Recycling-oriented characterization of small waste electrical and electronic equipment

Current overview and future perspective in fungal biorecovery of metals from secondary sources

Microorganisms are intimately involved in many biogeochemical processes that underpin the transformation of metals and cycling of related substances, such as metalloids and radionuclides. Many processes determine the mobility and bioavailability of metals, thereby influencing their transfer to the environment and living organisms. These processes are closely related to global phenomena such as soil formation and bioweathering. In addition to environmental significance, microbial metal transformations play an essential role in both in situ and ex situ bioremediation processes for solid and liquid wastes. The solubilization of heavy metals from industrial waste and soil is commonly used in bioremediation. Moreover, immobilization processes are applicable to bioremediation of metals and radionuclides from aqueous solutions. This review provides an overview of critical metal extraction and recovery from secondary sources, applied microorganisms and methods, metal-microbe interactions, as well as a detailed description of known metal recovery mechanisms.

Chemical and Microbial Leaching of Valuable Metals from PCBs and Tantalum Capacitors of Spent Mobile Phones

We compared chemical and microbial leaching for multi-metal extraction from printed circuit boards (PCBs) and tantalum capacitor scrap. A mixed consortium of acidophiles and heterotrophic fungal strains were used in the experiments and compared to chemical leaching using specific acids (sulfuric, citric and oxalic acids). Under optimum conditions, 100% extraction efficiency of Cu, and nearly 85% of Zn, Fe, Al and Ni were achieved from PCB and tantalum capacitor scrap samples using sulfuric acid. The mixed consortium of acidophiles successfully mobilized, Ni and Cu (99% and 96%, respectively) while Fe, Zn, Al and Mn reached an extraction yield of 89, 77, 70 and 43%, respectively, from the PCB samples. For the tantalum capacitor samples, acidophiles mobilized 92% Cu, 88% Ni, 78% Fe, 77% Al, 70% Zn and 57% Mn. Metal mobilization from PCBs and tantalum capacitor scrap by A. niger filtrate showed efficient solubilization of Cu, Fe, Al, Mn, Ni, Pb and Zn at an efficiency of 52, 29, 75, 5, 61, 21 and 35% from PCB samples and 61, 25, 69, 23, 68, 15 and 45% from tantalum capacitor samples, respectively. Microbial leaching proved viable as a method to extract base metals but was less specific for tantalum and precious metals in electronic waste. The implications of these results for further processing of waste electronic and electrical equipment (WEEE) are considered in potential hybrid treatment strategies.

Systematic Quantification of Waste Compositions: A Case Study for Waste of Electric and Electronic Equipment Plastics in the European Union

Waste Electric and Electronic Equipment (WEEE) is a prominent and increasing waste stream for which the Commission of the European Union has put in place ambitious recycling targets. However, these targets can only be achieved by ensuring that both industry and governments develop adequate infrastructure and policies for recycling plastics in an economically and technically optimal manner. Unfortunately, a quantitative overview of WEEE plastics covering the composition of waste streams down to the product component level and describing polymer and additive concentrations, is currently lacking. This hinders policymakers and recyclers in making strategic decisions regarding WEEE plastics recycling. Therefore, a novel method is proposed in this paper combining experimental results with findings from prior literature in order to provide sound quantitative insights into the volume and characteristics of the plastics content of WEEE collected in the European Union. The provided overview was obtained through a combination of proprietary experimental data and a statistical data integration method. More specifically, over 3800 samples awere analysed through manual composition analysis, FTIR, and XRF. The obtained results were integrated with data from prior literature through a novel data integration methodology based on linear opinion pools. The obtained results confirm that distinct plastic types can be found in different product categories and that flame retardants are only found in high concentrations in specific waste streams or components thereof. Hence, the presented analysis provides a quantitative substantiation for the separate collection and treatment of specific waste streams in order to reduce the complexity of the mix of plastic types and allow for the more cost-efficient and higher quality recycling of plastics.

Measuring Waste Recyclability Level Using Convolutional Neural Network and Fuzzy Inference System

This paper presents a hybrid model that is used to measure the waste recyclability level using a convolutional neural network (CNN) and fuzzy inference system (FIS; WRL-CNNFIS). The proposed system uses waste images to train a multilayer convolutional neural network to extract the most relevant features that were used in a rule-based fuzzy system to give an accurate percentage of the recyclability level of these images. The proposed model did overcome many challenges in transfer learning models alone, like overfitting and low accuracy. The use of fuzzy rules, improved the performance even with a small data set, Results have shown the effectiveness of the proposed model in terms of all four metrics: accuracy, precision, recall, and F1 score. The performance was measured under two testing scenarios. For all evaluation measurement, in all experiments the validation was conducted using the cross validation in the last step. The proposed approach is a robust and consistent approach for classifying organic and recyclable waste types. WRL-CNNFIS has achieved accuracy rate of more than 98%.

A Service-Learning Based Computers Reuse Program

Higher Education Institutions are facing a challenging situation: how to introduce concepts such as Sustainability or the Circular Economy into their curricula. This study presents how to organize a Computer Reuse Program, an educational proposal for the Reuse, Repair, Refurbishment, Remanufacture and Recycling of computers into a Curriculum and a case study. The proposal is based in the Service-Learning methodology, by which students develop technical and professional skills while undertaking a project that has a direct and real impact on society. Students work on old or broken computers provided by donors, thereby acquiring technical skills. These now flawlessly functioning computers are donated to NGOs and other non-profit organizations, thus endowing the equipment with a much longer life as well as reducing e-waste, one of the fastest-growing waste streams in the world. As a case study, this paper presents the UPC Computer Reuse Program, carried out at Universitat Politècnica de Catalunya UPC-BarcelonaTech. Since the program started in 2004, some 2500 computers have been donated to 359 different organizations in 29 countries, and more than 5200 students have participated. The paper analyzes the impact of the program on society, on the reduction of e-waste, on the environment and on student awareness regarding social justice and sustainability.

