Investigation of sponge iron (DRI) usage in steel plants equipped with induction furnace

In steel production factories, mill scale formation occurs on the steel surface at every point where the steel comes into contact with the air, starting from the mould exit of the continuous casting machine, at the entrance of the rolling mill annealing furnace and afterwards. Mill scale material has been separated as a waste in steel plants for years, however it becomes to be considered as an iron source as it includes iron oxide in the range of between 70 and 80 %. In this study, the use of mill scale obtained from continuous casting machine and rolling mill in induction furnaces in the form of briquetting with anthracite, bentonite and organic binder was investigated. The resulting briquettes are called sponge iron, and chemical analysis of oxide composition was measured by XRF. Phase analyses were analysed by XRD. Scanning electron microscope (SEM) and optical microscope have been used for microstructural studies. XRF analyses of steel and slag of induction furnaces were performed after the mill scale in sponge iron was reduction at the appropriate temperature with anthracite. According to the chemical analyses of steel and slag, it was ensured that the sponge iron was charged to the induction furnace on time and the appropriate sponge iron composition was formed with the raw materials used. It has been ascertaining that sponge iron produced using the mill scale can be used to produce steel in plants with induction furnaces.