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A Kinetic Study on Carbothermic Reduction of Hematite with Graphite Employing Thermogravimetry and Quadruple Mass Spectrometry
Author(s) -
Jung SungMo,
Yi Sang Ho
Publication year - 2013
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201200310
Subject(s) - wüstite , hematite , graphite , thermogravimetric analysis , analytical chemistry (journal) , chemistry , mass spectrometry , thermogravimetry , pellet , materials science , mineralogy , inorganic chemistry , chromatography , organic chemistry , composite material
The reduction of hematite–graphite pellet was investigated from a kinetic viewpoint in the temperature range of 1173–1473 K (900–1200°C). The experimental procedure included thermogravimetric analysis (TGA) for measuring the weight change of the pellet and quadruple mass spectrometry (QMS) for monitoring the compositional change of the product gases. By applying a uniform internal reduction model to the current system, the activation energies for the reduction of Fe 3 O 4 to wustite and for that of wustite to Fe were evaluated to be 91.0 and 25.9 kJ mol −1 , respectively. Due to the product gas analyses by QMS, it was observed that the reduction rate of hematite–graphite pellet was accelerated up to the equilibrium concentration of CO determined by the carbon gasification curve. Changeover of reduction mechanism with increasing reduction degree was explained in terms of a schematic diagram based on the results obtained in the current study.