Characterizing the Urban Mine—Simulation-Based Optimization of Sampling Approaches for Built-in Batteries in WEEE

Comprehensive knowledge of built-in batteries in waste electrical and electronic equipment (WEEE) is required for sound and save WEEE management. However, representative sampling is challenging due to the constantly changing composition of WEEE flows and battery systems. Necessary knowledge, such as methodologically uniform procedures and recommendations for the determination of minimum sample sizes (MSS) for representative results, is missing. The direct consequences are increased sampling efforts, lack of quality-assured data, gaps in the monitoring of battery losses in complementary flows, and impeded quality control of depollution during WEEE treatment. In this study, we provide detailed data sets on built-in batteries in WEEE and propose a non-parametric approach (NPA) to determine MSS. For the pilot dataset, more than 23 Mg WEEE (6500 devices) were sampled, examined for built-in batteries, and classified according to product-specific keys (UNUkeys and BATTkeys). The results show that 21% of the devices had battery compartments, distributed over almost all UNUkeys considered and that only about every third battery was removed prior to treatment. Moreover, the characterization of battery masses (BM) and battery mass shares (BMS) using descriptive statistical analysis showed that neither product- nor battery-specific characteristics are given and that the assumption of (log-)normally distributed data is not generally applicable. Consequently, parametric approaches (PA) to determine the MSS for representative sampling are prone to be biased. The presented NPA for MSS using data-driven simulation (bootstrapping) shows its applicability despite small sample sizes and inconclusive data distribution. If consistently applied, the method presented can be used to optimize future sampling and thus reduce sampling costs and efforts while increasing data quality.

Disassembly-based bill of materials data for consumer electronic products

Consumer electronic products have a complex life cycle, characterized by environmental, social, and economic impacts and benefits associated with their manufacturing, use, and disposal at end-of-life. Accurately analysing these trade-offs and creating sustainable solutions requires data about the materials and components that make up these devices. Such information is rarely disclosed by manufacturers and only exists in the open literature in disparate case study format. This study presents a comprehensive database of bill of material (BOM) data describing the mass of major materials and components contained in 95 unique consumer electronic products. Data are generated by product disassembly and physical characterization and then validated against external benchmarks in the literature. The study also contributes a reproducible framework for organizing BOM data so that they can be expanded as new products enter the market. These data will benefit researchers studying all aspects of electronics and sustainability, including material scarcity, product design, environmental life cycle assessment, electronic waste policy, and environmental health and safety.

Assessment of tetrabromobisphenol-A (TBBPA) content in plastic waste recovered from WEEE

Due to the variability of additives and polymer types used in electrical and electronic equipment (EEE), and in accordance with the European Directive 2012/19/EU, an implementation of sound management practices is necessary. This work focuses on assessing the content of tetrabromobisphenol-A (TBBPA) in acrylonitrile-butadiene-styrene (ABS), polypropylene (PP), polycarbonate (PC) and their polymer blends (i.e. PC/ABS). A total of 36 plastic housing samples originating from microwave ovens, electric irons, vacuum cleaners and DVD/CD players were subjected to microwave-assisted-extraction (MAE) and/or ultrasound-assisted-extraction (UAE). Maximum mean concentration values of TBBPA measured in DVD/CD players and vacuum cleaners ranged between 754-1146 μg/kg, and varied per polymer type, as follows: 510-2515 μg/kg in ABS and 55-3109 μg/kg in PP. The results indicated that MAE was more sufficient than UAE in the extraction of TBBPA from ABS. To optimize the UAE procedure, various solvents were tested. Higher amounts of TBBPA were obtained from ABS and PP using a binary mixture of a polar-non-polar solvent, isopropanol:n-hexane (1:1), whereas the sole use of isopropanol exhibited incomplete extraction.

Towards a high quality recycling of plastics from waste electrical and electronic equipment through separation of contaminated fractions

The aim of this study is to provide an evaluation of the recyclability of plastics derived from electrical equipment from contamination standpoint. A database was created to find trends in potentially toxic elements (PTEs) and bromine concentrations; in relation to unit's application, color, polymer type, and production date. For this study, 142 kg of plastics derived from waste electrical and electronic equipment, from the collection group 5, were analyzed. Less than 1.5 % of the analyzed material indicated hazardous characteristics due to their PTEs concentrations (following RoHS and REACH). Regarding the bromine (Br) content, larger quantities of plastics showed recycling incompatibility; 71 parts with total weight of 11 kg (8 %-wt) contained Br concentrations >2000 mg kg^-1. The highest average value of Pb, Cd, Hg and Cr combined falls under the application category 'tools', which was as well the trend in appliances from before 1990. The same trend was observed for Br and antimony (Sb) contents; high concentrations were found in appliances from the 'tools' category. This study concludes that plastics derived from colored appliances and appliances labeled as tools have to be evaluated before being sent for recycling, due to high contamination risks.

A comprehensive characterization of End-of-Life mobile phones for secondary material resources identification

In this paper a full recognition of the different materials and valuable metals constituting mobile phones was performed. To this aim, a sample of 20 end-of-life devices has been dismantled and quantitative and qualitative chemical composition of the individual components was determined. From dismantling operations, it was found that plastics, metals, electronic components, batteries and displays account for 33%, 11%, 23%, 24% and 9% respectively, as a weighted average. Plastic parts of each item were analyzed by spectroscopy and then classified according to the plastic polymer type; it was found that polymeric components of mobile phones were made of five polymers: acrylonitrile-butadienestyrene, polycarbonate, polyurethane, polymethylmethacrylate and silicone. Electronic parts were leached by a twofold aqua regia treatment and the metal composition was determined: 15 elements were identified with concentration >0.2%. On the basis of these results, some considerations about the recycling context of end-of-life mobile phones were performed.

