Waste Mobile Phones Research Articles

Characterization of end-of-life mobile phone printed circuit boards for its elemental composition and beneficiation analysis

ABSTRACT Globally, waste electrical and electronic equipment is one of the fastest-growing waste sectors. Mobile phones constitute the major portion of the telecommunication e-waste category. Over the years, waste mobile phones were considered as a potential source of secondary metals. This study aims to determine the physical and chemical composition of the discarded mobile phones and to evaluate its recovery potential. The printed circuit boards from the discarded (waste) mobile phones (MPCB) were collected and samples of different sizes 3 × 3 cm, 2 mm, 1 mm, 500 µm, and 150 µm were obtained after milling and sieving. Elemental composition revealed the presence of base metals, Cu, Zn, Fe, Ni, and Pb, in higher quantities with a significant amount of precious metals Au and Ag. Amount of base metals present in different MPCB size fractions was found in the order 3 × 3 cm > 2 mm > 1 mm > 500 µm >150 µm. The amount of precious metals like Ag and Au was found to be higher in large-sized MPCB fractions. FTIR studies declared the presence of polymers like ABS, PC, and HIPs in MPCB samples. TCLP tests for toxic metals revealed that MPCBs contained high concentrations of cadmium, lead, and mercury highlighting their hazardous potential. The ultimate analysis revealed that NMF has a GCV of 12.34 MJ/kg and a volatile content of 42.25%, which can be a potential source of energy that can be recovered through the gasification or pyrolysis process. Overall, the comprehensive characterization of waste MPCBs will systematically provide a better understanding of e-waste recycling processes for beneficiation purpose and sustainable resource utilization. Implications: A comprehensive characterization of waste mobile phone printed circuit boards for its elemental composition was performed. Mechanical treatment steps before MPCBs processing increased the exposure of metals resulting in a higher concentration of metals in acid-digested samples. The elemental analysis of MPCBs revealed that MPCBs possessed significant quantities of base and precious metals. The amount of precious metals like Ag and Au was also found in higher ranges in large-sized MPCB fractions, which elucidated fact to be considered in the pre-treatment process for metal recoveries. The high content of base and precious metals in waste mobile phones displayed their economic potential in the market. This new source may compensate for the escalating global demand for gold and silver. Results from the study indicated that MPCBs can serve as an excellent secondary source for various metals and as an efficient alternative fuel.

Analysis of the Efficiency of Various Waste Electrical and Electronic Equipment’s Collection Routes: A Case Study Focusing on Collection Route for Waste Mobile Phones in the Tohoku Area of Japan

Each year, more than 5 million Waste Mobile Phones (WMP) is generated in Japan. Since WMPs contain many rare metals and precious metals, it is essential to collect and recycle high-value metal resources from them effectively. Although multiple stakeholders have already developed WMP collection routes, these WMP collection routes’ current status is unclear. Furthermore, some WMP collection routes can only collect a small number of WMP, and so, their resource efficiency is low. This research aims to clarify each WMP collection route’s characteristics and evaluate their resource efficiency by conducting interview research on related stakeholders and the WMP dismantle experiment. The result shows that local government, authorized recyclers, and telecom carriers are the major stakeholders in collecting WMPs in Japan. To improve the WMP collection rate in cities with high population densities, using the local government’s collection route and installing an authorized recycler’s collection station is considered to be more effective. In cities with low population densities, the collection stations built by authorized recyclers are sufficient. The collection stations can also improve recycling behavior by offering points. Furthermore, the telecom carriers are encouraged to participate in the WMP collection business, but they should figure out a way to monitor the flow route of secondhand phones they exported and prompt the proper recycling of exported phones.

