本文利用管狀的石英反應器，研究以CO2-Ar混合氣體對鐵粉殘留碳之脫碳 (Decarburization)反應.此鐵粉由軋鋼銹皮 (Mill scale)與焦炭(Coke)直接還原而得，由直接還原所得之鐵粉中會殘留一些碳，這些碳以雪明碳鐵(Fe3C)及焦炭的形式存在.

實驗分別以粒徑40-45, 45-60, 60-85及120-200 meshes的鐵粉為固體進料。反應的溫度在 893至923K之間，CO2氣體的分壓在O.1至0.4atm之間，脫碳反應後之氣體以氣相層析儀來分析其組成。

由實驗結果得知鐵粉粒徑大小對的，的脫碳反應影響很小，脫碳反應與鐵粉的氧化反應都隨著反應溫度及CO2分壓的上升而增加，從實驗數據中可知CO2對鐵粉的氧化反應是發生在脫碳反應之後.脫碳反應能夠區分成二個階段，第一階段為快速脫碳期，約在脫碳轉化率為 0至30%之間，稱為成核階段 (Nucleaation Stage)。

當脫碳轉化率大於 50%之後，脫碳進入第二階段為緩慢脫碳期稱為縮核階段(Shrinking core stage)。

當脫碳轉化率在30至50%之間，一般稱此區域為過渡區域(Transition region)，此區域並不適用以上兩種脫碳模式。

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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