Reduction Mechanism of Iron Oxide-Carbon Composite with Polyethylene at Lower Temperature
Reduction Mechanism of Iron Oxide-Carbon Composite with Polyethylene at Lower Temperature
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DOI：
10.2355/isijinternational.51.9
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发表时间：
2011-01-01
影响因子：
1.8
通讯作者：
Kasai, Eiki
中科院分区：
文献类型：
--
作者：
Murakami, Taichi;Kasai, Eiki
塑料废物可通过热解提供还原气体，如H(2)和CO，从而在还原氧化铁方面发挥重要作用。然而，它们很难用作还原剂，因为塑料的热降解温度明显低于铁氧化物的还原温度。本文研究了复合材料中聚乙烯在较低温度下生成的碳和氢还原氧化铁的机理，以获得较高的聚乙烯还原利用率。还原实验是在升温速率为0.33K/S的Ar-5%N(2)气流下进行的，并对还原过程中生成的气体进行了连续分析。利用这些气体的浓度计算了赤铁矿的还原程度。聚乙烯-石墨-赤铁矿复合材料的产气率峰值温度分别为770、1070和1370K，770K和1070K的峰值来自聚乙烯的反应，1370K的峰值来自石墨的反应。铁矿石比表面积大，聚乙烯还原速度快。因此，当使用针铁矿等比表面积较大的铁矿石时，聚乙烯碳的利用率较高。
Plastic wastes have a potential to play a significant role in the reduction of iron oxides by supplying reducing gases, e.g., H(2) and CO, through pyrolysis. However, they are difficult to use as reducing agents because the thermal degradation temperatures of plastics are significantly lower than the reduction temperatures of iron oxides. In this study, the reduction mechanism of iron oxides by carbon and hydrogen obtained from polyethylene in the composite at lower temperature was studied in order to attain a high utilization ratio of polyethylene to the reduction. The reduction experiments were carried out under an Ar-5%N(2) gas flow with a heating rate of 0.33 K/s, and the gases formed during reduction were continuously analyzed. The reduction degree of hematite was calculated using the concentration of these gases. The peak temperatures of gas generation rate for the polyethylene-graphite-hematite composite were obtained at 770, 1 070, and 1 370 K. The peaks at 770 and 1 070 K originated from the reaction of polyethylene, and the peak at 1 370 K originated from that of graphite. Larger specific surface area of the iron ore leads to fast reduction rate of the ore by polyethylene. Therefore, high utilization rate of carbon derived from polyethylene was obtained when using iron ore with a large specific surface area, such as goethite ore.