but also poses a serious threat to the environment. This article assesses, from an economic and environmental perspective, a cooperation scenario between Belgium and Kenya in which manual dismantling and state of the art metal refining techniques for recycling computers are combined. Findings show that international cooperation could offer a more sustainable solution, yet measures must be taken to avoid the “cherry picking” of valuable components and environmentally unsound disposal of the remaining parts.