A probabilistic linguistic TODIM method considering cumulative probability-based Hellinger distance and its application in waste mobile phone recycling

The prosperity of online mobile phone recycling platforms has brought convenience to waste mobile phone recycling. This study aims to propose a novel decision-making method to evaluate the recycling channels of mobile phones in an uncertain environment using the probabilistic linguistic term set (PLTS) to represent uncertain information. Given that each PLTS is associated with a probability distribution, the differences of different PLTSs can be represented by comparing different probability distributions. The Hellinger distance is a widely-used index to measure the similarity of two probability distributions, but it cannot be directly used to express the semantic differences of PLTSs. In this regard, we introduce a cumulative probability-based Hellinger distance measure of PLTSs. Then, we propose an extension of TODIM (an acronym in Portuguese of Interactive and Multicriteria Decision Making) method considering the bounded rationality and psychology of decision-makers based on the proposed distance measure of PLTSs and a criterion weight determination method, the Simos-Roy-Figueira method. Finally, an illustrative example of evaluating the recycling channels of mobile phones is given with sensitive and comparative analyses, showing the efficiency of the proposed method. This method can also be applied to other various fields.

Comparative effectiveness of technical and regulatory innovations to reduce the burden of electronic waste

Waste Electrical and Electronic Equipment (WEEE) contain toxic metals and organic compounds, posing significant threats to human health and environmental quality. The risks vary according to equipment types and components that are influenced by innovations in technical configuration and regulatory policy. To disentangle the relative impacts of these influences in protecting health and environment, we investigated 13 WEEE and 14 components using a life cycle impact assessment procedure. Additionally, we analyzed Waste Mobile Phones (WMPs) and Waste Printed Circuit Boards (WPCBs) from computers manufactured between 2002 and 2010 to identify trends of toxic chemicals and potential adverse impacts associated with technological configurations and regulatory policies. The results show that, among WEEE, Cathode Ray Tube TV presented the highest carcinogenicity and non-carcinogenicity toxicity potential. Waste Air Conditioner posed the highest potential for ecotoxicity. Among electronic components, Waste Organic Light Emitting Diode displays posed the highest potential risk for carcinogenesis, whereas WPCBs from laptop computers posed the highest potential risk for non-cancer diseases. Solid State Drives posed the highest risks for ecotoxicity. Chromium was associated with risk of carcinogenesis and non-cancer diseases; whereas Al and Fe posed the highest potential for ecotoxicological impacts. During the period covered by the study, innovations in technological configurations and regulatory policies demonstrably reduced the potential toxicity risks posed by E-waste, attributable to reduction in the concentrations of toxic organic chemicals in WMPs/WPCBs. These results advance current understanding of strategies to reduce the risks posed by WEEE through coordination of technological innovations and regulatory policies.

A comparative analysis on recycling technologies for recovery of precious metals from waste mobile phones between China and Japan

A comparative analysis on recycling technologies for recovery of precious metals from waste mobile phones between China and Japan

Recovery of gold from waste mobile phone circuit boards and synthesis of nanomaterials using emulsion liquid membrane

In recent years, waste mobile phones have become popular as electronic waste due to the huge amount, serious pollution with improper disposal and high resource value. It is imperative to realize the recycling of resources in waste mobile phones. The application of emulsion liquid membrane in the recovery of gold and synthesis of nanomaterials from waste mobile phone printed circuit boards (WMPCBs) was studied. The components of the emulsion liquid membrane, effects of 7 factors on the extraction rate and the morphology of the synthesized nanomaterials were explored. The results show that it is possible to extract 99.79% of Au(III) from WMPCBs leachate with kerosene as diluent, Span80 as surfactant, methyl isobutyl ketone(MIBK) as carrier, ascorbic acid solution as stripping agent and liquid paraffin as membrane stabilizer. The external phase pH and the internal phase concentration had a greater influence on the extraction efficiency of Au(III) among 7 factors. The morphology of the synthesized product was affected by the concentration and type of the surfactant. It provides a new idea to connect recovery from waste with deep processing, extending the waste mobile phone recycling process chain and achieving high-value utilization of waste mobile phone secondary metal resource products.

