| Summary: | 碩士 === 國立臺灣科技大學 === 工程技術研究所 === 78 === The purpose of this research was to study the decarburization of residual carbon in iron powder using CO2-Ar mixing gas. The iron powder was obtained by a direct reduction of mill scale with coke. After the reduction, residual carbon was left in the produced iron powder. The carbon existed in forms of iron carbide Fe3C or coke.
The decarburization was studied in a quartz tube reactor. Iron powder with particle sizes of 40-45, 45-60, 60-85 and 120-200. meshes were employed. The experimental reaction temperatures were ranged between 893-923 K and 002 partial pressures were ranged between O.I and 0.4 atm. The effluent gas from the decarburization was analyzed by a G. C. equipped with a thermal conductivity detector.
The experimental results show that particle size affects the decarburization rate very little. The rate of decarburization and iron oxidation both increase with a increase of reaction temperature and CO2 partial pressure. Experimental data have shown the decarburization take place before the oxidation of the iron powder. The decarburization could be divided into two stages. The first stage , with a carbon conversion on between 0-30 %, is called a nucleation stage and is represented by The decarburization is rapid in this stage. The second stage, with a carbon conversion greater than 50 %, is called a shrinking core stage. In this stage the decarburization is slower than the frist stage.
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