Chemical recycling of electronic waste for sustainable livelihoods and material consumption in India

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Chemistry


Currently, only 12% of precious metals from electronic waste (e-waste) is recycled, and in India, this figure is as low as 1.5%. India is the world's 5th largest e-waste generator, producing more than 2 million tonnes per year which is compounded by e-waste imports from other countries and leads to large waste dumps and informal scavenging. The jewellery sector accounts for 49% of the global use of precious metals which in India involves a large proportion of predominantly female rural artisans who are subject to exploitative middlemen and poor wages and conditions, despite maintaining their cultural heritage.

This programme develops new chemical methods for the recycling of e-waste in order to generate a new metal supply chain for rural artisanal jewellers in India and to create a formalised e-waste system. We are combining chemical and metallurgical research to design, develop, and exploit new chemical reagents and methods for the recycling of metals such as gold, copper, and the rare earth elements from e-waste. We are targeting these metals due to their prevalence in modern electronics (one tonne of mobile phones contains about 300 g of gold, compared with one tonne of gold ore that yields only 3-8 g), and their potential use in a new metal supply chain that connects chemical recyclers and the rural artisanal jewellery industry in India (gold and copper). These chemical methods can also be conducted on a local scale, are less damaging to the environment and can gain provenance from the Bureau of Indian Standards.
We aim to develop a deep understanding of the chemical principles that dictate the extent of metal separations and dissolution processes and use these principles to define and produce metal separations suitable for the complexity of e-waste. To do this we will exploit an array of complementary techniques to determine chemical structure, define extraction equilibria, and understand mode of action. The collaborations between chemists, metallurgical engineers, and industrialists will facilitate process discovery and implementation, with the development of a new and sustainable metal supply chain from e-waste potentially negating the informal e-waste recycling industry in India.

To complete the circularity of this research work, we will work with rural artisanal jewellers to determine their needs, deliver workshops to develop the techniques required to fabricate high-value jewellery from e-waste metals, and provide provenance for these materials through the creation of a chain of custody mark. Exhibition pieces will be generated and displayed in India and the UK to promote this work and highlight the advantages of this approach.

This programme of research brings together leading academic researchers from the Universities of Edinburgh and Dundee in the UK, and Indian Institute of Technology (BHU) Varanasi and the National Institute of Design, Ahmedabad in India.

Planned Impact

The principle impact of this work will be on the rural artisanal jewellery sector in India through the generation of a new metal supply chain from regulated e-waste recycling. This would diminish the informal e-waste recycling sector in India and provide environmental and societal benefits to the local community.

The rural artisanal jewellery sector will see commercial gains using metals, primarily copper and gold, derived from electronic waste. This economic impact would provide societal and cultural gains by providing a direct, online access to metals with clear provenance. Commercial impact will arise for the e-waste recycling industries through licensing and patents and increased environmental sustainability would be delivered through the implementation of new solvent extraction processes by these businesses. The development of new metal separation processes would be an important technology which industries could exploit to enhance their abilities and economic advantages in order to shift away from the informal dumping of e-waste in India to a formal recycling supply chain. The research proposed here will also be applicable to the exploitation and recovery across the finite and critical metal resource landscape, from primary (e.g. mines) and other secondary (e.g. tailings) resources and would limit the high global warming potential of mining especially. The collaborative nature of the proposed research will foster global economic performance through the combination and exploitation of the strengths of UK and Indian researchers and the ability of this newly assembled team to provide a holistic and multidisciplinary approach to this challenge. It is evident, as highlighted in the support letters and governmental literature, that there is a significant need for researchers who are trained in this area.

The UK and Indian governments are committed to policies that demand the development of new technologies to facilitate a sustainable lifestyle, including the decarbonisation of energy supply in order to reduce carbon dioxide emissions to 50% of 1990 levels by 2027 and the recycling of waste products, in particular those which have critical and precious metal resource. The proposed research will result in cost-effective routes to metal recovery from a valuable and plentiful waste product. The new programme will further support and strengthen the economic and environmental policies set out by these governments and would act as an exemplar for clear policy direction in the future. It will also promote rural cultural identity through artisanal jewellery manufacture and provide economic stability to the primarily female jewellery makers.

HEIs, school students, and the wider public will be beneficiaries by learning about the world's finite resources, their uses in today's leading technologies, their production and recycling, and the exploitation of the chemical sciences in a sustainable lifestyle. Science demonstrations in these areas, focussing on the chemistry involved in metal recovery and their significance to science and the economy will demonstrate the contribution that the chemical sciences can make to society, the quality of life, and the economy.

