ArticlePDF Available

Recycling of gold from electronics: Cost-effective use through ‘Design for Recycling’

DOI:10.1007/BF03214988
Authors:
Christian Hagelüken at Umicore
Christian Hagelüken
Christopher W Corti at COReGOLD Technology consultancy
Christopher W Corti
  • COReGOLD Technology consultancy
Download full-text PDFDownload full-text PDF
Read full-text
Download citation

Abstract and Figures

With over 300 tonnes of gold used in electronics each year, end-of-life electronic equipment offers an important recycling potential for the secondary supply of gold. With gold concentrations reaching 300-350 g/t for mobile phone handsets and 200-250 g/t for computer circuit boards, this “urban mine” is significantly richer than what is available in primary ores. However, the “mineralogy” in scrap products is much different than in the conventional ores in a gold mine: Up to 60 different elements are closely interlinked in complex assemblies and sub-assemblies, and this requires specialised metallurgical processes with extensive offgas treatment to recover gold and a wide range of other metals cost effectively and in an environmentally sound way. Moreover, the logistics to “excavate” and “haul” the scrap products to the concentrator and further to the smelter are much more challenging than in the primary supply chain. Currently, only a small portion of old products is collected and directed into state-of-the art recycling chains. Significant improvements are needed here to fully utilise this secondary metal resource. The importance of the gold content of scrap electronics to the economics of recovery of gold and many other valuable metals is not always appreciated and this impacts on the “design for recycling” approach in selecting materials for new products, particularly in the European Union where the WEEE Directive aims to provide a closed loop economy. With a lower carbon footprint than primary-mined gold, recycled gold represents an important “green” source. The challenges faced in recycling electronic scrap to achieve a closed loop economy are discussed.
Figures - uploaded by Christian Hagelüken
Author content
All figure content in this area was uploaded by Christian Hagelüken
Content may be subject to copyright.
0c960519b6a208c6f80000
00.pdf
Content uploaded by Christian Hagelüken
Author content
All content in this area was uploaded by Christian Hagelüken
Content may be subject to copyright.
Recycling of gold from electronics: Cost-effective use through ‘Design for Recyclin
g’.pdf
Available via license: CC BY-NC 2.0
Content may be subject to copyright.
A preview of the PDF is not available
... 165 However, in such a quick assessment it must be taken into account that the winning of new metal in a circular economy is not necessarily generally cheaper or more sustainable, due to the high requirement for a very narrow selectivity in the collection and processing of scrap. 87,89,133 This means that materials produced from scrap are only cheaper if the costs for their collection, separation, cleaning, and processing outweigh the costs of the primary synthesis, which is currently the case for only a few metallic alloys. This means that secondary synthesis can even have negative effects on sustainability, for instance if the scrap contains too many impurities or if its collection, sorting, and recovery (e.g., from highly dispersed or nanoscale mixed and integrated sources) cost more energy and CO 2 than what is gained from melting. ...
... The first problem is that most of the scrap available on the global market is not sorted by alloy, but it is highly mixed and thus contaminated material. 7,133,134 This is a particular problem for the mass market of aluminum alloys and practically all functional metallic materials (magnets, conductors, electrodes, catalysts, and so on), as these alloys are particularly sensitive to the intrusion and gradual accumulation of scrap-related impurities. ...
acs.chemrev.2c00799 with volume ID
Article
  • Mar 2023
Production of metals stands for 40% of all industrial greenhouse gas emissions, 10% of the global energy consumption, 3.2 billion tonnes of minerals mined, and several billion tonnes of by-products every year. Therefore, metals must become more sustainable. A circular economy model does not work, because market demand exceeds the available scrap currently by about two-thirds. Even under optimal conditions, at least one-third of the metals will also in the future come from primary production, creating huge emissions. Although the influence of metals on global warming has been discussed with respect to mitigation strategies and socio-economic factors, the fundamental materials science to make the metallurgical sector more sustainable has been less addressed. This may be attributed to the fact that the field of sustainable metals describes a global challenge, but not yet a homogeneous research field. However, the sheer magnitude of this challenge and its huge environmental effects, caused by more than 2 billion tonnes of metals produced every year, make its sustainability an essential research topic not only from a technological point of view but also from a basic materials research perspective. Therefore, this paper aims to identify and discuss the most pressing scientific bottleneck questions and key mechanisms, considering metal synthesis from primary (minerals), secondary (scrap), and tertiary (re-mined) sources as well as the energy-intensive downstream processing. Focus is placed on materials science aspects, particularly on those that help reduce CO2 emissions, and less on process engineering or economy. The paper does not describe the devastating influence of metal-related greenhouse gas emissions on climate, but scientific approaches how to solve this problem, through research that can render metallurgy fossil-free. The content is considering only direct measures to metallurgical sustainability (production) and not indirect measures that materials leverage through their properties (strength, weight, longevity, functionality).