Towards a more circular economy for WEEE plastics - Part B: Assessment of the technical feasibility of recycling strategies

This two paper series describes a method to develop and evaluate new recycling strategies for WEEE plastics. Part A presents a SWOT analysis that leads to five recycling strategies for the optimal integration of new dismantling based recycling processes for plastic components in an established post-shredder separation infrastructure. In this paper the technical feasibility of the strategies is demonstrated by means of LCD TV back cover housings. The component recycling is shown to produce recycled PC/ABS with phosphorous flame retardants suitable for direct re-application in electronic products. The high quality is characterized by a good mechanical and aesthetical properties as well as a recovered flammability. HIPS with brominated flame retardants was recycled to produce masterbatches. The technical feasibility of this strategy was proven by mechanical and flammability testing. However, the presence of deca-BDE requires this material to be incinerated. A combination of EU legislation research and forecasting shows that the origin of this flame retardant are TV models produced before 2008 and restricted concentrations still need to be expected for decades to come. Further, a blending strategy of HIPS/PPE is shown to improve the mechanical properties of post-shredder recycled HIPS. The evaluation of refeeding ABS/PMMA into the post-shredder recycling process of ABS indicates only partial compatibility. Further, complications due to density differences make this strategy more suitable for polymers that are already commercially recycled such as ABS and HIPS. Colour is identified as a key requirements that limits the use of WEEE plastics in high-quality products.

Computational Fluid Dynamics Modeling of Combustion Characteristics of a CH4/O2 Combustor in a Copper Anode Furnace

With the rapid depletion of high-yield copper mineral resources and the accumulation of secondary copper resources, the recycling of secondary copper is gaining popularity in the copper industry. A copper anode furnace, often used in copper recycling, usually relies on methane combustion to melt copper scraps. In this work, a computational fluid dynamics (CFD) model of pure oxy-methane combustion is established to investigate the combustion characteristics of the CH₄/O₂ combustor in the copper anode furnace. The model is validated by comparing the simulation results with experimental measurements. The effects on flame length and temperature distribution are investigated under various fuel velocities, oxidizer velocities, and oxidizer temperatures. The results indicate that flame length and temperature distribution increase as the fuel velocity and oxidizer temperature increase, and decrease with the increase in oxidizer velocity. The flame length and temperature distribution always show an increasing trend with the increasing equivalence ratio. Based on the recycling capacity of the copper anode furnace, this validated CFD model can be used to optimize the operation parameters for controlling flame length and temperature distribution.

Leveraging Circular Economy through a Methodology for Smart Service Systems Engineering

Product Service Systems (PSS) and Smart Services are powerful means for deploying Circular Economy (CE) goals in industrial practices, through dematerialization, extension of product lifetime and efficiency increase by digitization. Within this article, approaches from PSS design, Smart Service design and Model-based Systems Engineering (MBSE) are combined to form a Methodology for Smart Service Architecture Definition (MESSIAH). First, analyses of present system modelling procedures and systems modelling notations in terms of their suitability for Smart Service development are presented. The results indicate that current notations and tools do not entirely fit the requirements of Smart Service development, but that they can be adapted in order to do so. The developed methodology includes a modelling language system, the MESSIAH Blueprinting framework, a systematic procedure and MESSIAH CE, which is specifically designed for addressing CE strategies and practices. The methodology was validated on the example of a Smart Sustainable Street Light System for Cycling Security (SHEILA). MESSIAH proved useful to help Smart Service design teams develop service-driven and robust Smart Services. By applying MESSIAH CE, a sustainable Smart Service, which addresses CE goals, has been developed.

Biotechnological strategies for the recovery of valuable and critical raw materials from waste electrical and electronic equipment (WEEE) - A review

Critical raw materials (CRMs) are essential in the development of novel high-tech applications. They are essential in sustainable materials and green technologies, including renewable energy, emissionfree electric vehicles and energy-efficient lighting. However, the sustainable supply of CRMs is a major concern. Recycling end-of-life devices is an integral element of the CRMs supply policy of many countries. Waste electrical and electronic equipment (WEEE) is an important secondary source of CRMs. Currently, pyrometallurgical processes are used to recycle metals from WEEE. These processes are deemed imperfect, energy-intensive and non-selective towards CRMs. Biotechnologies are a promising alternative to the current industrial best available technologies (BAT). In this review, we present the current frontiers in CRMs recovery from WEEE using biotechnology, the biochemical fundamentals of these bio-based technologies and discuss recent research and development (R&D) activities. These technologies encompass biologically induced leaching (bioleaching) from various matrices,biomass-induced sorption (biosorption), and bioelectrochemical systems (BES).

Product Family Approach in E-Waste Management: A Conceptual Framework for Circular Economy

As the need for a more circular model is being increasingly pronounced, a fundamental change in the end-of-life (EoL) management of electrical and electronic products (e-products) is required in order to prevent the resource losses and to promote the reuse of products and components with remaining functionality. However, the diversity of product types, design features, and material compositions pose serious challenges for the EoL managers and legislators alike. In order to address these challenges, we propose a framework that is based on the ‘product family’ philosophy, which has been used in the manufacturing sector for a long time. For this, the product families can be built based on intrinsic and extrinsic attributes of e-products as well as of the EoL management system. Such an approach has the potential to improve the current EoL practices and to support designers in making EoL thinking operational during the product design stage. If supported by a better EoL collection, presorting and testing platform, and a family-centric approach for material recovery, such a framework carries the potential to avoid the losses occurring in today’s e-waste management system. This, in turn, could facilitate a smooth transition towards a circular model for the electrical and electronic industry.

