Millions of unused smartphones in Norway are creating a hidden stock of materials, but accessing their rare-earth elements will require improved collection, targeted separation, and recycling-focused product design.
Paper: Hidden Mine: The Quantity of Critical Raw Materials in Hibernating Smartphones, a case study of Norway. Image Credit: Vejitum / Shutterstock
As the global transition to clean energy and advanced digital infrastructure accelerates, the demand for critical raw materials continues to grow. A recent study posted on the SSRN preprint server investigated the quantity of these materials held in dormant smartphones in Norway and their potential as a secondary resource. The findings remain preliminary because the paper has not undergone peer review.
By employing dynamic material flow analysis alongside elemental characterization of individual device components, researchers examined the quantity and composition of materials stored in selected components of both active and dormant smartphones. The findings showed that dormant smartphones now outnumber those in active use, with millions of stored devices containing material stocks dominated by silicon and copper, alongside much smaller quantities of strategically valuable rare-earth elements such as neodymium. Improving collection systems and targeted recovery techniques could improve access to these resources, thereby strengthening circular material supply chains.
The Urgent Need for Strategic Mineral Recovery
The rapid deployment of renewable energy technologies and smart electronic systems has intensified the demand for critical raw materials (CRMs). Rare-earth elements (REEs), including neodymium, praseodymium, dysprosium, and yttrium, possess unique properties that make them essential for high-performance applications. However, primary mining and ore processing impose significant environmental burdens and face geopolitical supply risks.
To mitigate these challenges, European policy initiatives, such as the European Union's Critical Raw Materials Act, promote circular economy practices and secondary resource recovery. Despite these initiatives, current electronic waste management systems recover rare-earth elements at low concentrations inefficiently, resulting in the loss of valuable materials during conventional shredding and smelting processes. These limitations highlight the need to re-evaluate urban mining.
Methodology: Mapping Material Stocks in Smartphones
To quantify the CRMs in consumer smartphones, researchers combined dynamic material flow analysis with elemental analysis. They traced smartphone inflows, active use, household hibernation, and waste outflows in Norway from 2007 to 2024, leveraging trade data from Statistics Norway, a national survey of 300 respondents, and Weibull lifetime distributions derived from the survey data to estimate how long devices remained in use or storage.
For the elemental analysis, 15 smartphones manufactured between 2008 and 2015, representing up to 12 models, were disassembled to collect vibration units, displays, and microphones. Following chemical digestion, the components were analyzed using inductively coupled plasma mass spectrometry to quantify 67 elements, including 44 CRMs and 16 REEs. Because the researchers examined only three components from a small sample of older phones, they described the totals as a possible lower boundary for whole-device CRM and REE content.
The analysis showed distinct material distributions across components. Microphones contained the highest proportion of critical materials among the analyzed components, at 42% by mass, with 37% copper and 2% nickel. Vibration units were enriched with permanent magnet elements, averaging 5,200 mg/kg of neodymium, alongside praseodymium, gadolinium, and dysprosium. Display modules contained about 28% critical materials, primarily comprising 21% silicon and smaller amounts of yttrium.
Assessing the Scale of Dormant Urban Mines
The study indicated that unused smartphones represent a potentially significant secondary stock of CRMs. In Norway, smartphones were estimated to remain in active use for an average of 4 years before spending an additional 6 years in household storage, resulting in a total modeled lifetime of 10 years. Consequently, the dormant smartphone stock has grown steadily, exceeding 10 million units by 2024, compared with an active stock of 6.8 million units. The model did not explicitly account for second-hand use or cross-border device movements and applied constant lifetime distributions across the study period.
Across the components analyzed, active and dormant smartphones in Norway were estimated to contain about 80 tonnes of CRMs. In 2024 alone, the annual flow from dormant devices into the end-of-life waste stream reached more than seven tonnes of critical raw materials and approximately 15 kilograms of rare-earth elements. Notably, neodymium accounted for 76% of the rare-earth content by mass across the three analyzed components, followed by praseodymium at 9%, yttrium at 5%, and gadolinium at 4%.
Enhancing Resource Recovery in the Circular Economy
Component-level disassembly could facilitate the recovery of neodymium-iron-boron permanent magnets from vibration units, thereby reducing the risk of valuable magnetic alloys being lost during conventional waste processing. Display modules contained silicon, which constitutes about 21% of display mass, but the study did not assess whether it could be recovered economically.
The analyzed internal microphones contained 37% copper and elevated levels of precious metals, although the study did not assess their recovery or compare their energy requirements with primary production. Additionally, reuse, repair, refurbishment, and remanufacturing could help preserve critical materials embedded in specific components and keep them in circulation for longer.
Pathways to Improve Critical Resource Recovery
In summary, this study highlights a significant gap between circular economy goals and current recycling infrastructure. While conventional mechanical shredding and pyrometallurgical smelting can recover selected base and precious metals, they can also result in the loss and dissipation of low-concentration rare-earth alloys. Given that REEs account for less than 0.2% of the total critical raw material mass in smartphones, existing recycling systems tend to prioritize high-volume base metal recovery over recovering low-concentration REEs.
Addressing this limitation would require moving from mixed-device recycling to component-level sorting and dismantling, potentially supported by automation to reduce the labor and cost associated with manual disassembly. Integrating design-for-recycling measures, such as standardized magnet assemblies and easily detachable components, could improve the economic viability of specialized recycling. Furthermore, combining Digital Product Passports with design-for-recycling, component-level separation, scalable recovery technologies, and specialized recycling streams could support more targeted material recovery. However, the authors cautioned that product information alone is insufficient to overcome current technical and economic barriers.
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