3327.     TATIEVSKAYA, E. P., CHUFAROV, G. I., AND ANTONOV, V. K.  [Rates of Reduction of Iron Oxides.]  Jour. Phys. Chem. (U.S.S.R.), vol. 24, 1950, pp. 385-393; Chem. Abs., vol. 44, 1950, p. 8209.

        Although the equilibrium pressure, calculated, of O2 over Fe2O3 is much greater than over Fe3O4 or FeO, all 3 oxides are reduced by H2 at similar rates, showing that reduction is independent of dissociation and that reduction of FeO is not the slowest stage in the reduction of higher oxides.  The surface area of the oxides, from N2 adsorption at -195 was 0.85, 0.86, and 0.60 m.2 per gm. for Fe2O3, Fe3O4, and FeO, respectively.  The oxides were heated in H2, the H2O formed was frozen out, and the rate r of reaction was calculated from the decrease in pressure p.  In 1 experiment, v first increased to a maximum at 10-30% reduction and then decreased again.  When the original p(po) was 200 mm. Hg, the maximum v of Fe2O3 was about 7, 16, 37, and 95X10-4 gm. O2 per gm.  Fe2O3 and minimum at 350, 400, 450, and 500, respectively; the maximum v of the other oxides were, for example, 10% less.  At reductions below 10%, v was proportional to pon, and the constant n was at 400 and 450 0.68 and 0.83 for Fe2O3, 0.68 and 0.76 for Fe3O4, and 0.5 and 0.65 for FeO, when po varied 0-320 mm. Hg.  The apparent energies of activation were 16,500, 13,500, and 14,000 cal. per mol.

        TATSUKI, Y.  See abs. 1893, 1904.

        TATUKI, Y.  See abs. 3313.