Selective separation of ABS/PC containing BFRs from ABSs mixture of WEEE by developing hydrophilicity with ZnO coating under microwave treatment

This study reports a simple and facile method to separate plastic wastes of acrylonitrile-butadiene-styrene (ABS) and ABS-based plastics (blends of ABS) in waste electronic and electrical equipment (WEEE) by froth flotation after inducing hydrophilization by ZnO coating under microwave treatment. ABS-based plastics containing brominated flame retardants (BFRs) can release hazardous substances, such as hydrogen bromide and brominated dioxins, during disposal or recycling activities. ABS and ABS-based plastics are typical styrene plastics with similar properties and it is, therefore, difficult to separate them selectively for recycling. We used 2-min microwave treatment to rearrange and change the molecular mobility on the surface of the ZnO-coated ABS with increased hydrophilic surfaces, which eased the selective separation of the ABS/polycarbonate (PC) blend containing BFRs from the remaining plastics. Therefore, the combined ZnO coating and microwave treatments can facilitate the selective separation of ABS/PC blend plastics with a recovery and purity of 100% and 91.7%, respectively, in a short flotation time of 2min. Based on these findings, the combination of ZnO coating-microwave treatment and froth flotation can be applied for the selective separation of ABS-based plastics, leading to improved plastic recycling quality.

Waste Printed Circuit Board (PCB) Recycling Techniques

With the development of technologies and the change of consumer attitudes, the amount of waste electrical and electronic equipment (WEEE) is increasing annually. As the core part of WEEE, the waste printed circuit board (WPCB) is a dangerous waste but at the same time a rich resource for various kinds of materials. In this work, various WPCB treatment methods as well as WPCB recycling techniques divided into direct treatment (landfill and incineration), primitive recycling technology (pyrometallurgy, hydrometallurgy, biometallurgy and primitive full recovery of NMF-non metallic fraction), and advanced recycling technology (mechanical separation, direct use and modification of NMF) are reviewed and analyzed based on their advantages and disadvantages. Also, the evaluation criteria are discussed including economic, environmental, and gate-to-market ability. This review indicates the future research direction of WPCB recycling should focus on a combination of several techniques or in series recycling to maximize the benefits of process.

Stocks, Flows, and Distribution of Critical Metals in Embedded Electronics in Passenger Vehicles

One of the major applications of critical metals (CMs) is in electrical and electronic equipment (EEE), which is increasingly embedded in other products, notably passenger vehicles. However, recycling strategies for future CM quantities in end-of-life vehicles (ELVs) are poorly understood, mainly due to a limited understating of the complexity of automotive embedded EEE. We introduce a harmonization of the network structure of automotive electronics that enables a comprehensive quantification of CMs in all embedded EEE in a vehicle. This network is combined with a material flow analysis along the vehicle lifecycle in Switzerland to quantify the stocks and flows of Ag, Au, Pd, Ru, Dy, La, Nd, and Co in automotive embedded EEE. In vehicles in use, we calculated 5_-2⁺³ t precious metals in controllers embedded in all vehicle types and 220_-60⁺⁹⁰ t rare earth elements (REE); found mainly in five electric motors: alternator, starter, radiator-fan and electronic power steering motor embedded in conventional passenger vehicles and drive motor/generator embedded in hybrid and electric vehicles. Dismantling these devices before ELV shredding, as well as postshredder treatment of automobile shredder residue may increase the recovery of CMs from ELVs. Environmental and economic implications of such recycling strategies must be considered.

Liberation of Printed Circuit Assembly (PCA) and dust generation in relation to mobile phone design in a size reduction process

Complex electronic devices entering our recycling systems often generate losses in the whole treatment chain. For better liberation, crucial for the mechanical separation process, the devices are crushed which also generates dusts that are not recovered. This study investigated the relation between the liberation of Printed Circuit Assembly (PCA) and dust generation in the crushing process of two different types of mobile phone samples. The results revealed that the overall PCA grade in both samples was approximately 70% with around 3.4% dust generation. However, the liberation distribution of PCAs differed between mobile phones resulting in better distribution for sophisticated mobile phones due among other things to the initial size of the phones. Further, the dust fractions comprised both noble and valuable metals but also contaminants that need to be taken into account when further processing is planned. A higher gold concentrate was detected in dusts from regular phones since the protective plastic casing crushed more easily thus exposing the PCA surface for grinding.

High-quality collection and disposal of WEEE: Environmental impacts and resultant issues

Life cycle assessment of the collection, transport and recycling of various types of waste electrical and electronic equipment (WEEE) in Norway shows that small amounts of critical materials (refrigerants, precious/trace metals) are vital for the overall environmental accounts of the value chains. High-quality recycling ensures that materials and energy are effectively recovered from WEEE. This recovery means that responsible waste handling confers net environmental benefits in terms of global warming potential (GWP), for all types of WEEE analysed. For refrigeration equipment, the potential reduction of GWP by high-quality recycling is so large as to be of national significance. For all waste types, the magnitude of the net benefit from recovering materials and energy exceeds the negative consequences of irresponsible disposal. One outcome of this may be widespread misunderstanding of the need for recycling. Furthermore, framing public communication on recycling in terms of avoiding negative consequences, as is essentially universal, may not convey an appropriate message. The issue is particularly important where the consumer regards products as relatively disposable and environmentally benign, and/or where the "null option" of retaining the product at end-of-life is especially prevalent. The paper highlights the implications of all these issues for policy-makers, waste collectors and recyclers, and consumers.

