Writer: Ecrin Tekeş
As we delve into the world of recycling technologies, it’s clear that their impact on sustainability is more crucial than ever. The ban on composite landfills in Germany has propelled recycling to the forefront of environmental consciousness, emphasizing the need for innovative solutions. From reshaping the fate of composite waste to revolutionizing the recycling of used lead paste, the marriage of recycling and technology offers a beacon of hope. Let’s explore the transformative journey of these technologies and unravel the essence of their innovative solutions.
Recycling technologies have experienced significant development in recent years as sociotechnical pressures in waste management have increased. The ban on composite landfills in Germany has increased the impact of recycling technologies on sustainability. This contribution comprehensively reviews available recycling technologies for fiber-reinforced composites with low and high Technology Readiness Levels (TRL). In the development of sustainable recycling technology, determining the most suitable recycling methods for different types of fiber-reinforced composites is an important goal (Krauklis, A. E., 2021)
Composite waste refers to packaging that is formed by combining various materials. These materials are combined at the macro level into a single material, thus combining the appropriate properties of different materials or creating new properties. Composite wastes are materials formed by combining different materials such as paper, plastic, metal, glass, and wood. These wastes can extend the shelf life of products due to the materials they contain such as aluminum, plastic, and paper. This leads to their widespread use, especially in the packaging sector and industrial use. However, the fact that composite wastes are harmful to nature makes it imperative that they are recycled properly. In the process of recycling composite wastes, it should be emphasized that these wastes should be separated from other household wastes. The wastes are separated into pieces with the help of grinding machines and delivered to the recycling plant. After the shredding process, the wastes are separated depending on the amount of material they contain. This separation process includes materials sent to the kneader to be recycled as paper. After the recycling process is completed, the remaining aluminum is melted and turned into ingots. Composite wastes, which constitute half of the wastes produced in our country, cannot be thrown away due to their nature-damaging properties. Therefore, it is of utmost importance that they are properly recycled and included in the recycling process. The ban on composite landfills in Germany has increased the impact of recycling technologies on sustainability, as it has encouraged more conscious management of composite waste (Saydaş Plastik., 2021).
Another innovative solution we will consider is the recycling of used lead paste. Recycling of spent lead paste can be accomplished through various methods, such as pyrometallurgical and electro-recovery. Pyrometallurgy is a traditionally used method, but there are environmental pollution concerns. In recent years, more environmentally friendly technologies such as electro-recovery and hydrometallurgical methods have been developed. Electro recovery is a method commonly used in the recycling of spent lead-acid batteries, especially for recovering lead from used lead paste. In this process, electrochemical reactions are employed to extract lead from the used paste. This method provides a more environmentally friendly option compared to traditional pyrometallurgy, reducing the risk of environmental pollution and optimizing energy consumption. Hydrometallurgy is the process of extracting metals using water-based solutions. Typically, this method involves grinding the ore and dissolving it in a solution. The hydrometallurgical process for used lead paste includes dissolving lead in the solution and subsequently extracting it from the solution. Hydrometallurgy is preferred over pyrometallurgy in some cases as it operates at lower temperatures and is considered more environmentally friendly. These methods involve a variety of sustainable and environmentally friendly processes, for example, the treatment of paste from spent lead acid batteries by electro-recovery or hydrometallurgy. In this way, environmental pollution can be reduced and energy consumption optimized (Zhang, W., 2016).
The main purpose of pyrometallurgy is to apply a series of heat treatments to the ore to recover precious metals and to cause the material to undergo physical and chemical changes as a result of these processes.
We can review the developments of this method in the last few years. The increasing production of electronic waste, especially waste printed circuit boards (WPCBs), has created a significant need for recycling methods in this field. In recent years, the increasing complexity of WPCBs, such as the inclusion of various materials and multi-metal structures, has made pyrometallurgy stand out as a fast and large-scale treatment method regardless of the waste composition. In this study, the principles of pyrometallurgical methods for WPCB recycling are discussed and various techniques such as thermochemical pretreatment steps, incineration, pyrolysis, and molten salt processing are investigated. Furthermore, starting from the recovery of metals, slag formation, and subsequent processes are described, and alternative methods for polymer and ceramic recovery are examined. Emission control techniques and energy recovery potential are also evaluated. In this context, several developments have been reviewed, showing that pyrometallurgy is a promising candidate for WPCB recycling (Fariborz Faraji., 2022).