Adsorption of gold from waste mobile phones by biochar and activated carbon in gold iodized solution

The application of laboratory-generated biochar and activated carbon adsorbents in gold iodized solution for the recycling of waste mobile phone printed circuit boards (WMPCBs) is investigated. This research aims to solve problems associated with the existing gold recovery technologies of WMPCBs. Currently, the disposal of WMPCBs is expensive, involves complex processes, and contributes to secondary pollution. In this study, laboratory-generated biochar is produced from corn straw, wheat straw, and wood chips by pyrolysis. The effects of factors on the adsorption efficiency are investigated, and the optimal operating conditions for biochar and activated carbon adsorption are determined. The following optimal parameters were found for activated carbon: temperature = 25 °C, particle size = 40–60 mesh, dosage = 0.05 g/10 mL, pH = 7, reaction time = 2 h, and oscillation frequency = 200 r/min. The adsorption efficiency reached 98.6%. For biochar, optimization involved: raw material from corn straw at a pyrolysis temperature = 700 °C, reaction time = 5 h, oscillation frequency = 200 r/min, pH = 3, dosage = 0.15 g/10 mL, and temperature = 50 °C. An adsorption efficiency of 98% was achieved. The two adsorbents were compared, and results demonstrated that the adsorption properties of the laboratory-generated biochar were slightly inferior to those of the activated carbon; however, they were similar. Biochar adsorption can reuse waste, which may not only solve the current problems related to WMPCB recycling, but can help to achieve a “win-win” situation of increased environmental protection and sustainable utilization of resources.

Pyrolytic Extraction and Characterization of Oil from Waste Recharge Scratch Card Papers for Industrial Application

Oil extracted from mobile phone waste recharge scratch cards paper by thermal pyrolysis was investigated. The oil was characterized by its physical, chemical, and functional groups present. The physicochemical characteristics of the oil determined are density 900 kg/m 3 , viscosity 1.5 mm2s-1, acid value 1.122 mgKOH/g, saponification value 98.175 mgKOH/g and iodine value 22.84 gI2 /100g. The pour point and flashpoints are -15 °C and 90 °C respectively. The Fourier Transform Infrared (FTIR) and Gas Chromatography-Mass Spectroscopy (GC-MS) revealed the presence of aldehydes, ketones, carboxylic acids, esters, alkenes alkanes, ethers, and phenol. This indicates that the oil has industrial applications in chemical, pharmaceutical, and biodiesel production.

Waste mobile phones: A survey and analysis of the awareness, consumption and disposal behavior of consumers in Australia

Electronic waste (e-waste) is one of the fastest-growing waste streams in the world and waste mobile phone (WMP) represents a significant portion of the stream. Consumer awareness, consumption, and disposal behavior are of importance to assist in the implementation the circular economy. In Australia, some 94% of the adult population has a mobile phone, and the only WMP collection and recycling program in the country - “MobileMuster” is operating under a voluntary scheme. This study reveals consumers' familiarity with the program, current consumption, and disposal behavior concerning mobile phones from a survey implemented in Sydney, Australia. In addition to descriptive analysis, statistical analysis (with the Chi-square test of independence and Multinomial Logistic Regression (MLR)) identifies factors that influenced the behaviors. The results show that only one-third of the respondents (32.42%) were aware of the program, and that there are 3.65 mobile phones in use per household, with an average possession lifespan of 3.17 years (including storage). Furthermore, there is a positive relationship between age and possession of mobile phones, and respondents discard or change their mobile phones while they were still working or repairable. The main reasons for disposing of mobile phones relate to them being either damaged/not functioning, lacking additional features, or having a backdated capacity. Storing (hoarding) mobile phones after active use was found predominant, and, more specifically, respondents aged 18–24 and 25–29 preferred to store their WMPs instead of taking them to collection points. The results reveal a need for environmental awareness-raising campaigns concerning WMPs recycling.

