Steel in the circular economy

　　Among the main materials used today, steel is one of the materials that emits the least CO2 per ton of material produced. However, due to the large-scale use of steel, the steel industry must reduce its environmental impact and continue to explore various decarbonization pathways.

　　Reducing CO2 emissions cannot be achieved by one solution alone.

　　The adoption of circularity is an essential part of industrial and societal transformation and an important enabler for achieving the goals of the Paris Agreement.

　　Steel is a permanent material that can be recycled over and over again without losing its properties, making it essential for a circular economy

　　The steel industry is continuing to increase the supply of advanced high-strength steels, which can reduce the weight of steel products and contribute to the development of a circular economy.

　　The circular economy can bring many benefits, including providing durable goods to society, providing local jobs, reducing carbon emissions, and conserving raw materials for future generations.

　　Reduction

　　It refers to reducing the amount of materials, energy, associated waste and other resources used in the production of steel, and reducing the weight of steel used in products. Living the philosophy of "doing more with less".

　　Reduce the use of steel products

　　Over the past 50 years, the steel industry has invested in research and technology to develop new grades of advanced ultra-high strength. These steel grades have greatly reduced the weight of many steel products. Optimizing product weight is an important part of the circular economy. By reducing weight, the amount of raw materials and energy used in production can be reduced, and the pressure on raw materials can be relieved. Lightweight steel products that utilize high-strength steel, such as automobiles, also produce fewer emissions during their life cycle.

　　In the construction industry, replacing ordinary steel with high-strength steel reduces CO2 emissions by about 30% for steel columns and about 20% for steel beams due to the reduction in tonnage of steel products required to meet the same function. Whether it's wind turbines, construction panels, automobiles or steel tanks, using high-strength steel means that less steel can achieve the same strength and functionality. At the same time, this reduces the amount of other materials required (e.g. in foundation engineering), which can have a knock-on effect. In addition, the development of better coating systems can lead to longer service life and thus less material requirements.

　　Sharing economy

　　In the sharing economy, individuals enjoy goods by renting instead of buying. Today, on-demand services such as Uber and Didi Chuxing are gaining popularity.

　　By maximizing the utility of existing products, you can save energy and raw materials by avoiding the need to make more, unnecessary products.

　　With their durability, strength and environmental potential, steel products play a crucial role in this new, more sustainable economy.

　　Reduction in the steel production process

　　Since 1900, the global steel industry has recycled more than 25 billion tonnes of steel, which has reduced iron ore consumption by an estimated 33 billion tonnes and coal consumption by 16 billion tonnes. At the same time, energy use in the steel industry has been significantly reduced. Today, only 40% of the energy used to produce a tonne of steel is 1960. In the same period, steel production increased nearly sixfold.

　　For the steel industry, it is becoming increasingly important to promote the replacement of fossil fuel energy with renewable energy.

　　Another area where the steel industry and its customers are working to improve is working with them to reduce yield losses in downstream manufacturing processes.

　　By working together to reduce the proportion of offcuts and remelt them to make new steel, they will increase productivity and save energy and resources.

　　Reduction is achieved by improving material efficiency

　　Today, material efficiency is an important part of the modern steelmaking process. Our goal is to make the most of all raw materials and ensure that the steelmaking process does not produce any waste. This goal ensures that almost every co-product produced by the steelmaking process can be used in the manufacture of new products. This approach minimizes the amount of waste sent to landfills, resulting in lower emissions and less raw materials. Slag is a co-product of the steelmaking process (electric arc furnace, blast furnace and basic oxygen furnace) and can be used to produce a variety of products such as cement, fertilizer, road construction stone, etc. Process gases from ironmaking, coking and steelmaking processes are often used within steelmaking plants and can be used in place of steam and electricity, or fed into the local grid. Due to the high metal content, other co-products such as dust can also be fully utilized. Water circulates and flows within the steel mill and is mainly used for cooling purposes. Around 90% of the water used in the steelmaking process is purified and can be reused or returned to its source.

　　Valuable co-products such as slag, dust and process gases can be fully utilized in other sectors and industries, avoiding the use of primary feedstocks such as cement clinker and the need for power generation.

　　Over the past few decades, the steel industry has made great strides in the field of waste management. By working with external partners, around 97% of the steel industry's solid and liquid products are marketable and only 3% of the waste is generated.

　　Material (utilization) efficiency of steel production

　　recycle

　　Reuse is the reuse of an object or material for its original purpose or a similar purpose, without significantly altering the physical form of the object or material.

　　Reuse in steel applications

　　Steel is durable, so many steel products can be reused at the end of their useful life. Through reuse, it is possible to extend the life of the product while avoiding the need to transport and remelt steel and make new products. This is very good for the environment and also maximizes the use of resources. In a fully circular economy, the reuse of manufactured goods is considered at the initial design stage of product production.

