Return to Abstracts of Literature

Return to Abstracts of Literature 1250-1499

Literature Abstracts

 1452.    ---------------.  [HOFMANN, K.] [Reduction Mechanism of Iron Oxides in a Gas Stream.  II.]  Ztschr. Angew, Chem., vol. 38, 1925, pp. y715-721; Chem. Abs., vol. 19, 1925, p. 3197.

       Blast-furnace process is imitated in a simplified manner, using pure H2 gas and various Fe2O3 and Fe3O4 preparations.  The reaction products are analyzed, and the results are given in curves of H2 adsorption in relation to time and reduction in relation to temperature.  Equilibrium reactions indicate only the tendency of the reaction, because the result is determined by the surface conditions.  Fe2O3 shows 100% reduction at 550° and 1,000°, with minima at 750° (a) and 925° (b).  Granules of 0.05-0.02 mm. diameter are best.  Fe3O4 exhibits the same character, but is harder to reduce (ferric ferrate).  FeO was not found below 564°.  Fe3O4 forms only in slow processes.  The reduction minima are explained (a) by adhesion and (b) by the β-γ transformation.  They can be suppressed by addition of MgO.  Acid admixtures (SiO2) do the same but form irreducible slag above 700°.