An integrated method of environmental analysis and system dynamics for management of mobile phone waste in Colombia

Global concern about electronic waste is growing due to the awareness of the consequences of inadequate management of this waste. The relationship between the accelerated development of telecommunications, globalization, economic growth, market conditions, environmental policies, the generation of electronic waste and the negative impact on the environment are of increasing interest for specialists in environmental science. This study aims to identify the relevant variables that influence electronic waste generation from discarded mobile phones, and the environmental implications of use and disposal of mobile telephones via a case study in Colombia, using a System Dynamics Model and the analysis of several various scenarios. The main determining factors were identified as mobile telephony line acquisitions, gross domestic product per capita, and the lifespan of mobile phones. These were shown to be the determining variables in the generation of waste of electrical and electronic equipment (WEEE) in the case of mobile phones in Colombia. Secondly, the amount of carbon dioxide emissions depends on the length of usage of the phones; in 2019 the actual waste generated by the disposal of mobile phones only contributed to 10.07 CO2 tons, compared to 102,245 tons generated by their usage.

Recycling gold from printed circuit boards gold-plated layer of waste mobile phones in “mild aqua regia” system

Traditional mechanical pretreatment and hydrometallurgy is the mainstream technology to recycle gold from waste printed circuit boards (PCBs). However, this method is cumbersome and often employs toxic/harsh chemicals. In the present study, gold was easily recycled from PCBs gold-plated layer of waste mobile phones (WMPs) in DMF-CuCl2-CaCl2 (DMF: dimethyl formamide) system what we call “mild aqua regia” without pretreatments or enrichment process, and the reaction system could be cyclic utilized. In such reaction system, gold could be recycled through leaching, precipitation and filtration. The reaction parameter optimization and reaction mechanisms were studied. Under the optimized conditions, the gold leaching rate and precipitation rate could reach over 99%. DMF plays a significant role in the leaching system. As a typical polar aprotic solvent, DMF cannot solvate Cl−. Thus, “Cl−” exists in a “naked state”, and it can easily react with Au. Besides, Au (III) could generate a complex through the complexation with DMF which could result in the redox potentials reduce and move the equilibrium to the Au leaching side. In summary, this study provided a fundamental basis as well as practical guidance for recovering precious metals from waste electrical and electronic equipment in an efficient manner.

Improving Hydrometallurgical Methods for Processing Tin-containing Electronic Waste

This article provides an overview of methods for processing electronic waste (mobile phones, smartphones, printed circuit boards). The possibility of extracting tin from the waste of printed circuit boards of mobile phones using hydrochloric acid is shown. Established that the deposition of tin from the productive solution occurs due to cementation - an electrochemical displacement reaction between a cementing metal (aluminum) and a cemented ion (tin). The possibility of intensification of the process using a vibrating installation is evaluated. An environmentally friendly and efficient method for processing tin-containing electronic waste is proposed.

What Drives Individuals to Dispose of Waste Mobile Phones? A Case Study in Indonesia

What Drives Individuals to Dispose of Waste Mobile Phones? A Case Study in Indonesia

Research on the Recycling Model of Waste Mobile Phone Based on System Dynamics

Mobile phone replacement is accelerating, the waste of mobile phone will not only cause a lot of waste of resources, after the simple landfill, the heavy metal infiltration into the soil, rivers and groundwater, but also soil and water pollution, bring serious harm to the animals and plants in contact with the soil and water. Efficient and standardized recycling of increasingly used mobile phones has become an urgent social problem to be solved. The emergence and continuous improvement of “Internte plus” recycling mode of used mobile phones make it possible to solve this problem. On the various influence factors of recovery efficiency, and their relations on the basis of the analysis of building “Internte plus” old cell phone recycling model of system dynamics model, using Vensim software to draw causal loop diagram and in view of the old cell phone recycling price, information security and logistics cost effect on the recovery mode efficiency is analyzed. Research shows that information security is the most important factor affecting the efficiency of “Internte plus” waste mobile phone recycling model.