Now review some strategies. Xiamen is facing various challenges in municipal solid waste management (MSWM) in China. Among the solutions, strategies such as increasing resource segregation, improving the recycling system, and strengthening the MSWM legislative system are important. In this context, learning from Hong Kong's past successes, integrating technology, environmental factors, and regulatory and institutional perspectives can form the basis of a comprehensive waste management plan. These strategies represent important steps towards achieving a sustainable transformation in waste management. Based on the data we obtained while researching waste management in Xiamen, the rapid urbanization is correlated with the significant growth in Municipal Solid Waste (MSW). The average annual growth rate of MSW is approximately 10.36%. As of 2020, the city’s MSW production reached an average of 6597 tons per day. This growth is attributed to the swift increase in population, currently standing at 5,160,000. In 2020, waste sorting and classification yielded promising results with an average of 1530 tons per day identified as recyclable materials (Kurniawan, T. A., 2021)
Now let's examine innovative solutions in recycling and technology in construction. The new concrete recycling technology developed as part of the C2CA project takes an important step forward in addressing environmental challenges and increasing sustainability in the construction industry. The technology involves the integration of smart demolition, autogenous mill grinding, and dry classification technology called ADR. A demonstration project in the Netherlands focuses on in-situ processing of EOL concrete and investigating the properties of the Recycled Aggregate (RA) produced. The results show that RA substitution, water/cement ratio, and cement type have a decisive influence on the mechanical and durability properties of Recycled Aggregate Concrete (RAC). In this context, improving concrete mix design and using the appropriate cement type can increase the feasibility of using RA in structural concrete. This technology contributes to a sustainable future in the construction industry by offering environmental advantages such as reducing waste and lowering CO2 emissions in cement production (Lotfi, S., 2015).
In conclusion, the amalgamation of recycling and technology presents a promising avenue for addressing the challenges in waste management across various sectors. From the effective handling of composite waste in packaging to the innovative methods for recycling used lead paste, sustainable solutions are emerging. The advancements in pyrometallurgical techniques showcase a versatile approach, particularly in the recycling of electronic waste. Xiamen’s municipal solid waste management challenges underscore the importance of comprehensive strategies, drawing inspiration from successful models like Hong Kong. Additionally, the C2CA project’s concrete recycling technology exemplifies a significant leap toward a more sustainable construction industry.
As we navigate the intersection of recycling and technology, it becomes evident that these innovative approaches not only mitigate environmental impact but also pave the way for a more sustainable and efficient future. Embracing these solutions and fostering international collaborations will be pivotal in building a waste-conscious society and promoting circular economy principles.
References
Krauklis, A. E.; Karl, C. W.; Gagani, A. I.; Jørgensen, J. K. (2021). “Kompozit Malzeme Geri Dönüşüm Teknolojisi—2020’ler İçin En Son Teknoloji ve Sürdürülebilir Kalkınma.” J. Compos. Bilim. 5(1), 28. https://doi.org/10.3390/jcs5010028
Saydaş Plastik. (2021). “Kompozit Atık Nedir? Kompozit Atıkların Geri Dönüştürülmesi.” T.C. Çevre ve Şehircilik Bakanlığı Yetkili Kuruluşu. Erişim Tarihi: 13 Aralık 2021. URL: https://saydasplastik.com.tr/
Zhang, W., Yang, J., Wu, X., Hu, Y., Yu, W., Wang, J., Dong, J., Li, M., Liang, S., Hu, J., & Kumar, R. V. (2016). Yazarlar, finansman desteğini Ulusal Bilim-teknoloji Destek Planı Projeleri (2014BAC03B02), inovasyon fonunun uluslararası teknoloji işbirliği planı, Huazhong Bilim ve Teknoloji Üniversitesi (HUST, 2013ZZGH015), Wuhan Bilim ve Teknoloji Planlama Projesi'nden almıştır. Yenilenebilir ve Sürdürülebilir Enerji İncelemeleri, 61, 108-122. (https://www.sciencedirect.com/science/article/abs/pii/S1364032116002811)
Fariborz Faraji, Rabeeh Golmohammadzadeh, Christopher A. Turşu. "Potential and current applications for recycling waste printed circuit boards: A review of recent developments in pyrometallurgy." Çevre Yönetimi Dergisi, Cilt 316, 15 Ağustos 2022, 115242. https://doi.org/10.1016/j.jenvman.2022.115242. https://www.sciencedirect.com/science/article/abs/pii/S0301479722008155
Kurniawan, T. A., Lo, W., Singh, D., Othman, M. H. D., Avtar, R., Hwang, G. H., ... Shirazian, S. (2021). A societal transition of MSW management in Xiamen (China) toward a circular economy through integrated waste recycling and technological digitization. Environmental Pollution, 277, 116741. https://doi.org/10.1016/j.envpol.2021.116741
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