　　In this way, both small and large products can be quickly and efficiently repurposed for other purposes after their initial use has been completed.

　　For example, when designing high-speed rails, consider switching to low-speed rails when they wear out to a certain extent and are no longer suitable for high-speed lines.

　　Reuse in construction

　　Architecture is the best example of reuse. If you want to conserve resources, it's important to consider reuse in the design of your building.

　　The modular design adopts the steel structure construction method and detachable connections (screws, bolts), so that the building can be quickly transformed and used for other purposes according to the change of demand, which is both cost-saving and does not need to be remanufactured. For example, a community might build a school to meet the needs of a growing population.

　　As the needs of the community change, interior walls can be removed to create open spaces that are suitable for office needs. After a few decades, the space can be redivided and transformed into a nursing home. Integrating reuse into economic activities can open up many new opportunities for consumers and steel companies.

　　In the current business model, buildings are usually built with new steel beams because steel companies guarantee the quality and strength of steel beams. In economies where reuse models are very mature, steel companies will continue to examine new business models and may offer services such as inspection and recertification before reusing old steel beams. Keeping records of the chain of custody ensures that parts are used effectively and that product quality is assured.

　　In this case, builders have the security they need, building owners have a low-cost and quick retrofit solution, and steel companies have a source of income.

　　Remanufacturing

　　Remanufacturing is a standardized industrial process that restores used steel-containing products to like-new condition

　　Remanufacturing of steel-containing products

　　In a truly circular economy, products that have reached the end of their useful life go through a remanufacturing process and then return to like-new condition.

　　The remanufacturing process involves disassembling the product and thoroughly cleaning each component during the dismantling process, inspecting for damage, repairing or replacing it with a new or upgraded part.

　　The product is then reassembled and tested to ensure that it performs at least to the original technical standards. The purpose of this is to reuse a new product that is guaranteed to perform as well as or better than the original product.

　　Remanufacturing is not the same as repair and refurbishment; Repairs and refurbishments are limited to bringing the product to a serviceable state, not to completely restore it. The remanufacturing model has been widely used in many industries, including construction, agricultural machinery, truck and car engines, electric motors, household appliances, and wind turbines. Remanufacturing takes advantage of the durability of steel components and ensures that only faulty or worn components are replaced or repaired, without having to re-produce all components, thus ensuring the associated energy savings.

　　Once re-certified, the remanufactured product is as good as new and can continue to be used for a longer period of time.

　　One of the main factors restricting the development of the remanufacturing model is people's lack of awareness and confidence in remanufactured products. Consumers are accustomed to the "make-use-dispose" linear economic model commonly adopted in advanced economies and may be reluctant to use remanufactured goods. There is still a serious lack of awareness of the social, economic and environmental benefits of the remanufacturing process. However, there are many drivers that can accelerate the adoption of remanufactured products.

　　The steel industry can do something to enable manufacturers to design their products with disassembly and remanubling in mind.

　　Ensuring parts are modular, standardized, and easy to disassemble means they are more likely to be repaired and remanufactured.

　　An example of the benefits of remanufacturing

　　• The return on investment has increased substantially

　　• Customers save 25% to 50% of the cost

　　• Energy savings of 80%

　　• Significant savings in raw materials

　　recycle

　　At the end of the product's useful life, the scrap from the product is melted to make new steel. The recycling process changes the physical form of the steel object, so recycled materials can make new products while maintaining the inherent properties of the original steel.

　　Steel recycling: properties and benefits

　　Ever since the first steel was smelted, steel has been recycled. All steel scrap is recycled again and again, creating new steel products in a closed material loop.

　　Recycled steel retains the inherent properties of the original steel. These properties can be improved during the steelmaking process or through mechanical processes to produce thousands of advanced commercial steels. The quality of steel products can also be improved through recycling.

　　High-value scrap ensures the economic viability of recycling. Steel is inherently magnetic, so it can be easily and cost-effectively recovered from almost any scrap.

　　As a result, steel is the most recycled material in the world. In 2021, around 680 million tonnes of steel were recycled, thus avoiding more than one billion tonnes of carbon dioxide emissions due to raw steel production.

　　This recycled steel includes both pre-consumer scrap from the production process and post-consumer scrap from steel products at the end of their useful life.

　　While all available scrap has been recycled, the amount of existing scrap is insufficient to meet the demand for new steel products.

　　While many steel products, such as packaging materials and automobiles, have a short- to medium-term lifespan, large products such as buildings, bridges, and are designed to last for decades or centuries.

　　In the future, all of these steel materials will be recycled to meet the growing demand for low-carbon steel.