View
... 165 However, in such a quick assessment it must be taken into account that the winning of new metal in a circular economy is not necessarily generally cheaper or more sustainable, due to the high requirement for a very narrow selectivity in the collection and processing of scrap. 87,89,133 This means that materials produced from scrap are only cheaper if the costs for their collection, separation, cleaning, and processing outweigh the costs of the primary synthesis, which is currently the case for only a few metallic alloys. This means that secondary synthesis can even have negative effects on sustainability, for instance if the scrap contains too many impurities or if its collection, sorting, and recovery (e.g., from highly dispersed or nanoscale mixed and integrated sources) cost more energy and CO 2 than what is gained from melting. ...
... The first problem is that most of the scrap available on the global market is not sorted by alloy, but it is highly mixed and thus contaminated material. 7,133,134 This is a particular problem for the mass market of aluminum alloys and practically all functional metallic materials (magnets, conductors, electrodes, catalysts, and so on), as these alloys are particularly sensitive to the intrusion and gradual accumulation of scrap-related impurities. ...
The Materials Science behind Sustainable Metals and Alloys
Article
  • Feb 2023
Production of metals stands for 40% of all industrial greenhouse gas emissions, 10% of the global energy consumption, 3.2 billion tonnes of minerals mined, and several billion tonnes of by-products every year. Therefore, metals must become more sustainable. A circular economy model does not work, because market demand exceeds the available scrap currently by about two-thirds. Even under optimal conditions, at least one-third of the metals will also in the future come from primary production, creating huge emissions. Although the influence of metals on global warming has been discussed with respect to mitigation strategies and socio-economic factors, the fundamental materials science to make the metallurgical sector more sustainable has been less addressed. This may be attributed to the fact that the field of sustainable metals describes a global challenge, but not yet a homogeneous research field. However, the sheer magnitude of this challenge and its huge environmental effects, caused by more than 2 billion tonnes of metals produced every year, make its sustainability an essential research topic not only from a technological point of view but also from a basic materials research perspective. Therefore, this paper aims to identify and discuss the most pressing scientific bottleneck questions and key mechanisms, considering metal synthesis from primary (minerals), secondary (scrap), and tertiary (re-mined) sources as well as the energy-intensive downstream processing. Focus is placed on materials science aspects, particularly on those that help reduce CO2 emissions, and less on process engineering or economy. The paper does not describe the devastating influence of metal-related greenhouse gas emissions on climate, but scientific approaches how to solve this problem, through research that can render metallurgy fossil-free. The content is considering only direct measures to metallurgical sustainability (production) and not indirect measures that materials leverage through their properties (strength, weight, longevity, functionality).
View
... The concept of design for recycling appeared in the 1990s, and its early applications were mainly in the fields of automobiles, furniture, and electric and electronic products [42][43][44][45]. For example, IBM recycled over 70 million pounds of computer equipment from 1994 to 1997, saving over $50 million through internal product reuse and bringing in another $5 million through the sale of recycled commodities [46]. ...
The Key to Solving Plastic Packaging Wastes: Design for Recycling and Recycling Technology
Article
Full-text available
  • Mar 2023
Confronted with serious environmental problems caused by the growing mountains of plastic packaging waste, the prevention and control of plastic waste has become a major concern for most countries. In addition to the recycling of plastic wastes, design for recycling can effectively prevent plastic packaging from turning into solid waste at the source. The reasons are that the design for recycling can extend the life cycle of plastic packaging and increase the recycling values of plastic waste; moreover, recycling technologies are helpful for improving the properties of recycled plastics and expanding the application market for recycled materials. This review systematically discussed the present theory, practice, strategies, and methods of design for recycling plastic packaging and extracted valuable advanced design ideas and successful cases. Furthermore, the development status of automatic sorting methods, mechanical recycling of individual and mixed plastic waste, as well as chemical recycling of thermoplastic and thermosetting plastic waste, were comprehensively summarized. The combination of the front-end design for recycling and the back-end recycling technologies can accelerate the transformation of the plastic packaging industry from an unsustainable model to an economic cycle model and then achieve the unity of economic, ecological, and social benefits.