Sustainable and Selective Separation of PVC and ABS from a WEEE Plastic Mixture Using Microwave and/or Mild-Heat Treatment with Froth Flotation

This study reports simple, selective, and sustainable separation of chlorinated plastic (polyvinyl chloride, PVC) and acrylonitrile butadiene styrene (ABS) containing brominated flame retardants (BFRs) from mixed waste electrical and electronic equipment (WEEE) plastics using microwave and/or mild-heat treatment. Microwave treatment after plastic coating with powdered activated carbon (PAC) selectively increased the hydrophilicity of the PVC surface, which facilitated PVC separation (100% recovery and purity) from the WEEE plastic mixture under the optimum flotation conditions. A further mild-heat treatment for 100 s facilitated selective separation with the highest recovery and purity (100%) of PAC-coated ABS containing BFRs from the remaining plastic mixture due to selective formation of a twisted structure with a lower density than water and the untreated ABS. Mild-heat treatment only of PAC-coated WEEE plastic mixture resulted in successful recovery of (100%) the ABS and PVC. However, the recovered PVC had slightly reduced purity (96.8%) as compared to that obtained using the combined heat and microwave treatments. The combination of both treatments with flotation facilitated selective and sustainable separation of PVC and ABS from WEEE plastics to improve their recycling quality.

Disassembly properties and material characterisation of household small waste electric and electronic equipment

This paper is focused on characterising small waste electric and electronic equipment, specifically small household appliances, from two different points of views: disassembly properties and material identification. The sample for this characterisation was obtained from a selective collection campaign organised in Castellón de la Plana (Spain). A total amount of 833.7kg (749 units) of small waste electric and electronic equipment was collected, of which 23.3% by weight and 22.4% by units belonged to the subcategory household equipment. This subcategory, composed of appliances such as vacuum cleaners, toasters, sandwich makers, hand blenders, juicers, coffee makers, hairdryers, scales, irons and heaters, was first disassembled in order to analyse different aspects of the disassembly process for each equipment type: type of joints, ease of identification of materials, ease of access to joints for extracting components, ease of separation of components from the whole, uniformity of tools needed for the disassembly process and possibility of reassembly after disassembly. Results show that the most common joints used in these equipment types are snap-fits and screws, although some permanent joints have also been identified. Next, the material composition of each component of each appliance belonging to each equipment type was identified visually and with additional mechanical trials and testing. It can be observed that plastic and electric/electronic components are present in all the equipment types analysed and are also the material fractions that appear with higher percentages in the material composition: 41.1wt% and 39.1wt% for the plastic fraction and electric/electronic components, respectively. The most common plastics are: polypropylene (PP), acrylonitrile butadiene styrene (ABS) and polycarbonate (PC), while the most common electric/electronic components are: cable, plug and printed circuit boards. Results also show that disassembly properties and material characterisation vary widely from one equipment type to another.

Prospective analysis of the flows of certain rare earths in Europe at the 2020 horizon

This paper proposes a forecast of certain rare earth flows in Europe at the 2020 horizon, based on an analysis of trends influencing various actors of the rare earth industry along the value chain. While 2020 is indicated as the forecast horizon, the analysis should be considered as more representative of the next decade. The rare earths considered here are used in applications that are important for a low-carbon energy transition and/or have a significant recycling potential: NdFeB magnets (Pr, Nd, Dy), NiMH batteries (Pr, Nd) and fluorescent lamp phosphors (Eu, Tb, Y). An analysis of major trends affecting the rare earth industry in Europe along the value chain (including extraction, separation, fabrication, manufacture, use and recycling), helps to build a scenario for a material flow analysis of these rare earths in Europe. The scenario assumes in particular that during the next decade, there exists a rare earth mine in production in Europe (with Norra Kärr in Sweden as a most likely candidate) and also that recycling is in line with targets proposed in recent European legislation. Results are presented in the form of Sankey diagrams which help visualize the various flows for the three applications. For example, calculations forecast flows from extraction to separation of Pr, Nd and Dy for magnet applications in Europe, on the order of 310 tons, 980 tons and 80 tons rare earth metal resp., while recycled flows are 35 tons, 110 tons and 30 tons resp. Calculations illustrate how the relative contribution of recycling to supply strongly depends on the situation with respect to demand. Considering the balance between supply and demand, it is not anticipated any significant shortage of rare earth supply in Europe at the 2020 horizon, barring any new geopolitical crisis involving China. For some heavy rare earths, supply will in fact largely outweigh demand, as for example Europium due to the phasing out of fluorescent lights by LEDs.

Mobile phone waste management and recycling: Views and trends

There is an enormous growth in mobile phone consumption worldwide which leads to generation of a large volume of mobile phone waste every year. The aim of this review is to give an insight on the articles on mobile phone waste management and recycling, published in scientific journals, major proceedings and books from 1999 to 2015. The major areas of research have been identified and discussed based on available literature in each research topic. It was observed that most of these articles were published during the recent years, with the number of articles increasing yearly. Material recovery and review on management options of waste are found to be the leading topics in this area. Researchers have proved that economically viable refurbishing or recycling of such waste is possible in an environmentally friendly manner. However, the literatures indicate that without proper consumer awareness, a recycling system cannot perform to its maximum efficiency. The methodologies followed and analytical techniques employed by the researchers to attain their objectives have been discussed. The graphical representations of available literature on current topic with respect to year of publication, topics and location have also been explored.

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.

Characterisation and materials flow management for waste electrical and electronic equipment plastics from German dismantling centres

Waste electrical and electronic equipment is a complex waste stream and treatment options that work for one waste category or product may not be appropriate for others. A comprehensive case study has been performed for plastic-rich fractions that are treated in German dismantling centres. Plastics from TVs, monitors and printers and small household appliances have been characterised extensively. Based on the characterisation results, state-of-the-art treatment technologies have been combined to design an optimised recycling and upgrade process for each input fraction. High-impact polystyrene from TV casings that complies with the European directive on the restriction of hazardous substances (RoHS) was produced by applying continuous density separation with yields of about 60%. Valuable acrylonitrile butadiene styrene/polycarbonate can be extracted from monitor and printer casings by near-infrared-based sorting. Polyolefins and/or a halogen-free fraction of mixed styrenics can be sorted out by density separation from monitors and printers and small household appliances. Emerging separation technologies are discussed to improve recycling results.

