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Steel production in electric arc furnace steelmaking is growing rapidly
In recent years, the production of steel using electric arc furnaces (EAF) has experienced rapid growth, outpacing the overall increase in global steel output. In 2000, world steel production reached 1,146 million tons, with EAF steel accounting for 283.52 million tons, representing 24.7% of the total. Compared to 1995, EAF steel output rose by 168%, while total steel output increased by 132%. This growth was largely driven by developed countries that have abundant scrap resources and low electricity costs, allowing for the efficient development of EAF technology. For instance, in the U.S. and Japan, EAF steel accounted for 46.8% and 28.8% of their respective total steel outputs in 2000. However, in China, where scrap availability is limited and electricity prices are high, EAF steel production in 2000 stood at 20.2 million tons, making up only 15.9% of the country’s total steel output.
During the 1990s, China saw significant progress in the development of large-capacity, ultra-high-power electric arc furnaces. Previously, most EAFs were used for producing alloy steels, mainly in special steel plants, with capacities generally below 50 tons. From the 1970s to the late 1980s, many small EAFs were built, often paired with small rolling mills to produce low-grade steel. These operations suffered from poor product quality, high energy consumption, and environmental pollution. As a result, the government implemented policies to phase out these inefficient units. By the 1990s, the amount of scrap recovered by small steel mills had dropped to just 5 million tons annually. In response, China began constructing several large-capacity, ultra-high-power EAFs, significantly advancing its EAF steelmaking technology and narrowing the gap with leading global producers. Between 1990 and 1999, 19 high- and ultra-high-power EAFs with capacities ranging from 60 to 150 tons were built, totaling 1,645 tons of capacity. After 2000, more than 50 EAFs with capacities over 50 tons were put into operation. Currently, there are 39 EAFs with capacities above 50 tons, and 10 units with single furnace outputs exceeding 100 tons. These modern EAFs are equipped with ladle refining (LF) systems and continuous casting lines, enabling the production of high-quality steel such as oil pipes, gas pipelines, and boiler tubes. Some facilities also include vacuum degassing (VD) units to ensure superior steel quality and meet customer demands.
To improve steel quality, the charge composition in EAFs has been optimized. Traditionally, EAFs relied solely on scrap steel, which often contained harmful residual elements like lead, tin, arsenic, zinc, and copper. To mitigate this, some plants now add molten iron, direct reduced iron (DRI), or hot briquetted iron (HBI) to dilute these impurities. For example, a 150-ton DC arc furnace used for producing high-strength oil well pipes and boiler tubes incorporates 30% blast furnace hot metal into the charge, effectively reducing the concentration of harmful elements. This approach has proven successful in meeting the stringent requirements for high-quality seamless steel pipes. However, the addition of DRI increases energy consumption during the smelting process.
DC arc furnaces offer several advantages over traditional three-phase AC furnaces, including reduced electrode and refractory consumption, lower power usage, shorter smelting times, less grid interference, no need for dynamic compensation devices, and lower noise levels. The DC current passing through the molten pool generates strong electromagnetic forces, promoting better stirring of the melt and ensuring uniform composition and temperature.
Oxygen-burning technology, particularly the use of oxygen and natural gas, has become a key method for enhancing EAF productivity. This technology has been widely adopted globally and plays a crucial role in the intensified smelting processes of ultra-high-power EAFs. Many Chinese steel plants have optimized their oxygen blowing systems based on specific conditions, resulting in shorter smelting cycles and higher productivity.
The use of high-quality refractory materials has also significantly extended the life of EAF linings. With the rise in power levels, the thermal load on the lining increased dramatically, causing a sharp decline in its lifespan. In the 1980s, EAF linings typically lasted less than 100 heats. To address this, new refractory materials were developed, such as high-alumina bricks for the furnace roof, magnesia-chrome bricks for the side walls, and magnesia-carbon bricks for the slag line. These improvements have greatly enhanced the durability of EAF linings.
In conclusion, China's EAF steelmaking industry experienced rapid development in the 1990s, significantly improving its technological and equipment standards. However, some large EAFs have not fully utilized their capacity due to challenges in localizing key equipment and spare parts. Additionally, high scrap and electricity prices continue to raise production costs, making it essential to reduce scrap prices and energy consumption in the future. Small EAF plants should be phased out to prevent competition for scrap resources and alleviate shortages. Finally, EAF steel mills with appropriate conditions can consider adding molten iron or DRI/HBI to their charges to enhance the quality of high-grade steel.