Crude steel directly from pre-reduced high manganese containing iron ore

Abstract

Considerable reserves of medium grade iron ore deposits are estimated in different localities in Egypt. The main reserve contains harmful impurities such as MnO2, which consumes high rate of coke in the blast furnace process. In this study, crude steel was produced from reduced iron ore sample containing 9·9 wt-% MnO2. High manganese–iron ore samples were reduced isothermally in hydrogen gas at 800–1000°C and the O2-weight loss resulting from the reduction of Fe2O3 to Fe and MnO2 to MnO as a function of time was monitored by applying a thermogravametric technique. The rate of reduction was found to increase with temperature and decreased with time. The apparent activation energy values at different reduction stages were calculated to predict the corresponding mechanism. At the optimum reduction conditions, the reduced product was treated in an electric furnace simulation for the production of low carbon steel and high manganese slag. The partition ratios of manganese (LMn) and phosphorus (Lp) were determined as a function of the slag basicity. It was found that with the decrease in basicity, LMn increased whilst LP decreased. The ratio Mn/Fe obtained in the slag was 1·3, which can be used as a part of the charge to produce manganese-ferroalloy.