An in-depth literature review of the waste electrical and electronic equipment context: trends and evolution

The consumption of electrical and electronic equipment (EEE) is continuously increasing worldwide and, consequently, so is the amount of waste electrical and electronic equipment (WEEE) it generates at its end-of-life. In parallel to this growth, legislation related to this issue has been passed in different countries with the aim of improving the management of WEEE. In order to raise awareness about the situation in which the generation, composition, management or final treatment of this kind of waste currently finds itself, an extensive number of articles have been published around the world. The aim of this paper is to define and analyse the main areas of research on WEEE by offering a broader analysis of the relevant literature in this field published between 1992 and August 2014. The literature researched comprises 307 articles, which are analysed according to the topic they focus on (WEEE management, WEEE generation, WEEE characterisation, social aspects of WEEE, re-use of EEE or economic aspects of WEEE). In addition, a deeper analysis is also presented, which takes into account the temporal evolution (globally and by topic), location of the study, categories and subcategories analysed, etc.

Waste electrical and electronic equipment management in Botswana: Prospects and challenges

The management of waste electronic and electrical equipment (WEEE) is a major challenge in developing and transition countries. The paper investigates recent strategies to manage this waste stream in an environmentally sound way. Obsolete electrical and electronic equipment (EEE) are a complex waste category containing both hazardous and valuable substances. Many countries and regions in the world are undertaking extensive scientific research to plan and develop effective collection and treatment systems for end-of-life EEE. In developing countries such as Botswana, effective strategies that cover all stages throughout the lifecycle of products, particularly at the end-of-life, still lag behind. Infrastructure, pre-processing, and end-processing facilities and innovative technologies for end-of-life management of e-waste are noticeably absent due to lack of investment and high costs of its management. The objective of the paper is to present the e-waste situation in Botswana, highlighting (a) measures taken in the form of legislative and policy regulations; (b) existing practices to manage e-waste; and (c) effective solutions for e-waste management in emerging economies. Studies from other countries on e-waste management issues provided insights on the "best" technical and logistical pre-processing and end-processing strategies to treat hazardous waste. The paper also highlights key societal factors that affect successful implementation of cost-effective collection and value recovery of end-of-life EEE. These include unavailability of national "e-waste policy," absence of formal take-back system, absence of financing and subsidies, inadequate source separation programmes, absence of technical and logistical integration of pre-processing and end-processing facilities, and limited infrastructure and access to technologies and investment. Effective strategies such as an "integrated approach" (mixed options), access to technologies, establishment of pre-processing and end-processing facilities and optimization of logistics, optimizing diversion of e-waste from disposal sites, and investment in e-waste are suggested to manage this complex waste stream in an environmentally sound way.

Recycling-oriented characterization of plastic frames and printed circuit boards from mobile phones by electronic and chemical imaging

This study characterizes the composition of plastic frames and printed circuit boards from end-of-life mobile phones. This knowledge may help define an optimal processing strategy for using these items as potential raw materials. Correct handling of such a waste is essential for its further "sustainable" recovery, especially to maximize the extraction of base, rare and precious metals, minimizing the environmental impact of the entire process chain. A combination of electronic and chemical imaging techniques was thus examined, applied and critically evaluated in order to optimize the processing, through the identification and the topological assessment of the materials of interest and their quantitative distribution. To reach this goal, end-of-life mobile phone derived wastes have been systematically characterized adopting both "traditional" (e.g. scanning electronic microscopy combined with microanalysis and Raman spectroscopy) and innovative (e.g. hyperspectral imaging in short wave infrared field) techniques, with reference to frames and printed circuit boards. Results showed as the combination of both the approaches (i.e. traditional and classical) could dramatically improve recycling strategies set up, as well as final products recovery.

Printed circuit boards: a review on the perspective of sustainability

Modern life increasingly requires newer equipments and more technology. In addition, the fact that society is highly consumerist makes the amount of discarded equipment as well as the amount of waste from the manufacture of new products increase at an alarming rate. Printed circuit boards, which form the basis of the electronics industry, are technological waste of difficult disposal whose recycling is complex and expensive due to the diversity of materials and components and their difficult separation. Currently, printed circuit boards have a fixing problem, which is migrating from traditional Pb-Sn alloys to lead-free alloys without definite choice. This replacement is an attempt to minimize the problem of Pb toxicity, but it does not change the problem of separation of the components for later reuse and/or recycling and leads to other problems, such as temperature rise, delamination, flaws, risks of mechanical shocks and the formation of "whiskers". This article presents a literature review on printed circuit boards, showing their structure and materials, the environmental problem related to the board, some the different alternatives for recycling, and some solutions that are being studied to reduce and/or replace the solder, in order to minimize the impact of solder on the printed circuit boards.

A review of the recycling of non-metallic fractions of printed circuit boards

There is a big waste generation nowadays due to the growing demand for innovation and the fact that more and more products have a reduced lifetime, increasing the volume of dumps and landfills. Currently, one of the segments of large volume is the technology waste, which reflects on the printed circuit boards (PCBs) that are the basis of the electronics industry. This type of waste disposal is difficult, given that recycling is complex and expensive, because of the diversity of existing materials and components, and their difficult separation process. Regarding the material involved in PCBs, there are metal fractions (MFs) and non-metallic fractions (NMFs), of which the recycling of NMFs is one of the most important and difficult processes, because they amount to about 70% of the weight of the PCB’s waste. In the present paper, a literature review of the recycling of non-metallic fractions (NMFs) has been carried out, showing different studies and guidelines regarding this type of recycling, emphasizing that this type of waste still lacks for further application.

