Editor's note: This article originally ran on e-tech and appears here courtesy of the IEC.
The circular economy is the model for cities of the future. The transition towards smart and sustainable cities requires moving from a linear model of “extract, manufacture and discard” to a circular economy where materials are continuously recovered and reused, in a new world order known as “urban mining”.
As cities become denser and more technologically integrated, electronic and electrical waste (e-waste) represents both an environmental challenge and one of the largest untapped economic opportunities in urban infrastructure.
Informal channels for e-waste processing are still the norm
E-waste recycling today is still a wild west of small or individually run operations in most developing countries, where dumped electronics are stripped for valuable elements. Smart cities expert Ripin Kalra says that there is a whole spectrum of informal urban mining, with these informal processes still taking the lion’s share of materials recovery around the world. "Informal urban mining is happening in developing countries and even in the developed world. I grew up in India and I remember that nothing ever went to waste. Even the smallest bits of plastic and paper were collected from home. You were paid some money by the collectors for these bits and pieces and they would go and recycle them. These small mum and dad shops played extensive informal urban mining roles and remain a thriving business in many parts of the world."
While this informal economy is important for the livelihoods of many people, polluting e-waste dumps have a deleterious impact on the health of communities living and working nearby - in addition to having a terrible effect on the environment, with toxic materials contaminating both the earth and water. “These informal practices are not the healthiest, most secure way of doing things. It’s urban mining with the worst health and safety concerns possible,” Kalra admits.
He also acknowledges that a shift towards more formal urban mining processes is required, as valuable materials - notably used for the energy transition in the fight to meet net zero targets - need to be recovered and this is becoming a strategic concern in most countries around the world. "There are two or three things that are happening in parallel. Increasing regulation is focusing on extractive mining, for environmental reasons. There's a lot of scrutiny around mining because the industry is under the spotlight for not using clean processes and increasing pollution. On the other hand, getting the materials you want like lithium or cobalt, particularly to make batteries, is important; cities are increasingly reliant on lithium-ion batteries and other electronics like chipsets. Therefore, if you imagine the city of the future, which wants to achieve its ambitions around renewable energy, while being digital and data centric, it needs to guarantee a continuous supply of these critical materials. That’s where more formal urban mining processes come in and in addition to supplying critical materials, they can be a formidable tool to reduce e-waste using efficient and sustainable processes," he explains.
Formal processes are gradually implemented
Many examples of formal processes for urban mining are or have been effective around the world. Japan used modern urban mining frameworks leading up to the Tokyo Olympics with a nationwide campaign. According to this article in JapanUp!, the country’s citizens collected 6,21 million used mobile phones and 79 000 tonnes of small electronics. Urban miners extracted 32 kg of gold, 3 500 kg of silver and 2 200 kg of bronze and copper, manufacturing 100% of the 5 000 Olympic and Paralympic medals directly from e-waste.
In Belgium, Antwerp hosts one of the world's most advanced urban mining industrial complexes. The company claims to process several hundred thousand tonnes of materials to extract more than 20 different metals, including gold, silver, platinum, palladium, indium and tellurium with recovery efficiencies exceeding 95%. While India has a wide informal urban mining network, it is also implementing more formal ways of recovering e-waste. Named the Indian Silicon Valley, Bengaluru ranks third among Indian cities in e-waste generation, contributing an estimated 10% of the country's total, according to figures reported from the Karnataka Pollution Control Board.
This article states that IT companies alone are estimated to generate around a thousand tonnes of e-waste every month in the city. While most of the recycling is still informal, moves are being made to transition from using polluting dismantling yards to more structured eco-industrial parks. Bengaluru now houses over 28 authorized facilities driving formal reverse logistics, recovering copper and precious metals for domestic electronics manufacturing, like this company.
But while formal processes around the world exist, they most often need to be vastly improved, according to IEC Systems Committee for Smart Cities (SyC Smart Cities) expert N. Kishor Narang: “currently the collection is quite fragmented, as it requires complex reverse logistics, multi-stage sorting, hazardous material handling and chemical extraction. E-waste urban mining is technically advanced at the refining stage but operationally underdeveloped in municipal collection systems. Up to 78% of global e-waste still bypasses formal recycling channels due to product miniaturization, hazardous components and poor consumer return infrastructure.”
The multiple reasons for urban mining
E-waste metals include precious metals such as gold, silver, palladium and platinum; base infrastructure metals such as copper, aluminium, iron, nickel and tin; and critical and rare earth elements including neodymium, dysprosium (permanent magnets in EV motors and wind turbines), indium (touchscreens), lithium and cobalt (batteries).
E-waste is significantly richer in precious and critical metals than natural geological deposits. One metric tonne of smartphone circuit boards contains 150 to 300 grams of gold, according to this article. By comparison, high-grade natural gold ore typically yields only 1 to 5 grams of gold per tonne. This research claims that printed circuit boards (PCBs) contain between 10% and 20% copper by weight, compared to less than 1% copper content in most virgin copper ores. The mere value of these metals and minerals is one of the important economic justifications for urban mining.
