TY - JOUR
T1 - Reduction mechanism of iron oxide-carbon composite with polyethylene at lower temperature
AU - Murakami, Taichi
AU - Kasai, Eiki
N1 - Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2011
Y1 - 2011
N2 - Plastic wastes have a potential to play a significant role in the reduction of iron oxides by supplying reducing gases, e.g., H2 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%N2 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.
AB - Plastic wastes have a potential to play a significant role in the reduction of iron oxides by supplying reducing gases, e.g., H2 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%N2 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.
KW - Composite
KW - Ironmaking
KW - Low-grade iron ore
KW - Plastic wastes
KW - Reduction
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U2 - 10.2355/isijinternational.51.9
DO - 10.2355/isijinternational.51.9
M3 - Article
AN - SCOPUS:79956060421
VL - 51
SP - 9
EP - 13
JO - Transactions of the Iron and Steel Institute of Japan
JF - Transactions of the Iron and Steel Institute of Japan
SN - 0915-1559
IS - 1
ER -