Japan started the national project "COURSE 50" for CO2 reduction in the 2000s. This project aimed to establish novel technologies to reduce CO2 emissions with partially utilization of hydrogen in blast furnace-based ironmaking by 30％ by around 2030 and use it for practic-al applications by 2050. The idea is that instead of coke, hydrogen is used as the reducing agent, leading to lower fossil fuel consumption in the process. It has been reported that the reduction behavior of hematite, magnetite, calcium ferrite, and slag in the sinter is different, and it is also considerably influenced by the sinter morphology. This study aimed to investigate the reduction behavior of sinters in hydrogen enriched blast furnace with different mineral morphologies in CO–CO2–H2 mixed gas. As an experimental sample, two sinter samples with significantly dif-ferent hematite and magnetite ratios were prepared to compare their reduction behaviors. The reduction of wustite to iron was carried out at 1000, 900, and 800℃ in a CO–CO2–H2 atmosphere for the mineral morphology-controlled sinter, and the following findings were obtained. The reduction rate of smaller amount of FeO led to faster increase of the reduction rate curve at the initial stage of reduction. Macro-observa-tions of reduced samples showed that the reaction proceeded from the outer periphery of the sample toward the inside, and a reaction interface was observed where reduced iron and wustite coexisted. Micro-observations revealed three layers, namely, wustite single phase in the center zone of the sample, iron single phase in the outer periphery zone of the sample, and iron oxide-derived wustite FeO and iron, or calcium ferrite-derived wustite 'FeO' and iron in the reaction interface zone. A two-interface unreacted core model was successfully applied for the kinetic ana-lysis of the reduction reaction, and obtained temperature dependent expressions of the chemical reaction coefficients from each mineral phases.

Ko-ichiro Ohno;Takayuki Maeda;Kazuya Kunitomo;Masashi Hara

Department of Materials,Faculty of Engineering,Kyushu University,744 Motooka,Nishi-ku,Fukuoka 819-0395,Japan;Kashima Area,East Nippon Works,Nippon Steel Corporation,3 Hikari,Kashima City,Ibaraki 314-0014,Japan

矿物冶金与材料学报

[1]Ko-ichiro Ohno;Takayuki Maeda;Kazuya Kunitomo;Masashi Hara-.Effect of FeO concentration in sinter iron ore on reduction behavior in a hydrogen-enriched blast furnace)[J].矿物冶金与材料学报,2022(10):1820-1829

COURSE,practic,sinters,wustite

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