Pig Iron – Direct Reduced Iron high temperature microstructural interaction

A steelmaking facility (for making products with low residual levels) is forced to use high-quality high-cost prompt scrap. The alternative is to use a combination of the polluted obsolete scrap along with what is generally referred to as clean iron units, such as Pig Iron (PI) or Direct Reduced Iron (DRI). These are raw materials containing little or no residual elements. Indeed, during the usual practice EAF-based producers use DRI, which is produced by the reaction between iron ore and reducing agents, typically from 20 up to 30 % of the charge weight, to improve the metallic charge by diluting impurities introduced by scrap. Due to this, the world’s direct reduction industry continued its solid growth setting a new record each year and it is expected to grow quite considerably over the next few decades. Since its high carbon content, the charge of PI, typically from 5% up to 60%, results in a significant increase of the carbon content of the resultant steel. Its consequent decarburization, if adequate, allows a maximum recovery energy from CO, since it is an exothermic reaction. This could result as a very important source of chemical energy within the EAF, granting power savings. Moreover, due to the still oxidized 7% volume of DRI, the carburizing environment generated by PI would grant beneficial effects on DRI yield. After the characterization of both pig iron and DRI, testing trials have been performed in order to evaluate their interaction at high temperatures, simulating their behavior within EAF.