Measurement of Hydrogen Reduction Rates of FeO in 2FeO centre dot SiO_2 and CaO centre dot FeO centre dot SiO_2

摘要

Hydrogen reduction rates of FeO in 2FeO centre dot SiO_2 and CaO centre dot FeO centre dot SiO_2 powder are measured at 1173K. The reduction behavior of 2FeO centre dot SiO_2 and CaO centre dot FeO centre dot SiO_2 is not affected by the particle size and the reaction advances almost linearly with time in the early stage of reduction. The reduced iron may aggregate and retard the progress of the reduction in the later stage. The derived values for chemical reaction rate constants under the conditions of a_(FeO) = 1 and true density are 0.6 to 0.8 and 0.7 to 1.3 (nol/(s centre dot m~3 centre dot atm)) for 2FeO centre dot SiO_2 and CaO centre dot FeO centre dot SiO_2, respectively. The values are very small and it is confirmed that the reducibilities of both 2FeO centre dot SiO_2 and CaO centre dot FeO centre dot SiO_2 are very low. The formation of these compounds causes the adverse effect in the sintering process with respect to the reducibility and therefore minimization of SiO_2 content is important in this respect as well as minimum slag in order to realize the improvement in the reducibility of sinters in the blast furnace.