Ensuring supply chain security in addition to providing critical raw materials is also key. Smart cities rely heavily on IoT sensors, 5G/6G networks, electric vehicles (EVs) and smart grid power electronics. These technologies require copper, lithium, cobalt and rare earth elements. Virgin mining of these materials is fraught with geopolitical risks and ecological destruction. Urban mining creates a localized, sovereign supply of strategic metals, without relying on imports. China is the biggest exporter of lithium-ion batteries, for example, making importing countries strategically vulnerable and dependent, as they seek to achieve their energy transition.
Another important reason results from environmental and public health protection concerns. E-waste represents only around 3-5% of municipal solid waste by weight, but it accounts for up to 70% of toxic heavy metals (lead, mercury, cadmium, beryllium) entering municipal landfills. Urban mining prevents toxic leachate from contaminating urban soil and groundwater aquifers.
In addition, extracting metals from e-waste uses significantly less energy than primary ore extraction, thereby reducing global emissions: recycled copper requires around 85% less energy than mining virgin ore, for instance. Spatial optimization is yet another driver. Modern cities cannot afford endless landfill expansion. Diverting high-density waste into closed-loop processing plants frees up valuable suburban land.
What are the tech challenges and advances ?
Unlocking the full potential of urban mining requires overcoming the challenge of product complexity. Electronics are tightly glued, complex composites of plastics, ceramics and alloys. Four key technological breakthroughs are solving this problem, says Narang. He points to AI-powered robotic sorting and hyperspectral imaging. Facilities deploy computer vision, deep learning and X-ray fluorescence (XRF) sensors mounted on robotic arms.
“AI models analyze shredded or whole electronics on high-speed conveyor belts, identifying board types, capacitor compositions, and specific alloy grades in milliseconds, sorting them with over 98% accuracy,” he explains. He also points to modern bioleaching techniques (microbial extraction).“Traditional metal extraction relies on energy-intensive smelting (pyrometallurgy) or harsh toxic acids (hydrometallurgy). Bioleaching uses naturally occurring or bio-engineered microorganisms such as acid bacillus bacteria or cyanogenic fungi to extract metals.”
He adds, “bacteria producing organic acids selectively dissolve copper, gold and rare earth elements from printed circuit boards at room temperature, which cuts operational energy costs by around 40%, eliminates toxic chemical runoffs and yields up to a 95% metal recovery rate with minimal carbon emissions.”
Direct recycling and solvometallurgy is another technology that can help the urban mining quest, notes Narang. Instead of breaking down materials to pure elements, advanced solvometallurgy uses green organic solvents to dissolve specific battery binders or plastics without destroying the underlying cathode crystals. This allows for the direct recovery of battery-grade lithium-nickel-manganese-cobalt (NMC) precursors, saving massive amounts of processing energy.
Finally, digital product passports (DPP) and blockchain tracking are an important step forward as “one of the largest hurdles in urban mining is not knowing what materials are inside a device,” notes Narang. “Under emerging regulations such as the EU Digital Product Passport framework, products receive digital twins storing exact component maps, chemical makeup and disassembly guides. Disassembly robots scan the passport to instantly know how to harvest intact components.”
What standards exist?
The IEC has recently set up a new joint committee with ISO - ISO/IEC JTC 5 - to develop digital product passport standards. Its work will focus on the development of deliverables for the deployment of DPPs, ensuring cross-sectoral and cross-system interoperability to enable the supply chain information flow.
(For more on this new committee, read its Chair’s interview here.)
The BS ISO 59000 series deals with some of the aspects of urban mining and ISO is working a new standard, ISO/DIS 14002-4, which addresses environmental aspects and associated impacts across the lifecycle including the extraction, processing, use, recovery and end-of-life treatment of material resources. IEC 62430 enables environmental aspects to be considered at every stage of product development, enabling manufacturers to make their devices more durable, repairable, reusable and recyclable while maintaining their intended functionality and performance. IEC 63395 is another standard developed by the IEC Technical Committee responsible for environmental standardization, IEC TC 111. The IEC Standard helps to deal with the systematic and sustainable management of e-waste, based on the concept of extended producer responsibility. It addresses all e-waste management steps, from collecting to returning recovered products, components, materials or energy to the value chain.
But more standards, specifically in the smart city space, would be required as well. Kalra thinks more should have been done to provide benchmarks for smart cities on this topic earlier on, notably in the SyC Smart Cities. "It should have been done yesterday so the sooner this is addressed, the better. Resources, technical advice, all those things need to flow and converge to help cities gain ground on this matter. There has to be some clear guidance, if not standardization, on how to set things up correctly, efficiently, sustainably and safely,” he says.
Maybe some of the solutions lies in the future work of this new smart cities joint committee between IEC and ISO. Its remit spans resilience and disaster risk reduction, sustainability and sustainable mobility and transport as well as community infrastructure. So watch this space!