View
... These activities are still carried out employing artisanal processes that are not regulated and where there is no control of the contaminants that result when this type of waste is subjected to high temperatures. Since WEEE contains a wide range of metals, it also contains organic compounds, which are generally toxic and potentially bioaccumulate, such as brominated flame retardants, polychlorinated dibenzo-p-dioxins, dibenzofurans, polybrominated diphenyl ethers, chlorinated dioxins, and polycyclic aromatics, which produce highly carcinogenic gases when burned [8,9]. ...
Base Metals Extraction from Printed Circuit Boards by Pressure Acid Leaching
Article
Full-text available
  • Jan 2023
Printed circuit boards (PCBs) are a valuable source of raw materials for metal recycling considering that base metal concentration analyses have confirmed that PCB powders are multimetallic in nature and contain high concentrations of Cu, Zn, Ni, and Fe. Given that minerals are not renewable resources, these metals can be recycled through hydrometallurgical processes. In this study, we determined that 2 M sulfuric acid, 0.55 MPa oxygen pressure, and a temperature of 90 °C represent the optimal conditions for leaching of Cu, Zn, and Ni of PCBs, obtaining the highest observed values of recovery of greater than 90% for Zn and 98% for Cu and Ni. The characterization of PCBs by SEM–EDS analyses showed that plates mainly consist of Cu, Ni, and Zn. PCBs can be seen as a potential secondary resource for the recovery of copper, nickel, and zinc. The best potential and pH conditions for the extraction of Cu, Zn, and Ni were also determined on the basis of thermodynamic diagrams.
View
... 283 Thailand produced discarded mobile phones at approximately 1756. 22 Additionally, the results found that the possible range of produced waste from the mobile phone is in a range of approximately 1700 to 2500 tons/year; that is significant information for considering and preparing proper management systems, such as collection centers, dismantling processes, and recycling facilities for mobile phone waste management in Thailand. Figure 3 shows that the value of waste generation per capita for mobile phones in Thailand (2012-2021) fluctuated from 0.027 to 0.038 kg/year/capita. ...
Estimating the Generation of Discarded Mobile Phones and Highlighting Areas for Recycling Precious Metals from Printed Circuit Boards in Thailand
Article
Full-text available
  • Dec 2022
Over the last decade, Thailand imported approximately 21 million units of new mobile phones every year, equivalent to 262 million. While technology changes, consumers want the newest model to serve their lifestyle. These discarded mobile phones will be a challenging issue for waste management systems because of the metals in mobile phones, especially in printed circuit boards (PCBs). Sufficient and sustainable management is needed to maximize the benefits of recycling metals and minimize potential risks to public health. This study aims to estimate the possible range of DMP generation in Thailand (2012–2021) with the Approximation 2, Simple Delay, and Time Step methods using the government published data and a literature review. The results show that the discarded mobile phones ranged from approximately 1700 to 2500 tons/year, equivalent to 0.027 to 0.038 kg/year/capita over the last ten years. In 2021, more than half of the total mobile phone waste generated in the northeastern and central areas of Thailand was around 468.73 and 325.14 tons/year, respectively. Additionally, 1.28 tons of precious metals (Ag, Au), 5.33 tons of rare earth elements, and 7.26 tons of toxic metals (As, Cd, Cr, Pb) can be found in the PCB waste of DMPs.
View
Towards electrochemical iridium recycling in acidic media: effect of the presence of organic molecules and chloride ions
Article
Full-text available
  • Mar 2023
The utilization of iridium is expected to surge in the next few years, notably due to the rising implementation of water electrolyzer devices in the energy transition. However, the natural resources of this noble metal are extremely limited and thus its recycling will become of high importance. Unfortunately, iridium is also the most corrosion resistant platinum group metal, making its recovery from waste a difficult and energy-demanding process. Hereby, we study the impact of organics and chloride ions on the electrochemical dissolution of iridium in order to pave the way towards green recycling of this precious metal. We present a 40 times increased dissolution when cycling iridium in presence of HCl and 1 M ethanol compared to HClO4. Our results point towards the direction of destabilizing Ir at relatively mild conditions in acidic media.