Economic and environmental feasibility of hydrometallurgical process for recycling waste mobile phones

Waste mobile phones contain significant amounts of valuable metals and non-metallic materials. Consequently, the extraction of valuable materials from discarded phones, which is a more cost-effective method compared with primary mining, is an essential step for maximizing the recovery of secondary resources and minimizing e-waste pollution. We designed a green and efficient path for recovering valuable metals from waste mobile phones and explored its technical feasibility from both environmental and economic perspectives through life cycle assessment and revenue expenditure model.The results showed that the hydrometallurgical process had three characteristics of high recovery efficiency, significant environmental friendliness and economic feasibility. The recovery efficiencies of valuable metals were higher than 90%. Simultaneously, the return on investment was 29%, indicating that the recycling enterprises can achieve self-sufficiency. Thirdly, the environmental benefits were more significant compared to environmental damage released by hydrometallurgical process, representing a significant environmental friendliness. Within the overall recycling process, the core process made the greatest contribution to the environmental burden (45.38–65.68%), followed by manual disassembly process. A comparison of sub-processes in core process revealed that the mechanical crushing and sorting phase had the greatest environmental impacts that were primarily attributed to power consumption. Consequently, future research should focus on the development of energy-efficient pretreatment techniques and energy-saving equipment. The industrial practice of recycling waste mobile phones is still in its infancy in China. Future studies should also focus on the comparing different treatment processes, with the aim of providing technical support for the advancement of industry.

Acid Concentration: A Pre-requisite to Enhanced Metal Dissolution?

Technological advancement over the past decade has dramatically changed with new players such as China taking lead in information-technology and telecommunication market across the world. This development has seen surge in manufacturing industry output and consequently raw materials consumed by the sector. The environmental impact is however evident due to human interference with nature. E-waste is the fastest growing waste stream posing serious risk to fauna and flora due to numerous associated pollutants. In recycling industry, hydrometallurgy is widely adopted to recover metals from e-waste. Despite growing concern over secondary pollution associated with disposal, concentrated aqua regia is widely used to extract metals from e-waste. An ultrasonic bath enhanced dilute-acid leaching method was developed to recover copper and lead from waste mobile phone PCB. Repeatability and reproducibility showed 5.3% and 5.0% with respect to Cu while 9.8% and 6.3% RSD were recorded for lead. LOD and LOQ of 0.02 µg/g and 0.064 µg/g (Cu) and 0.082 µg/g and 0.312 µg/g (Pb) revealed that the method is suitable for dissolution of target metals from PCBs. Copper concentration of 332.98 mg/g recorded inferred that dilute aqua regia as much as concentrated has promising metal extraction power and thus could replace concentrated acids.

EPR Approach for Better Waste Management System for Mobile Phone Design in Indonesia

The influence of toxic electronic waste or electronic goods will occur if it is disposed of carelessly or managed in the wrong way. Open dumping and crude waste handling in landfill sites in Indonesia creating even more miserable situation (Damanhuri, 2010). Mobile phone or cell phone is considered as one of the fastest growing device in global society. More than 60% of global population have mobile phone, end even an individual may have more than one device. EPR could be taken as strategy in order to find better e-waste management of renewable and non-renewable resources specifically for Indonesia situation. EPR related action of WEEE in Indonesia is still uncertain especially for mobile phone product. It is observed that many used mobile phones are still disposed improperly by unauthorized party and may danger the people and environment. This study will observe how the mobile phone waste is handled by unorganized organization, how EPR is taken into account in mobile phone waste management system and what kind of solution that is based on EPR that could enhance environmentally save property of mobile phone design in the future, especially for Indonesia situation. It is important by considering Indonesian situation; the producers need to employ new design strategy not merely in order to meet regulation compliances but should extend the responsibility for better waste management friendly product design that is more suitable with Indonesia situation with minimum waste management infrastructure by involving End-of-Life Design Solution; better collection, separation, recyclability, reuse and ease of manufacture

Elemental Copper Recovery from e-Wastes Mediated with a Two-Step Bioleaching Process

Copper recovery from printed circuit boards (PCB) from waste mobile phones was investigated using a two-step bioleaching process. The method consists of a first step where Fe(II) ions are biologically oxidised to Fe(III) by Acidithiobacillus ferrooxidans. Later, Fe (III) ions are put in contact with the PCBs for copper solubilisation. At the conditions tested in the present work, the Fe(II) bio-oxidation (first step) was almost completed in 48 h. Two different methods (filtration and sedimentation) for biomass separation before the second step were tested. No significance differences between both separation methods were observed in terms of the overall process efficiency. In both cases, using 7.5 g/L of e-waste concentration, copper recovery of 95–100% were obtained in only 48 h. In order to test an inexpensive and environmental friendly method to recovery the copper from the leachate solution, cementation of Cu (II) with metallic iron was performed. The copper powder obtained had purity of 64.8%.

