Electronic waste (e-waste) refers to discarded electronic devices such as smartphones, laptops, televisions, and other consumer or industrial electronics that are no longer functional or needed. These devices contain materials that can be harmful to the environment, but recycling them helps reduce pollution and conserve resources.
This article discusses the key materials extracted from e-waste, the processes used to recover them, and the technologies making e-waste recycling more efficient and eco-friendly.
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Key Materials and How They Are Extracted
Gold and Silver
Recovering gold and silver from e-waste typically involves chemical leaching, where metals are dissolved from circuit boards. Strong acids or cyanide-based solutions are traditionally used, but these pose serious environmental and health risks.
Researchers have explored thiourea as a more sustainable alternative, which offers faster reaction rates and lower toxicity. However, its high consumption and rapid decomposition limit its effectiveness. To overcome these challenges, bioleaching is being investigated as a greener solution. This process uses microorganisms to oxidize metal compounds, enhancing dissolution and achieving recovery rates of up to 90 %.1
Once extracted, gold and silver are purified and repurposed across various industries. Their excellent conductivity and corrosion resistance make them essential in electronics manufacturing. Additionally, they are widely used in jewelry, aerospace components, and medical devices.
Copper
Copper is widely used in electronics and can be efficiently recovered from e-waste. Printed circuit boards (PCBs) alone contain around 322,000 tons of copper globally, making them a significant source for recycling.
The process begins with mechanical shredding, which breaks down electronic components and separates copper-rich materials. These fragments are then purified through electrolysis, where an electric current removes impurities, yielding high-quality copper for reuse.
Recycled copper is essential for manufacturing electrical wiring, motors, and new electronic devices. Recovering it from e-waste helps reduce the demand for newly mined copper and minimizes environmental impact.
Researchers are using AI to improve copper recovery from e-waste. A recent study explored data-driven methods to optimize the leaching process, focusing on key factors such as acid concentration, oxidants, and reaction time.
To enhance efficiency, the researchers developed predictive models using the Adaptive Neuro-Fuzzy Inference System (ANFIS) and Response Surface Methodology (RSM). ANFIS delivered more accurate results, with an error rate of about 6.03 %, outperforming RSM. The study also introduced 3D interactive plots to identify optimal process conditions, improving automation potential.
These findings highlight how AI can refine metal recovery, making e-waste recycling more precise, cost-effective, and environmentally sustainable.2
Rare Earth Elements
Rare earth elements (REEs), such as neodymium, dysprosium, and yttrium, are used in technologies like electric vehicles, wind turbines, and high-performance magnets. However, extracting them from e-waste is challenging because they are dispersed in small quantities.
Traditional recovery methods, such as thermal processing, can isolate REEs but require high energy and generate hazardous byproducts. Hydrometallurgical techniques, which use aqueous solutions to selectively dissolve and recover REEs, offer a lower environmental impact. Researchers are also developing greener solvent technologies to improve efficiency while reducing toxic waste.
One promising approach is ionic liquid (IL) extraction, an eco-friendly alternative to conventional solvent-based methods. Task-specific ILs are designed to enhance extraction efficiency, selectivity, and recyclability. Researchers are also testing different IL compositions, such as bifunctional and non-fluorinated variants, to improve REE separation from other materials.3
Lithium and Cobalt
Lithium-ion batteries, used in smartphones, laptops, and electric vehicles, contain valuable metals like lithium and cobalt. With the global lithium-ion battery market projected to reach $95 billion by 2025, the amount of spent battery waste could exceed 11 million metric tons by 2030.
Recovering these metals is crucial to reducing reliance on newly mined resources. Mining lithium and cobalt requires extensive energy and water use, leading to environmental degradation. Additionally, in some regions, cobalt extraction has been linked to unsafe working conditions, child labor, and human rights violations. Recycling these materials helps mitigate these ethical and environmental challenges.
Traditional recovery methods involve shredding batteries and using hydrometallurgical treatments, where acidic solutions dissolve lithium and cobalt for purification. However, these processes can be energy-intensive and generate harmful waste.
