Electric arc furnaces (EAF) use scrap metal directly as their primary raw material, thereby offering significant carbon footprint savings – up to 90% compared to traditional integrated steelmaking methods. This route is the fastest way to produce near-zero emission steel, as long as green electricity is used. Nevertheless, there is great potential for optimizing electric steelmaking in terms of product quality and efficiency.
Scrap management and product quality
When recycling steel scrap in an EAF, tramp elements such as copper, tin, and lead cannot be eliminated by the melting process, compromising the final product’s quality by reducing ductility and causing brittleness. To produce high-quality steel from scrap, advanced sorting, blending, and processing techniques are essential when it comes to meeting stringent quality standards and thus enabling premium-grade steel production.
The X-Pact® Metallics Optimizer enhances efficiency by optimizing the use of scrap and metal materials, ensuring an effective mix, higher quality, and better resource utilization. It selects the lowest-cost charging mix for the target steel grade, verifying and updating tramp element assumptions in real time. This iterative process results in consistent, high-quality output with reduced energy consumption.
For a backward analysis of scrap composition, the X-Pact® Sampler provides reliable data for optimizing the charge mix and improving yield. This advanced robotics application automates liquid steel sampling, including sample handling and lance deformation compensation, and is fully integrated into the main automation system.
Maximizing yield and energy efficiency
Maximizing yield and optimizing energy efficiency are crucial for ensuring cost-effectiveness and environmental sustainability in electric steelmaking. Our automatic slag door concept, Condoor®, paved the way to the first concept of unmanned operation years ago. As a slag valve control system, Condoor® manages the slag volume and atmosphere in the EAF. By precisely controlling these parameters, it reduces material losses, improves overall yield, optimizes energy consumption, and reduces electrode usage. Condoor® can also be retrofitted in existing facilities, making it the perfect solution for modernization projects. Its design allows it to work with all types of solid and liquid raw material charges, as proven by multiple installations.
A key factor for increasing yield is controlling the slag chemistry inside the EAF. This involves balancing the need to cover the electric arc with slag and recovering iron oxides from the slag back into the steel. This is where Condoor excels, especially when combined with the process control suite developed by SMS.
In view of the huge demand for electricity in the production of electric steel, every EAF has great potential for optimizing energy utilization and reducing energy consumption. A modern digital energy management system like the Viridis Energy & Sustainability Suite is therefore a must. The Viridis Suite consists of different applications that are tightly integrated, with each application solving specific challenges. This way, the digital solution can improve energy and resource flows in real time. Customers also benefit from functionalities that allow integrating data and transactions for energy contracts. Among other features, the Viridis Suite increases energy efficiency through anomaly detection, and it tracks, reports, and verifies emissions.
For further digital optimization, EAFXpert utilizes data analytics and machine learning to monitor and optimize furnace performance, providing real-time insights and predictive maintenance to minimize downtime and maximize productivity.
Ensuring the electrodes deliver the required melt power regardless of the charge material is the job of the X-Pact® SynReg. Fully configurable and incorporating an extensive historical database, X-Pact® SynReg delivers consistent, optimal performance: fast electrode control, first-touch logic, and arc prediction are some of the functions embedded in the system, leading to better energy efficiency, reduced electrode wear, and lower operational costs.
A further solution that enables high-power melting in weak grid production sites is X-Pact®AURA. Based on IGBT (insulated gate bipolar transistor) technology, it offers a modular design with state-of-the-art power electronics, ensuring maximum efficiency, power density, current stability, dynamic response, and reliability, as well as minimal impact on the electricity network. Moving away from monolithic equipment like heavy-duty transformers and reactors, AURA introduces the concept of modularity, where the required power is reached by a number of parallel cabinets installed in a dedicated room.
X-Pact® AURA powers DC furnaces using fast-switching electronics, enhancing heat transfer and reducing energy requirements through strong vertical stirring of the liquid bath, which avoids stratification inside the shell.
Shaping the future: Innovating for more
Despite all these developments, there is still substantial potential for further innovations, particularly in reducing the carbon footprint to unprecedented levels. One of the most promising innovations is the hydrogen burner, which uses hydrogen instead of fossil fuels, producing water vapor instead of carbon dioxide. In this way, we not only reduce the carbon footprint of the melting process but also boost its efficiency. Following successful laboratory tests conducted as part of an EU-funded project, the hydrogen burner is now being tested in an industrial EAF in Italy and will soon be tested in Spain, to be followed by the more widespread adoption of this innovative technology across the steel industry.
Another groundbreaking solution is Allcharge, a versatile charging system designed to optimize the use of various metal materials, including scrap and DRI. Allcharge ensures the most efficient and effective input mix to achieve consistent quality and yield. By optimizing the charge, Allcharge helps to reduce energy consumption and minimize waste, further contributing to sustainability goals. Compared to other solutions, SMS Allcharge operates without preheating the scrap, limiting dioxins, VOC, and CO emissions. Additionally, the flat bath operation, which is enabled by sidewall charging, results in reduced NOx emissions and less impact on the power grid.