View
View
Applications of Supramolecular Materials in Real World: A Mini Review
Article
The breakthrough in supramolecular chemistry came in the 1960s when Charles J. Pedersen utilized the concept of ‘chemistry beyond molecules’ in the synthesis of the crown ethers. Self-assembly could allow for the construction of fascinating supramolecular architectures that are otherwise challenging to prepare using covalent chemistry. Supramolecular chemistry has been extensively studied in recent decades and its applications have been explored to include everything from molecular machines and sensors to gas absorption and nanoreactors to chemical catalysis and drug delivery. In this review article, some of the commercial applications are discussed to highlight the transition of supramolecular chemistry from theoretical concept to market.
View
One-step separation of tin from e-waste by a chemical vapor transport process (CVT): Preparation of nano-SnO2
Article
  • Jan 2023
E-waste is a valuable resource for the recovery of secondary metals. However, traditional methods only focused on the extraction of Cu and noble metals (Au, Ag, etc.), and significant tin (Sn) loss occurred during the smelting or the leached. In this paper, a novel chemical vapor transport (CVT) process was proposed to separate and recycle Sn from e-waste to prepare nano-SnO2. The effect of roasting parameters on Sn volatilization and characterization of nano-SnO2 were investigated using thermodynamic analysis, XRD, SEM, TEM, etc. The results indicated that Sn volatilization of 92.8 % was obtained under optimal roasting parameters under CO-CO2-N2 atmosphere. In addition, nano-SnO2 with a crystallinity of 99.9 %, an average grain size of 24.8 nm and a specific surface area of 97.9 m2/g was synthesized successfully.
View
Creating New Jewellery with precious metals recovered from electronic waste
Article
  • Dec 2022
It is estimated that electronic and electrical equipment discarded in 2021 weigh more than 57 million tonnes, and less than one-fifth of this electronic waste (e-waste) is recycled. The Printed Circuit Boards (PCBs) are the integral component of any electronic equipment, and this is a useful type of waste due to their nearly 30% metal content. This research aims to explore the hydrometallurgy technique to recover precious metals from e-waste, and to transform the materials into wearable jewellery through developing new ways of utilising this material, specifically working with metals in solution.
View
Complex Life Cycles of Precious and Special Metals
Chapter
Full-text available
  • Jan 2010
This chapter discusses the production, supply and recycling of precious and special metals. It explores the optimization of life cycles of these metals, highlighting their broad range of applications. First, it discusses the manufacture of minor metals, including the ways to optimize the yield of minor metals to improve resource efficiency and sustainability. It then turns to the role of effective recycling on metal/product life cycles. The societal, legislative, and structural factors that play a role in the life cycle of precious and special metals are also examined.
View
Mining our computers - opportunities and challenges to recover scarce and valuable materials
Conference Paper
Full-text available
  • Sep 2008
Waste Electronic and Electrical Equipment is unjustly regarded as mainly a waste management problem. Based on its content of base, special and precious metals, the large number of units, the resulting metal value and the growth rate of the annual sales (W)EEE represents an tremendous metal resource. This should be utilized through effective recycling, which has a much lower environmental footprint than primary production. The ac-tual amount of WEEE recycled today is embarrassingly low since insufficient EEE is collected and part of the collected EEE is exported to developing countries, where it is largely not entering official recycling systems. To achieve a global recycling society issues like technology, economics, life cycle structure, stakeholder awareness and legislation have to be addressed in a global, co-operative manner so that sustainable closed product cycles can be obtained.
View
View
India: Including the existing informal sector in a clean e-waste channel
Article
  • Jan 2008
Waste electrical and electronic equipment (WEEE) or e-waste is increasingly generated and processed in India. The waste originates from both national consumption (330'000 t) and waste imports (50'000 t). In India the e-waste processing and recycling is managed almost entirely (95%) by informal recycling businesses. Due to the application of inappropriate techniques, this sector bares high risks of environmental and occupational hazards and also looses valuable materials. Formal recycling industries have to compete with the informal businesses and simultaneously comply with environmental and occupational regulations. In Bangalore, the IT hub of India, the three newly-born formal recycling industries compete with scrap dealers for the big lots of e-waste from large companies, which result in material flowing into the uncontrolled informal sector. Promoting e-waste disposal policies in companies reduces the amount of e-waste flowing into the informal sector and creates incentives for formalization. The formalization of the informal sector into a transparent recycling system is crucial for a better control on environmental and human health impacts. In the same time, it bears the advantage to profit from their network, allowing for a better collection system, and preserves the employment generated in the poorest strata of the population. This paper demonstrates a case study of assistance for the authorisation process with an association of informal dismantlers. Alternate business models guiding the association towards authorisation have been developed, where a city wide collection system feeding the manual dismantling facility and an export strategy towards best available technology facilities to yield higher revenue from printed circuit boards are promoted. By replacing the traditional wet chemical leaching process for the recovery of gold with the export towards integrated smelters and refineries, safer practice and higher revenue per unit of e-waste collected are generated. Further assistance for establishing collection system and for complying with legal requirement will be necessary, as well as monitoring of the recycling processes to ensure their reputation after being authorised.
