水素・水蒸気混合ガス中の水蒸気濃度を連続的に低下させたときの酸化鉄微粒子の還元反応

抄録

By gradual decrease in the partial pressure of watcr-vapor in H₂-H₂O mixtures at 900°C, the powders of sintered hematite were reduced step by step, i. e., first magnetite then to wustite and finally to iron. The variations of both the gas composition and fractional reduction were measured simultaneously.
Except in the wustite range, the reduction rates obtained under such continuous changes of gas composition were found to be nearly equal to those obtained by the reduction of the pre-reduced magnetite under constant gas concentrations.
When the partial pressure of water-vapor at the start of the reduction was low, the reduction rates under continuous changes of gas composition were nearly equal to those obtained by reducing the pre-reduced wustite or the original hematite sample under constant concentration.
In the wustite range, however, the reduction rates under continuous changes of gas composition became extremely low, especially when the change in partial pressure of water-vapor in the reducing gas became slow. It was found that iron was not produced, when the ratio of partial pressure, PH₂O/ (PH₂+PH₂O), was decreased very slowly and then kept even for two hours at 0.343 which was far less then the equilibrium ratio, 0.388.