With the implementation of various advanced technologies, steelmaking is evolving towards cleaner and more efficient production.
Scrap Crushing and Sorting Technology
Scrap typically consists of ferrous metals, non-ferrous metals, and non-metals. Before being charged into the furnace, scrap must be crushed and sorted. This process not only enables effective separation but also removes most of the paint and coatings from the surface of the scrap.
Scrap Preheating Technology
Preheating scrap can improve energy efficiency. Technologies such as double-shell electric arc furnace (EAF), vertical EAF, and Consteel EAF are capable of preheating. However, due to low waste heat utilization and high maintenance requirements, double-shell and vertical EAFs are less commonly used.
The Consteel EAF system, which features continuous feeding, offers several advantages: minimal impact on the power grid, reliable and controllable feeding, and efficient use of flue gas waste heat. However, it also has drawbacks, such as air leakage through dynamic seals, an extended production line, and high operating costs.
Dioxin Management Technology
Scrap often contains grease, paint, cutting fluids, and other impurities. During EAF steelmaking, these impurities can lead to the formation of dioxins, which cause environmental pollution. Two primary approaches are used to manage this issue: source inhibition and synthesis inhibition.
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Source Inhibition: Involves online detection and manual selection to minimize or eliminate scrap containing chlorine-based materials.
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Synthesis Inhibition: Involves rapid cooling and the addition of catalysts or inhibitors to prevent the regeneration of dioxins. However, this method requires significant investment in equipment.
Waste Heat Recovery Technology
EAF smelting produces large volumes of high-temperature, dust-laden flue gas. This accounts for around 11%—and in some cases up to 20%—of the total energy input. Since EAF operation is cyclical, the recovered heat must be stored to ensure stable and continuous usage, particularly for power generation. Heat storage systems such as molten salt or concrete-based energy storage are used to capture and retain this excess heat.
Smart Batching System
Batching is a key factor influencing both production costs and product quality in EAF steelmaking. Based on the specific EAF parameters, production processes, raw material constraints, and target chemical composition, a mathematical optimization model is developed. This model calculates the most cost-effective charging structure using mathematical programming techniques to achieve intelligent batching.
Electrode Regulation System
Modern automatic electrode control systems can adjust parameters for different smelting stages, offering optimal response time, three-phase imbalance correction, and the ability to insert or remove reactors. These systems support flexible control to adapt to electrode and furnace conditions effectively.
Multifunctional Door Robot
Advanced robotic systems now allow for automatic, real-time probe replacement and online sampling. These robots can measure temperature and oxygen activity in the liquid steel and calculate carbon content automatically, all with one-key operation.
Continuous Temperature Measurement of Molten Pool
Measuring the temperature of molten steel is challenging due to the harsh EAF environment. The non-contact temperature measurement system developed by the University of Science and Technology Beijing (USTB) uses sensors installed in the furnace wall. By injecting multi-element temperature-sensing gas and analyzing its signals, the system can accurately measure and predict molten pool temperatures.
Foam Slag Detection and Control
Foam slag plays a critical role in EAF steelmaking by insulating the molten steel from air, covering the arc, reducing radiant heat loss, and enhancing the conversion of electrical to thermal energy. Effective control of foam slag thickness and retention time is essential during the melting period to ensure optimal energy efficiency and smelting performance.
Furnace Gas Online Analysis
Modern EAF gas analysis systems can measure gas temperature, flow rate, and concentrations of CO, CO₂, H₂, O₂, H₂O, and CH₄. By integrating this data with control models, these systems assess chemical energy utilization, carbon-oxygen imbalance, explosion risks, and ventilation performance. They also support dynamic oxygen input control to ensure complete combustion.
Smart Control of the Entire EAF Process
Process data is collected from various sensors—including exhaust gas analysis, electric harmonics, and current/voltage monitors. A historical process database is used to identify the most relevant past scenarios under similar charging and operational conditions. The system then determines the optimal process strategy with low cost and short melting time.
