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Influence of metal‐wustite separation on the reduction of wustite with hydrogen
Author(s) -
Barin Ihsan,
Leber Siegward,
Lemperle Michael
Publication year - 1985
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.198500619
Subject(s) - wüstite , chemistry , hydrogen , metal , catalysis , thermodynamics , inorganic chemistry , oxide , organic chemistry , physics
The reduction rate of wustite with hydrogen at 1133 to 1233 K and for hydrogen pressures between 1.6 and 5 mbar has been measured gravimetrically upon varying the separation between tablets made of wustite and iron or nickel. The reduction rate of wustite is increased by a factor 2.4 prior to precipitation of iron on wustite when the wustite‐metal distance is changed from 2 mm to 0.35 at H 2 pressures of 1.6 mbar and 2.3 mbar respectively. It has thus been demonstrated for the first time, that the catalytic effect of the metal phase on wustite reduction also exists when metal and wustite are separated. To describe this catalytic effect mathematical relations have been derived on the basis of a reaction model. These relations are in good accord with the results of the measurements. From recently published experimental findings, it may be concluded that, as a result of heterogeneous reactions, translationally ‘hot’ H 2 molecules are desorbed from the metal surface. These induce a rapid reaction at wustite unless they have been deactivated by molecular collisions within the bulk gas between the tablets.