As global economies have maintained themselves on linear production models—raw materials, manufacturing, and disposal—the circular economy focuses on redefining processes with the critical principles of reducing, reusing, remanufacturing, and recycling. These principles recognize steel and aluminum—with their unique material properties—as the most recyclable materials globally and central to the circular economy.
The transition to a circular economy transcends the boundaries of steelmaking, encompassing industries such as automotive manufacturing, construction, packaging, and aerospace—sectors that rely heavily on steel and aluminum. Metals recycling companies, electricity providers, and logistics organizations also play pivotal roles in this transformation. Achieving circularity demands a collaborative approach, where every stakeholder’s contribution—whether optimizing processes, reducing waste, or designing recyclable products—is equally vital to creating a sustainable and resource-efficient future.
Introducing a Circular Economy
Interest in the circular economy has steadily grown since the 2000s and peaked with the E.U.’s introduction of the Circular Economy Package in March 2022. However, the concept of recycling has been around for ages. In 1031 Japan, wastepaper was repulped and reused, and it is one of the earliest known examples of recycling in human history. While the circular economy may appear to be a wholly modern invention, historians have noted that most people recycle far more in the past than we do today. Most items were reused and recycled without an established solid waste disposal system. Even in the late nineteenth century in the U.S.A., waste sorting was standard as reusable materials were resold to industries, and organic waste was usually saved to feed livestock.
Recycling had declined by the 1920s in the U.S.A., and waste sorting stopped, except for the metals industry. These attitudes around recycling quickly changed during World War II as the preservation of goods grew in importance. The “throw-away” culture that began in the early twentieth century quickly met with environmental concerns surrounding waste and landfills in the 1960s and 70s. Recycling centers were established in the U.S.A. to enable individuals to sort their waste for themselves, but this relied heavily on individual action. Even today, despite pickup services in many countries, recycling culture and waste sorting vary worldwide.
Returning to the E.U., the European Commission adopted the circular economy action plan in March 2020 as one of the building blocks of the European Green Deal for sustainable growth in Europe. The transition to the circular economy will help reduce pressures on natural resources and contribute to sustainable economic growth and jobs while helping meet the 2050 carbon neutrality target. With aims for carbon neutrality emerging worldwide, what is clear is the necessity for regulations to advance a circular economy, and highly recyclable materials, such as steel and aluminum, are integral to such schemes.
The Recyclability of Steel and Aluminum
The future of a sustainable economy and reaching carbon neutrality targets worldwide depends on the recyclability of materials and resources. Currently, pressures to reduce the environmental footprint of the steel and aluminum industries encourage optimization and improvement strategies for existing value chains. As a significant contributor to global carbon emissions, the steel industry is transforming and shifting away from conventional steelmaking routes. Valuable technologies—e.g., the electric arc furnace—are vital to reducing the industry’s carbon footprint. When combined with effective scrap recycling, the electric arc furnace provides steel producers an effective way to reduce their carbon footprint. However, recycling materials like steel involves new challenges and demands additional technologies and improvements to ensure high-quality end products.
One primary challenge in maintaining steel quality during recycling is the appearance of tramp elements in steel, particularly copper. Similarly, returning aluminum to a usable material that is ideally infinitely recyclable is complex and energy-intensive, especially if previously used as an alloying material. Experts emphasize the need for scrap sorting and processing for steel and aluminum to ensure high-quality remanufacturing. When scrap is processed correctly and sorted, steel producers can make high-quality steel grades with significantly reduced carbon emissions using electric arc furnaces powered by renewables.
Realizing a Circular Economy
A circular economy presents an essential aspect of environmentally friendly industry that supports a sustainable relationship between society and the environment. Implementing a “closed loop” circular economy can significantly reduce carbon emissions from steel and aluminum production and environmentally damaging practices in obtaining raw materials. However, the steel industry’s participation in the circular economy extends past steel recycling. It includes the active use of various by-products from the steelmaking process, which play a vital role in other industries and help reduce the total amount of waste from steel production.
The steel industry’s role in a broader scope of recycling includes the reuse of slag in, e.g., the cement industry. In 2019, 11.5 million tons of Europe’s 15.7 million tons of steel slag by-products were recycled. While this number varies worldwide, it demonstrates an awareness of the cross-industrial responsibility to reduce waste. Additionally, global steel demand continues to rise, and global scrap availability lags. Thus, finding harmful by-products and recovering harmful waste products is essential to meeting global demand without destroying the environment.
Fueled by a passion for innovation, technologies such as By-Product Leaching apply leaching techniques from the mining industry to recover up to 90 percent of usable and recyclable materials from residual dust from sinter plants captured by dry dedusting systems. Moreover, as the industry shifts toward electrification, technologies such as the Smelter for iron ore reduction produce a slag like that of the blast furnace, meaning the cement industry can continue to utilize this key material without sourcing more raw materials from mining. Both technologies reduce the reliance on raw materials, and the former helps preserve a synergistic relationship between heavy industries.
With an eye toward carbon emissions and waste reduction, the interconnectedness of heavy industries is becoming more apparent. From the perspective of the circular economy, reusing and recycling waste material can provide new opportunities to reduce reliance on raw materials. Additionally, advances in scrap sorting and processing technologies help create “clean” scrap to remanufacture higher-quality materials and can extend the recycling lifetime of steel and aluminum. The aluminum and steel industries are developing more recycling possibilities for end-of-life products, focusing on raw material recovery, and supplying previously discarded by-products to other industries. The global shift toward the circular economy is well underway, and the aluminum and steel industry are primed to set the stage for the delicate interplay between reduction, reutilization, and recycling.
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