Refractory for electric arc furnace

Eaf is mainly made of scrap steel as main raw material. Waste steel, lime, etc. are added into the furnace. When electrified, an arc occurs between the electrode and the waste steel, and the charge is heated. A series of metallurgical chemical reactions are carried out to convert the waste steel into steel.

 

With the development of industrialization, the world's iron and steel scrap increased. Especially in recent years, the development of eaf steelmaking in a series of new technologies, such as water-cooled furnace wall, cover and electrode, the oxygen - fuel burner, scrap preheating, eccentric bottom tapping, made of foam slag and ac dc power supply, etc., make the electric arc furnace steelmaking more quickly, more close to the converter, steelmaking costs fall further, less investment, flexible production and led to the further development of electric arc furnace steelmaking. Experts predict that electric and converter will be equal parts of the steel industry in the future. However, as China is a developing country and the industrialization process has just started, a large amount of steel is needed for construction and development, which promotes the development of steel enterprises. But because the electric furnace needs the raw material shortage, restricted the electric furnace development speed. After the rapid development of electric furnace in 1990s, the speed of development was slowed down in China.

 

Compared with that of AC arc furnace, dc arc furnace has the following advantages: electrode can be saved by more than 50%, noise can be reduced by 15%, influence on power grid can also be significantly reduced, energy consumption can be reduced by 5%~10%. So in recent years, dc arc furnace development is relatively fast. Until now, there have been three basic types of DC eAF, namely ABB, Clecim and GHH. Different types of DC arc furnaces are classified according to the different structure of bottom electrode, which shows the importance of bottom electrode. The bottom electrode of THE ABB type DC arc furnace is electrically conductive with a conductive refractory material and the bottom surface is air-cooled; While CHH is embedded with many small steel needles (fine steel rods with a diameter of 20~50mm) at the bottom, and the bottom surface is also wind-cooled. The base electrode of Irsid-Clecim is 1~4 thick steel rods, and the lower end is cooled by copper water jacket. On the basis of these three types, various forms such as steel sheet type, steel bar type with water-jet cooled bottom electrode and steel bar and copper bar composite bottom electrode have been developed.