Explanation

With iron ore or pellets as raw materials, iron containing spongy pores inside is obtained by reducing and removing oxygen in raw materials with solid or gas reducing agents at a temperature below the melting point of raw materials, which is also called direct reduced iron (DRI). During the reduction process, there is no liquid iron or slag produced, and it is named after the sponge like pores and developed surface inside. Its density is low, the metallization rate is more than 85%, and the content of sulfur, phosphorus and other impurities is low. Industrial production is mainly solid phase reduction method, or direct reduction method. According to production equipment, it can be divided into shaft furnace method (hydrogen and carbon monoxide are used as reducing agents), tubular furnace method (coke powder, lignite, anthracite and other solid carbon are used as reducing agents), rotary kiln method, etc. sponge iron with metallization rate greater than 92% and gangue alkalinity not greater than 0.3 dominated by silica is widely used in electric furnace or converter sleelmaking steelmaking instead of scrap, which can significantly shorten the smelting time and improve production efficiency, reduce the content of non-metallic inclusions and nitrogen in steel and improve the uniformity of steel. Since sponge iron has a strong water absorption capacity, it should be kept dry or preheated before use.

Classification