Data availability and the need for research to localize, quantify and recycle critical metals in information technology, telecommunication and consumer equipment

The supply of critical metals like gallium, germanium, indium and rare earths elements (REE) is of technological, economic and strategic relevance in the manufacturing of electrical and electronic equipment (EEE). Recycling is one of the key strategies to secure the long-term supply of these metals. The dissipation of the metals related to the low concentrations in the products and to the configuration of the life cycle (short use time, insufficient collection, treatment focusing on the recovery of other materials) creates challenges to achieve efficient recycling. This article assesses the available data and sets priorities for further research aimed at developing solutions to improve the recycling of seven critical metals or metal families (antimony, cobalt, gallium, germanium, indium, REE and tantalum). Twenty-six metal applications were identified for those six metals and the REE family. The criteria used for the assessment are (i) the metal criticality related to strategic and economic issues; (ii) the share of the worldwide mine or refinery production going to EEE manufacturing; (iii) rough estimates of the concentration and the content of the metals in the products; (iv) the accuracy of the data already available; and (v) the occurrence of the application in specific WEEE groups. Eight applications were classified as relevant for further research, including the use of antimony as a flame retardant, gallium and germanium in integrated circuits, rare earths in phosphors and permanent magnets, cobalt in batteries, tantalum capacitors and indium as an indium-tin-oxide transparent conductive layer in flat displays.

Recovering metallic fractions from waste electrical and electronic equipment by a novel vibration system

The need to recover and recycle valuable resources from Waste Electrical and Electronic Equipment (WEEE) is of growing importance as increasing amounts are generated due to shorter product life cycles, market expansions, new product developments and, higher consumption and production rates. The European Commission (EC) directive, 2002/96/EC, on WEEE became law in UK in January 2007 setting targets to recover up to 80% of all WEEE generated. Printed Wire Board (PWB) and/or Printed Circuit Board (PCB) is an important component of WEEE with an ever increasing tonnage being generated. However, the lack of an accurate estimate for PCB production, future supply and uncertain demands of its recycled materials in international markets has provided the motivation to explore different approaches to recycle PCBs. The work contained in this paper focuses on a novel, dry separation methodology in which vertical vibration is used to separate the metallic and non-metallic fractions of PCBs. When PCBs were comminuted to less than 1mm in size, metallic grades as high as 95% (measured by heavy liquid analysis) could be achieved in the recovered products.

Proposal of a new model to improve the collection of small WEEE: a pilot project for the recovery and recycling of toys

A new collection model was designed and tested in Catalonia (Spain) to foster the separate collection and recycling of electrical and electronic toys, with the participation of selected primary and secondary schools, as well as waste collection points and municipalities. This project approach is very original and important because small household WEEE has low rates of collection (16-21% WEEE within the EU or 5-7% WEEE in Spain) and no research on new approaches to enhance the collection of small WEEE is found in the literature. The project was successful in achieving enhanced toys collection and recycling rates, which went up from the national Spanish average of 0.5% toys before the project to 1.9 and 6% toys during the two project years, respectively. The environmental benefits of the campaign were calculated through a life-cycle approach, accounting for the avoided impact afforded by the reuse of the toys and the recycling of the valuable materials contained therein (such as metals, batteries and circuit boards) and subtracting the additional environmental burdens associated with the establishment of the collection campaign.

Composition of plastics from waste electrical and electronic equipment (WEEE) by direct sampling

This paper describes a direct analysis study carried out in a recycling unit for waste electrical and electronic equipment (WEEE) in Portugal to characterize the plastic constituents of WEEE. Approximately 3400 items, including cooling appliances, small WEEE, printers, copying equipment, central processing units, cathode ray tube (CRT) monitors and CRT televisions were characterized, with the analysis finding around 6000 kg of plastics with several polymer types. The most common polymers are polystyrene, acrylonitrile-butadiene-styrene, polycarbonate blends, high-impact polystyrene and polypropylene. Additives to darken color are common contaminants in these plastics when used in CRT televisions and small WEEE. These additives can make plastic identification difficult, along with missing polymer identification and flame retardant identification marks. These drawbacks contribute to the inefficiency of manual dismantling of WEEE, which is the typical recycling process in Portugal. The information found here can be used to set a baseline for the plastics recycling industry and provide information for ecodesign in electrical and electronic equipment production.

Practicalities of individual producer responsibility under the WEEE directive: experiences in Germany

In theory, individual producer responsibility (IPR) creates incentives for 'design-for-recycling'. Yet in practice, implementing IPR is challenging, particularly if applied to waste electric and electronic equipment. This article discusses different options for implementing IPR schemes under German WEEE legislation. In addition, practical aspects of a German 'return share' brand sampling scheme are examined. Concerning 'new' WEEE put on the market after 13 August 2006, producers in Germany can choose between two different methods of calculating take-back obligations. These can be determined on the basis of 'return shares' or 'market shares'. While market shares are regularly monitored by a national clearing house, the 'return share' option requires sampling and sorting of WEEE. Herein it is shown that the specifics of the German WEEE take-back scheme require high sample sizes and multi-step test procedures to ensure a statistically sound sampling approach. Since the market share allocation continues to apply for historic waste, producers lack incentives for choosing the costly brand sampling option. However, even return share allocation might not imply a decisive step towards IPR, as it merely represents an alternative calculation of market shares. Yet the fundamental characteristics of the German take-back system remain unchanged: the same anonymous mix of WEEE goes to the same treatment operations.

