Thermische Analyse des Aufschmelzverhaltens von Direct Reduced Iron

To this day, the BF-BOF route dominates the iron and steelmaking industry by 70%. Alternate technologies like DRI-EAF only make up to 5% of the global steel production. At the moment, only countries with high natural gas deposits (e.g.: Iran or Saudi-Arabia) are using direct reduction as a main technology for steelmaking. However, the climate change is going to increase the share of DRI on the global market. DRI can be melted in electric arc furnaces (EAF) bypassing blast furnaces and therefore help to reduce the CO2 emissions for the steel producing industry and therefore assist to accomplish the goals of the Paris Agreement from 2015. This master thesis investigates high temperature behavior of direct reduced iron (DRI) and hot briquetted iron (HBI) in order to understand the chemical reactions and mechanism which will occur when heating up or melting the samples. The thesis contains experiments by using scanning electron microscope, optical microscope, high temperature laser scanning confocal microscope, heating microscope and simultaneous thermal analysis (STA). The results of this thesis show that DRI without carbon melts up at temperatures near pure iron. The gangue will form low melting slag phases between 1100°C and 1200°C. DRI with carbon will decrease its carbon content while heating up as a function of the iron oxide content due to reduction reactions. Carbon monoxide will be emitted as a consequence.