New Technology of Electric Arc Furnace Steelmaking

New Technology of Electric Arc Furnace Steelmaking

With the improvement of electric arc furnace equipment and the advancement of smelting skills, as well as the development of the power industry, the cost of electric arc furnace steelmaking has been continuously decreasing. Nowadays, electric arc furnace steelmaking is not only used to produce alloy steel, but also many are used to produce general carbon steel. Its proportion in the total steel production of major industrial countries is constantly increasing.

Electric arc steelmaking furnaces are primarily powered by electricity. Electric energy is discharged through graphite electrodes and furnace materials, generating high temperatures of up to 2000-6000 ℃. The scrap steel raw materials are melted through arc radiation, temperature convection, and heat conduction. During most of the time when the furnace charge melts, the high-temperature heat source is surrounded by the furnace charge, and the heat loss caused by high-temperature exhaust gas is relatively small, resulting in higher thermal power than other steelmaking equipment such as converters. In addition, electric heating is easy to accurately control the furnace temperature and can perform heating operations under any conditions such as oxidation atmosphere or recovery atmosphere, normal pressure or vacuum according to process requirements.

The steelmaking electric arc furnace mainly uses molten iron and scrap steel, and the cost comparison between scrap steel and molten iron is the primary basis for determining the proportion of scrap steel in steel mills. Due to the high production of high-quality special steel in steel mills' electric arc furnaces. Due to the large furnace volume, electric arc furnaces use a wide range of scrap steel materials. In addition to the previous medium frequency furnace material types, there are also heavy waste, medium waste, scrap steel with a thickness of 5 or more, as well as pig iron steel parts, crushed materials, and steel plate materials. The significant difference between the two is that electric arc furnaces rely on their large furnace volume and inherent ability to adjust composition, allowing them to consume pig iron steel parts and produce high-quality steel, with special steel being one of them; However, electric arc furnaces cannot use iron filings that can be eaten before intermediate frequency furnaces, as the adulteration of iron filings is relatively simple, which affects the production cost of steel mills.

Steel mills produce different types and trademarks of steel, so it is important to distinguish them. Therefore, it is incorrect to expect that converter steelmaking can increase or compensate for the gap caused by the removal of intermediate frequency furnace bar steel. It can be partially compensated, but this compensation is calculated based on the national rebar production of 200 million tons. According to the standard of a 5% increase (also considering whether there is enough scrap steel to supply to the converter steel plant), the maximum is 10 million tons.

Electric arc furnace steelmaking is the process of converting electrical energy into thermal energy for melting through a high-density electric arc, with only a small portion of the arc energy being transferred to the furnace charge. From the energy balance, it can be inferred that the conversion of electric thermal energy occurs in the arc column and arc plasma region. 72.5% of the arc power is transmitted to the molten pool, 14.5% enters the electrode, and 13% is transmitted to the furnace wall. This ratio primarily depends on the arc length and slag thickness.

After measuring the melting speed (calculated based on the steel output per minute of electrification time), it was found that there has been a significant improvement in the production power of the electric furnace. Each furnace of steel reduces the carbon increase by 50-100kg/furnace, while the FeO content in the slag only decreases slightly. The use of rubber to discard tires has little effect on sulfur content.