Application of material flow analysis to estimate the efficiency of e-waste management systems: the case of Lithuania

Electrical and electronic equipment (EEE) has penetrated everyday life. The EEE industry is characterized by a rapid technological change which in turn prompts consumers to replace EEE in order to keep in step with innovations. These factors reduce an EEE life span and determine the exponential growth of the amount of obsolete EEE as well as EEE waste (e-waste). E-waste management systems implemented in countries of the European Union (EU) are not able to cope with the e-waste problem properly, especially in the new EU member countries. The analysis of particular e-waste management systems is essential in evaluation of the complexity of these systems, describing and quantifying the flows of goods throughout the system, and all the actors involved in it. The aim of this paper is to present the research on the regional agent based material flow analysis in e-waste management systems, as a measure to reveal the potential points for improvement. Material flow analysis has been performed as a flow of goods (EEE). The study has shown that agent-based EEE flow analysis incorporating a holistic and life cycle thinking approach in national e-waste management systems gives a broader view to the system than a common administrative one used to cover. It helps to evaluate the real efficiency of e-waste management systems and to identify relevant impact factors determining the current operation of the system.

Environmental issues and management strategies for waste electronic and electrical equipment

Issues surrounding the impact and management of discarded or waste electronic and electrical equipment (WEEE) have received increasing attention in recent years. This attention stems from the growing quantity and diversity of electronic and electrical equipment (EEE) used by modern society, the increasingly rapid turnover of EEE with the accompanying burden on the waste stream, and the occurrence of toxic chemicals in many EEE components that can pose a risk to human and environmental health if improperly managed. In addition, public awareness of the WEEE or "e-waste" dilemma has grown in light of popular press features on events such as the transition to digital television and the exportation of WEEE from the United States and other developed countries to Africa, China, and India, where WEEE has often not been managed in a safe manner (e.g., processed with proper safety precautions, disposed of in a sanitary landfill, combusted with proper air quality procedures). This paper critically reviews current published information on the subject of WEEE. The definition, magnitude, and characteristics of this waste stream are summarized, including a detailed review of the chemicals of concern associated with different components and how this has changed and continues to evolve over time. Current and evolving management practices are described (e.g., reuse, recycling, incineration, landfilling). This review discusses the role of regulation and policies developed by governments, institutions, and product manufacturers and how these initiatives are shaping current and future management practices.

How are WEEE doing? A global review of the management of electrical and electronic wastes

This paper presents and critically analyses the current waste electrical and electronic equipment (WEEE) management practices in various countries and regions. Global trends in (i) the quantities and composition of WEEE; and (ii) the various strategies and practices adopted by selected countries to handle, regulate and prevent WEEE are comprehensively examined. The findings indicate that for (i), the quantities of WEEE generated are high and/or on the increase. IT and telecommunications equipment seem to be the dominant WEEE being generated, at least in terms of numbers, in Africa, in the poorer regions of Asia and in Latin/South America. However, the paper contends that the reported figures on quantities of WEEE generated may be grossly underestimated. For (ii), with the notable exception of Europe, many countries seem to be lacking or are slow in initiating, drafting and adopting WEEE regulations. Handling of WEEE in developing countries is typified by high rate of repair and reuse within a largely informal recycling sector. In both developed and developing nations, the landfilling of WEEE is still a concern. It has been established that stockpiling of unwanted electrical and electronic products is common in both the USA and less developed economies. The paper also identifies and discusses four common priority areas for WEEE across the globe, namely: (i) resource depletion; (ii) ethical concerns; (iii) health and environmental issues; and (iv) WEEE takeback strategies. Further, the paper discusses the future perspectives on WEEE generation, treatment, prevention and regulation. Four key conclusions are drawn from this review: global amounts of WEEE will continue unabated for some time due to emergence of new technologies and affordable electronics; informal recycling in developing nations has the potential of making a valuable contribution if their operations can be changed with strict safety standards as a priority; the pace of initiating and enacting WEEE specific legislation is very slow across the globe and in some cases non-existent; and globally, there is need for more accurate and current data on amounts and types of WEEE generated.

Property-close source separation of hazardous waste and waste electrical and electronic equipment--a Swedish case study

Through an agreement with EEE producers, Swedish municipalities are responsible for collection of hazardous waste and waste electrical and electronic equipment (WEEE). In most Swedish municipalities, collection of these waste fractions is concentrated to waste recycling centres where households can source-separate and deposit hazardous waste and WEEE free of charge. However, the centres are often located on the outskirts of city centres and cars are needed in order to use the facilities in most cases. A full-scale experiment was performed in a residential area in southern Sweden to evaluate effects of a system for property-close source separation of hazardous waste and WEEE. After the system was introduced, results show a clear reduction in the amount of hazardous waste and WEEE disposed of incorrectly amongst residual waste or dry recyclables. The systems resulted in a source separation ratio of 70 wt% for hazardous waste and 76 wt% in the case of WEEE. Results show that households in the study area were willing to increase source separation of hazardous waste and WEEE when accessibility was improved and that this and similar collection systems can play an important role in building up increasingly sustainable solid waste management systems.

Assessment of removal of components containing hazardous substances from small WEEE in Austria

Minimum treatment requirements for waste electrical and electronic equipment (WEEE) established by Directive 2002/96/EC provide for the removal of specific components containing hazardous substances. To date, no comparative analysis of removal rates has been undertaken. The present paper examines the state of de-pollution of sWEEE in Austrian treatment plants. The mass of selected components removed and the corresponding mass of hazardous substances is compared to estimated values for sWEEE input material. The results obtained reveal that components are only partly removed, featuring a high variation between components and plants assessed. The overall rate of removal ranged from 72% of the estimated value for batteries to 21% of the estimated value for liquid crystal panels. This implies the forwarding of substantial quantities of hazardous substances to mechanical treatment processes, particularly relevant in terms of dispersion of pollutants. Furthermore, easily releasable pollutants, such as Hg from LCD-backlights, Cd from batteries or highly contaminated dust in general, pose substantial health risks for plant workers. Low removal rates of printed circuit boards, batteries and toner cartridges also lead to a reduction in quantities of valuable recyclable materials (precious metals, plastics).