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UNSW SMaRT Centre researchers have had published a study into the latest research of metal recycling from e-waste, which shows the environmental, economic and social (circular economy) benefits that could be derived from using up-to-date recycling technologies.
Published in The Royal Society's "Sustainable metals: science and systems" Journal, the study , carried out under and funded by SMaRT's ARC Industry Laureate Fellowship for Green Metals, discusses the urgency of metal recycling from e-waste for sustainability and economic benefit, up-to-date recycling technologies with an emphasis on their potential role in creating a circular economy in e-waste management.
Key findings:
- The rapid increase in worldwide e-waste generation is a direct consequence of the expansive growth in the electronics industry and the swift transition in the market trends for electronic devices.
- Unfortunately, inadequate management practices, notably landfilling and incineration, exacerbate environmental contamination by releasing toxic chemicals and heavy metals into ecosystems.
- Recognising this issue, researchers have diligently explored metallurgical and thermochemical processes to establish a comprehensive value chain, incorporating the recovery of both metallic and non-metallic compounds from e-waste.
- Several investigations have demonstrated the viability of reclaiming metal compounds utilizing metallurgical methods like hydrometallurgy, biometallurgy, pyrometallurgy, combined metallurgy, and a few other emerging technologies, such as supercritical fluid extractions, cryomilling and microrecycling techniques, etc.
- Considering the consistent rise in the yearly market value of metals, approaches for recovering metals and their alloys from e-waste arise as potentially efficient strategies capable of yielding profits and curbing environmental pollution.
- Consequently, the findings along with emerging technologies, such as implementing a small-scale recycling strategy, smart collection of e-waste, green design strategy, etc., propose an efficient pathway to establish circular economic platforms for electrical and electronics devices - such as SMaRT's very own various MICROfactorieTM Technologies that reform hard to recycle wastes into new products and feedstock for remanufactoring.
- Despite the promising outlook, the practical implementation of these technologies encounters several technical challenges that require careful consideration and resolution for successful integration into waste management systems. Contemporary metallurgical practices and studies that are aimed at reducing energy and chemical consumption should be explored, thereby enhancing overall efficiency, effectiveness and practical applicability.
- Incorporating the advanced LCA studies that will include the advancements in metallurgy and thermochemical processes is needed. By addressing these key issues, future research endeavours can contribute significantly to the development and implementation of sustainable practices in managing and recycling e-waste for valuable metals to ensure the circular economy of valuable metals.
Background
The global demand for consumer electronics like handheld devices, laptops, computers and kitchen appliances, and the widespread adoption of electric vehicles has led to the exponential increase in the generation of electrical and electronics waste (e-waste). The annual e-waste generation reached more than 62 million tonnes per year in 2022, making it the fastest growing waste stream globally. This massive volume, containing potentially hazardous materials like heavy metals and organic chemicals, poses significant environmental threats. Consequently, the implementation of efficient and effective e-waste management strategies is imperative to mitigate these detrimental environmental impacts.
However, a substantial portion of e-waste is still managed through traditional methods such as landfilling and incineration in developing countries, while developed countries are transporting their waste to less privileged countries (sometimes illegally) prioritizing volume reduction. These practices, while simple in implementation, incur significant environmental consequences, including the emission of harmful gas into the atmosphere, the generation of contaminated wastewater and soil pollution. Moreover, the retrofitting of existing treatment facilities with additional pollution control equipment exacerbates waste management costs, potentially hindering the financial viability and widespread accessibility of these approaches.
Despite containing valuable inorganic components, including rare earth elements (REEs) such as lanthanum (La), neodymium (Nd) and dysprosium (Dy), precious metals like platinum (Pt), gold (Au) and silver (Ag), and other valuable metals like lithium (Li), nickel (Ni) and titanium (Ti), only 22.3% of these metals are possibly recovered as per the recycling rate of 2022. This results in an annual loss of approximately USD 62 billion worth of metals through landfilling, incineration and other improper methods. To address this challenge, researchers are increasingly focusing on the development of circular economy platforms for e-waste, primarily through technical enhancements. Notably, various metallurgical processes, such as hydrometallurgy, biometallurgy, pyrometallurgy and hybrid approaches, are being explored to achieve more efficient metal recovery from e-waste. As metals constitute critical resources for diverse industries, their sustainable extraction from e-waste offers economic benefits by directly reducing supply costs within these sectors.
Therefore, this review was prepared to provide a comprehensive overview of recovering the valuable metals and alloys from e-waste. Recycling of metals from the e-waste that is embedded with valuable metallic compounds, such as printed circuit boards (PCBs), small consumer electronics, hard drives and batteries, are considered in this work. The sources and the value of the embedded resources, their recycling technological intervention and circular economy of the materials for these e-waste metals, are discussed.