Substitutes For Important Raw Material Electric Arc Furnace Smelting (Scrap Steel) :
The main reasons affecting the development of electric arc furnace steelmaking is the lack of scrap steel resources. Alternatives to scrap steel are direct reduction iron (DRI), molten iron (pig iron), decarburized granular iron, iron carbide, and composite metal.
Routinely, there are three sources of scrap steel. |Self-produced scrap steel in the production process of steel enterprises, processing scrap steel in the production process of industrial and mining enterprises, social (production, life, national defense, etc.) scrap steel materials (including scrap steel, such as scrap automobiles, ships, steel bridge, and construction steel).
Because of the progress in technology, the amount of steel scrap produced for the first two reasons decreases and the amount of social steel scrap rises continuously. As social waste steel is reused or contains more harmful elements such as Cu, Sn, As, and Pb which are difficult to remove, some harmful elements are enriched in the steel and the quality of waste steel is reduced. In order to solve the problems of shortage and quality reduction of scrap steel, scrap steel substitutes must be developed. Currently, the main alternatives to scrap steel are:
• Iron carbide
• Decarburized granular iron
• Molten iron (pig iron)
• Direct reduction iron (DRI)
• Composite metal
Iron Carbide :
The basic principle of producing iron carbide is to feed iron ore into a fluidized bed reactor with a certain temperature and pressure and to react with preheated industrial gases (CO, CO2, CH4, H2, H2O steam) to form iron carbide The content of carbon in iron carbide is as high as 6%, which meets the requirements of high carbon distribution in modern electric arc furnace steelmaking.
Decarburized Granular IronIron Carbide :
Fully known as decarburized granulated pig iron, which is produced by quenching with high pressure water when the blast furnace is tapped to produce granulated pig iron from different grain sizes (3-10mm). Then it is loaded into rotary kiln, filled with a certain amount of mixed gas, heated to a certain temperature, and decarbonized by pig iron to obtain the raw material for electric arc furnace steelmaking.
Molten Iron (Pig Iron) :
Correspondingly, the amount of carbon distribution is increased and hot metal (pig iron) is the most effective method. When molten iron is added in large quantities, a large amount of chemical heat is generated due to the elements (mainly carbon) in the molten steel oxidized and for some time during smelting, the power supply is not available, i.e. electric furnace which converts smelting, and even all-iron hydroelectric furnace converting this mode appears in China. New blast furnaces of electric arc furnace process steel plants provide iron to solve the problems of shortage of waste steel resources and high production cost of electric arc furnace process.
Direct Reduced Iron ( DRI) :
Direct reduction refers to the ironmaking process in which iron ore and iron-bearing oxides are reduced to metal products below the melting temperature, usually in a shaft furnace or rotary kiln. According to the product, it can be divided into sponge iron, metalized pellet, and hot-pressed block iron. The production methods include gas-based direct reduction and coal-based direct reduction.
Composite Metal :
At present, 95% of direct reduced iron is used in electric arc furnace production. Direct reduction refers to the ironmaking process in which iron ore and iron-bearing oxides are reduced to metal products below the melting temperature, usually in a shaft furnace or rotary kiln. According to the product, it can be divided into sponge iron, metalized pellet, and hot-pressed block iron. The production methods include gas-based direct reduction and coal-based direct reduction.