As an alternative, the researchers also examined emerging green approaches such as bioleaching and waste-for-waste (W4W) recycling, which utilizes organic waste-derived acids as eco-friendly leaching agents.4
Plastics and Metals
Extracting plastics and metals from e-waste involves several techniques. Mechanical separation is a common first step, sorting materials based on physical properties such as density, conductivity, and magnetism. Ferrous metals are separated using magnetic fields, while non-ferrous metals are sorted by density during shredding and screening. This process prepares materials for further refinement.5
For plastics, pyrolysis offers an alternative recycling method. This thermal decomposition process breaks plastics down into smaller hydrocarbon molecules in the absence of oxygen. The resulting compounds can be refined into synthetic fuels or raw materials for new plastic production. In addition to reducing plastic waste, this method generates energy, supporting a circular economy.6
Recovered plastics are repurposed for electronic casings, construction materials, and 3D printing filaments. Metals like aluminum and steel are reused in manufacturing, automotive, and construction industries, reducing the need for virgin resources and lowering carbon emissions.
How to Turn Electronic Waste Into Raw Materials | Change The Future
The Rise of E-Waste Recycling
Many companies are integrating sustainable practices and advanced recycling technologies to manage e-waste.
Sims Lifecycle Services (SLS) is a major player in IT asset disposition, offering environmentally responsible recycling for a wide range of electronic devices. Umicore, a global materials technology company, specializes in recovering precious metals such as gold, silver, palladium, and platinum from e-waste.
Large tech companies are also investing in automated recycling. Apple, for example, uses robots to extract valuable materials from discarded devices. Its Daisy robot can disassemble 200 iPhones per hour, recovering key components, including rare earth metals.7-9
As the volume of e-waste rises, developing efficient recycling methods is more critical than ever. Advances in bioleaching, robotics, AI-driven optimization, and green solvents are reshaping the industry. Machine learning and artificial intelligence, already used in predictive models for copper recovery, are improving the precision and automation of recycling processes.
Collaboration among governments, corporations, and researchers will be essential for scaling these innovations and ensuring long-term resource conservation. By embracing emerging technologies and sustainable practices, the industry can make e-waste recycling more efficient, cost-effective, and environmentally responsible.
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References and Further Reading
- Ray, D. A., Baniasadi, M., Graves, J. E., Greenwood, A., Farnaud, S. (2022). Thiourea leaching: an update on a sustainable approach for gold recovery from E-waste. Journal of Sustainable Metallurgy. https://doi.org/10.1007/s40831-022-00499-8
- Srivastava, S. K., Dhaker, K. L. (2024). Data-driven approach for Cu recovery from hazardous e-waste. Process Safety and Environmental Protection. https://doi.org/10.1016/j.psep.2024.01.013
- Kaim, V., Rintala, J., He, C. (2023). Selective recovery of rare earth elements from e-waste via ionic liquid extraction: A review. Separation and Purification Technology. https://doi.org/10.1016/j.seppur.2022.122699
- Roy, J. J., Rarotra, S., Krikstolaityte, V., Zhuoran, K. W., Cindy, Y. D. I., Tan, X. Y., ... & Srinivasan, M. (2022). Green recycling methods to treat lithium‐ion batteries E‐waste: a circular approach to sustainability. Advanced Materials. https://doi.org/10.1002/adma.202103346
- Chakraborty, S. C., Zaman, M. W. U., Hoque, M., Qamruzzaman, M., Zaman, J. U., Hossain, D., ... & Ahmed, M. B. (2022). Metals extraction processes from e-waste: constraints and opportunities. Environmental Science and Pollution Research. https://doi.org/10.1007/s11356-022-19322-8
- Andooz, A., Eqbalpour, M., Kowsari, E., Ramakrishna, S., Cheshmeh, Z. A. (2022). A comprehensive review on pyrolysis of E-waste and its sustainability. Journal of Cleaner Production. https://doi.org/10.1016/j.jclepro.2021.130191
- Sims Lifecycle Services. E-Waste and IT Recycling for Businesses. [Online] Sims Lifecycle Services. Available at: https://www.simslifecycle.com/business/e-waste-recycling/ (Accessed on January 1st, 2025)
- Umicore. Materials for a better life. [Online] Umicore. Available at: https://www.umicore.com/en/ (Accessed on January 1st, 2025)
- Reuters (2020). Apple pushes recycling of iPhone with 'Daisy' robot. [Online] Reuters. Available at: https://www.reuters.com/article/technology/apple-pushes-recycling-of-iphone-with-daisy-robot-idUSKBN1Z925O/ (Accessed on January 1st, 2025)
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