高炉の炉内反応速度

Abstract

Indirect reduction of iron ores, gasification of cokes, direct reduction of molten wustite, reduction of silica in slag and desulfurization of pig iron have been analyzed and these rates of reactions are determined as the function of properties of materials in the furnace and the operating conditions. For the indirect reduction of iron ores, Eq. (6) of the over-all rate of reduction is obtained, assuming that the diffusion through the gaseous film around the iron ore, the intraparticle diffusion and the chemical reaction proceed in a serial process. Rate determining steps are examined and the results are illustrated in Figs. 3 and 4. For gasification of cokes, using effectiveness factor Ef, the over-all rate of reaction is derived as Eq. (23). Eq. (32) for the rate of reduction of molten wustite is determined, assuming that the reaction is of the second order with respect to wustite in slag. Reduction of silica is analyzed in the upper zone from the tuyere level, and the rate of this reaction is given as Eq. (39). For the desulfurization of pig iron in the hearth, apparent velosity constants are determined as Eq. (45) and (46), considering the reaction between the slag layer and the molten iron flowing through it and the reaction between the layer surface and the iron bath, respectively. These equations of the rate of reaction will be applied to a mathematical model of the blast furnace in the forthcoming reports.