View
Exporting Harm: The High-Tech Trashing of Asia
Article
  • Mar 2002
Film Available: VHS format video with the same title: "Exporting Harm". For $50 donation. Please send check to the Basel Action Network (BAN).
View
Assessment of Precious Metal Flows During Preprocessing of Waste Electrical and Electronic Equipment
Article
The manufacturing of electronic and electrical equipment (EEE) is a major demand sector for precious and special metals with a strong growth potential. Both precious and special metals are contained in complex components with only small concentrations per unit. After the use-phase, waste electronic and electrical equipment (WEEE) is an important source of these “trace elements.” Their recycling requires appropriate processes in order to cope with the hazardous substances contained in WEEE and to recover efficiently the valuable materials. Although state-of-the-art preprocessing facilities are optimized for recovering mass-relevant materials such as iron and copper, trace elements are often lost. The objective of this article is to show how a substance flow analysis (SFA) on a process level can be used for a holistic approach, covering technical improvement at process scale, optimization of product life cycles, and contributing to knowledge on economy-wide material cycles. An SFA in a full-scale preprocessing facility shows that only 11.5 wt.% of the silver and 25.6 wt.% of the gold and of the palladium reach output fractions from which they may potentially be recovered. For copper this percentage is 60. Considering the environmental rucksack of precious metals, an improvement of the recycling chain would significantly contribute to the optimization of the product life cycle impact of EEE and to ensuring the long-term supply of precious metals.
View
A Review of the Environmental Fate and Effects of Hazardous Substances Released from Electrical and Electronic Equipment During Recycling: Examples from China and India
Article
With the increasing global legal and illegal trade of waste electrical and electronic equipment (WEEE) comes an equally increasing concern that poor WEEE recycling techniques, particularly in developing countries, are generating more and more environmental pollution that affects both ecosystems and the people living within or near the main recycling areas. This review presents data found in the scientific and grey literature about concentrations of lead (Pb), polybrominated diphenylethers (PBDEs), polychlorinated dioxins and furans as well as polybrominated dioxins and furans (PCDD/Fs and PBDD/Fs) monitored in various environmental compartments in China and India, two countries where informal WEEE recycling plays an important economic role. The data are compared with known concentration thresholds and other pollution level standards to provide an indication of the seriousness of the pollution levels in the study sites selected and further to indicate the potential negative impact of these pollutants on the ecosystems and humans affected. The review highlights very high levels of Pb, PBDEs, PCDD/Fs and PBDD/Fs in air, bottom ash, dust, soil, water and sediments in WEEE recycling areas of the two countries. The concentration levels found sometimes exceed the reference values for the sites under investigation and pollution observed in other industrial or urban areas by several orders of magnitude. These observations suggest a serious environmental and human health threat, which is backed up by other studies that have examined the impact of concentrations of these compounds in humans and other organisms. The risk to the population treating WEEE and to the surrounding environment increases with the lack of health and safety guidelines and improper recycling techniques such as dumping, dismantling, inappropriate shredding, burning and acid leaching. At a regional scale, the influence of pollutants generated by WEEE recycling sites is important due to the long-distance transport potential of some chemicals. Although the data presented are alarming, the situation could be improved relatively rapidly by the implementation of more benign recycling techniques and the development and enforcement of WEEE-related legislation at the national level, including prevention of unregulated WEEE exports from industrialised countries.
View
Poisoning the poor: Electronic waste in Ghana”. Amsterdam: Greenpeace International
  • J Kuper
  • M Hojsik
Transboundary shipment of waste electrical/electronic equipment/electronic scrap - optimization of material flows and control
  • K Sander
  • S Schilling
The digital dump - exporting re-use and abuse to Africa
  • Jan 2005
  • J Puckett
  • S Westervelt
  • R Gutierrez
  • Y Takamiya
  • J. Puckett