The collaborative interactions in this programme will provide teaching, research, and transferable skills development for PDRAs and students who will meet permanent staff and visitors working at the cutting edge of their disciplines. They will present their work in a variety of formats to leading researchers and process engineers at meetings and conferences and will develop transferable skills from our in-house training programmes and those associated with this scientific project that runs across different laboratories and countries.
Description We have developed new, low-carbon technologies for recycling copper, gold, and other metals from waste printed circuit boards (WPCBs) and Central Processing Units (CPUs)s from end-of-life electronic equipment. This involves manually separating the WPCBs and removal of the components (CPU) and delaminating and downsizing the WPCBs.

We have investigated methods for the dissolution of metals from these components, and have developed two-stage leaching processes which results in a bulk separation of base (e.g., copper) from precious (e.g., gold) metals. This provided two feed streams for copper and gold purification using solvent extraction methods and resulted in pure, and completely recycled, copper and gold solutions. Alternatively, we have discovered a new dissolution method which makes uses organic solvents, hydrogen peroxide, and a chloride source such as oxalyl chloride to dissolve the noble metals. This process is extremely rapid (minutes) and facilitates the straightforward separation of metals such as gold and copper from e-waste using biphasic separation techniques.

We have also developed new low-carbon metal separation processes that make use of supramolecular chemical interactions to control selectivity. We have discovered a new diamide reagent that acts as a selective precipitant of gold directly from aqueous acidic leach solutions. This negates the use of organic solvents in separation processes and so improves the sustainability of the process. By modifying the acid strength, we can also target other metals for precipitation, such as iron, gallium, tin, and platinum. This process has been patented by the University of Edinburgh. We have also developed a new pyrazinecarboxylic acid reagent for the precipitation of copper directly from similar leach solutions. As such, using a combination of these precipitants allows us to target the two most valuable metals for recycling from e-waste.

We have initiated life-cycle analyses (LCA) of our processes to gain a better understanding of their economic and environmental sustainability in order to position them against the state of the art.

We have carried out a comprehensive survey of artisanal jewellers across India and in particular in Varanasi, on their use of gold and other metals in their art and the social acceptance of using metals directly from e-waste. We have held a conference in India that combined demonstrations by artisanal jewellers in workshops with chemistry/engineering scientific sessions to bring together scientists and artists. We have also develop new approaches to gold and copper metal work in Dundee using gold solution chemistry, electroforming techniques, and Koftgari gold pressing. These approaches will lead to the development of display pieces for museums in India and Scotland.
Exploitation Route We have managed to deliver some excellent advances in this area, but there remains a need to ensure that technical feasibility moves towards commercial feasibility. We are currently engaging with industrial partners to progress the primary aspects of the metal separations work into the commercial arena. Furthermore, the final conceptual proof for developing a new supply chain for use by artisanal jewellers remains in its infancy. In theory, the new recycling processes should be able to deliver both gold and copper streams to the metalsmiths and it remains a key objective to produce display items for both Indian and Scottish museums directly from e-waste.

We have also shown how it is possible to exploit fundamental chemical understanding to deliver new solutions in metal separation technology. The supramolecular chemistry associated with these advances could be exploited by others in the field.
Sectors Chemicals,Electronics,Manufacturing, including Industrial Biotechology,Culture, Heritage, Museums and Collections

Description BHU Varanasi 
Organisation Indian Institute of Technology BHU
Country India 
Sector Academic/University 
PI Contribution A new engagement with Prof. Kamalesh Singh at IIT BHU was established through the award of a UKIERI grant which allowed exchange visits to take place. This subsequently led to the EPSRC-GCRF award linked to this report.
Collaborator Contribution A new engagement with Prof. Kamalesh Singh at IIT BHU was established through the award of a UKIERI grant which allowed exchange visits to take place. This subsequently led to the EPSRC-GCRF award linked to this report.
Impact Still on-going. Outputs and outcomes have been hindered due to COVID-19 pandemic and a temporary 6 month halt on the funding.
Start Year 2018
Description University of Dundee 
Organisation University of Dundee
Department Duncan of Jordanstone College of Art and Design
Country United Kingdom 
Sector Academic/University 
PI Contribution Prof. Sandra Wilson has spent time in my laboratories learning how to recycle copper and gold from electronic waste using chemical methods, followed by its use in jewellery design.
Collaborator Contribution Prof. Sandra Wilson has facilitated the development of links with jewellers and designers in India to provide a clear economic and societal objective to the recycling of electronic waste in India, such that a new metal material stream can be developed for Indian artisan jewellery makers.
Impact not yet applicable
Start Year 2017
Title Method of selective precipitation of metals using amide compounds 
Description The present invention relates to compounds and methods for separating metals. In particular, but not exclusively, the invention relates to compounds and methods for separating and/or precipitating metals, and in particular, gold, from a solution. 
IP Reference  
Protection Patent / Patent application
Year Protection Granted 2022
Licensed No
Impact none yet arising