2841.     RODE, E. Y. [Iron Oxides and Their Reducibility With Hydrogen and Carbon.]  Jour. Russian Phys.-Chem. Soc., vol. 62, 1930, pp. 1453-1466; Chem. Abs., vol. 25, 1931, p. 2628.

        Heating curve of Fe₂O₃ has a conversion point at 745°, quite likely corresponding to a definite modification of Fe₂O₃.  Beginning with 1,280° some irregularities are observed that probably have a connection with the beginning of loss of O₂.  The temperature curve of reduction of Fe₂O₃ with H₂ has 2 kinks, probably corresponding to 2 steps in reduction, 1^st to Fe₃O₄ and then to a lower oxide.  There is no definite proof of formation of FeO as an intermediate product.  Fe₂O₃ is more easily reduced with H₂ than Fe₃O₄.  In reducing hydrated Fe oxides with H₂ the point where reduction begins could not be ascertained, because it lies in the region of decomposition of corresponding hydrates.  If the products of reduction are cooled in H₂, they become pyrophoric when the heating temperature does not exceed 600°-650°.  A higher heating temperature makes them nonpyrophoric.  Reduction of Fe₂O₃ and hematite ore with C gives on the temperature curve 3 halts, probably corresponding to 3 consecutive stages of reduction to the metal.  Here again Fe₂O₃ is more easily reduced than Fe₃O₄.