산화철환원에 대한 첨가물의 역할을 규명하기 위하여 수소에 의한 산화철의 환원속도를 측정하였다. 첨가물로는 Na₂O, MgO, CaO등이 사용되었으며 이들 첨가시료의 환원속도는 일반적으로 첨가물의 이온반경이 커짐에 따라 증가되는 경향을 나타냈다. 그러나 첨가물과 산화철이 고용체를 형성할 때는 이온반경에 관계없이 환원속도는 증가되었다. 산화철 환원에 대한 첨가물의 역할은 산화철（α-Fe₂O₃）의 결합구조와 전자이동기구로서 설명하였다. 즉 첨가물이 산화철구조격자의 interstitial position에 들어갈 때는 산화철보다 더 불안정한 구조를 갖게 되어 환원속도를 증가시키며 octachedral position에 들어갈 때는 α-Fe₂O₃보다 더 안정한 화합물을 형성하여 환원속도를 감소시킨다고 생각된다.

To clarify the role of dopants on the reduction rate of hematite with hydrogen, the losses in weight have been measured for pure and doped hematite. Sodium oxide, magnesium oxide and calcium oxide were used as dopants. The ionic radii of these dopants were larger than that of hematite. The reduction rate of the doped hematite was increased with increasing radius of dopant. However, the reduction rate was not concerned with the radius of dopant when solid solution was formed between dopant and hematite. The role of dopants on the reduction rate were discussed in terms of defect structure of hematite and electron transfer mechanism. When a dopant incorporated in hematite expells the interstitial Fe²⁺ ions to the octahedral position, the structure of the doped hematite turned out to be more defective than that of a normal hematite, and the rate of reduction was increased. When a dopant expels the octahedral Fe²⁺ ions to the interstitial position, the structure of the doped hematite became nearer to the stoichiometric structure than a normal hematite, and the rate of reduction was decreased.