EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

Coupling the blast furnace with direct reduction processes may increase the BF productivity and flexibility, and contribute to CO2 emission mitigation at an integrated steelworks. Charging of HBI into blast furnaces will be realised this year in Europe. Another way is injection of DRI / LRI via tuyères. In this case, the briquetting step and long residence times in the shaft could be avoided. This study focuses on the reaction behaviour of DRI / LRI fines during injection into a blast furnace by means of the laboratory injection rig MIRI and pilot plant COBESI (Coke Bed Simulator) as well as by mathematical modelling. The effect of particle microstructure, metallization and reduction degrees on reoxidation behavior is discussed. The influence of carbon presence in the pre-reduced material on its conversion and reoxidation under the raceway conditions was investigated. Pilot tests primarily aimed at interaction between injected DRI / LRI and coke in the lower blast furnace zone. Among others, change in coke reactivity was examined. Furthermore, co-injection of iron containing dusts with PC is discussed. Flame temperature while injecting various DRI/LRI-types was calculated using a developed model.