Toxicity evaluation of E-waste plastics and potential repercussions for human health

At present, waste mobile phone is considered to be one of the fastest-growing obsolete items in the stream of electronic waste (e-waste). Toxic substances such as heavy metals and brominated flame retardants (BFRs) have been widely added to plastics used in electrical and electronic equipment (EEE). The recent technological revolution in electronic appliances combined with high and growing consumption has caused a huge generation of waste electrical and electronic equipment (WEEE). Therefore, e-waste plastics are considered to be one of the fastest-growing waste streams globally. In this study, we examined the hazardous substances in the plastic components of waste mobile phones and then applied the USEtox life cycle impact assessment (LCIA) model to determine the impacts on human health. Specifically, various plastic parts separated from waste mobile phones (n = 20) were collected and then, we used standard tests to characterize the heavy metals and brominated flame retardants. The mean and range of the results are 2207.7 μg/kg (503.9–11569.9 μg/kg) for Pb, 91.6 μg/kg (8.8–464.4 μg/kg) for Cd, 13.7 μg/kg (1.6–58.9 μg/kg) for Be, 7203.3 μg/kg (117–69813 μg/kg) for Sb, 471.3 μg/kg (143.4–2351.3 μg/kg) for As, 1.5 mg/kg (2.1–12.5 mg/kg) for Hg and 523.7 mg/kg (27.1–3859 mg/kg) for Cr. The BFRs - a sum Polybrominated Biphenyls, Polybrominated Diphenyl Ethers and Hexabromocyclododecane - were not detected except for two samples, which was an average of 234.5 μg/kg for nona-BDE and deca-BDE. The total bromine (Br) concentration varied from 0 to 471 mg/kg (average value of 87.9 mg/kg) , while Tetrabromobisphenol A (TBBP-A) showed an average concentration of 214.3 μg/kg. In the case of potential human health risks, Hg contributed the major risk for carcinogens and non-cancer disease in the plastics, but the contribution of Pb was also significant. In the case of eco-toxicity, Cr posed the most significant risks in the plastics. Overall, the results show that the toxic substances are below the limit values of substances regulated in the RoHS Directive in China and Europe. However, the results of LCIA highlight the growing importance to avoid the open burning practices of e-waste plastics that contain Hg, Pb, Cr ad Sb. Additionally, the results set a new database for the e-waste plastics recycling industry and provide information for ecodesign in EEE production.

Comparative investigation on copper leaching efficiency from waste mobile phones using various types of ionic liquids

Recovery of valuable materials from waste mobile phones is significantly important with the rapid development of telecommunication industry. In this work, the comparative study was conducted on the copper leaching behaviors from waste mobile phones using various types of ionic liquids of [Bmim]Cl, [Emim]Cl, [Bmin][BF4], and [Bmim][PF6]. Effects of various operational factors, including ionic liquid type, additive agent, oxidizing agent, leaching time and temperature, on the copper leaching efficiency were investigated in detail. The results indicated that the copper leaching efficiency was improved with the addition of H2O2. Both considering leaching time and temperature, [Emim]Cl and [Bmim][BF6] were the ideal ionic liquids for high copper leaching rates under suitable operational conditions. The kinetics of copper leaching using the ionic liquids of [Emim]Cl and [Bmim][BF6] were clarified to determine the controlling model of copper leaching reaction. The results proved that the copper leaching reaction mainly depended on the controlling of solid membranes diffusion. The efficiencies of copper recovery by slurry electrolysis using various ionic liquid solutions were compared. The optimal copper recovery of 92.65% was obtained with the maximal current efficiency of 79.99% in the ionic liquid solution of CuSO4–NaCl–H2SO4-[Bmim][PF6]. The morphology analysis of copper deposit layer after slurry electrolysis proved better copper recovery performance using [Bmim][PF6] as ionic liquid.