The Reduction and Melting Behavior of Carbon Composite Iron Ore Pellet on High Temperature

Matsumura, Toshihide; Takenaka, Yoshimichi; Shimizu, Masakata; Negami, Takuya; Kobayashi, Isao; Uragami, Akira

doi:10.2355/tetsutohagane1955.84.6_405

Cited by 30 publications

(16 citation statements)

References 2 publications

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“…It clearly reveals the process of slag separation during molten iron production from carbon composite iron ores, which has not been verified by the previous studies. 1,2,5) The change of the contact angle from small value to large one means that the interface energy between slag and Fe must be increased after Fe melting. Namely, the change of the interfacial energy of iron/slag due to the Fe melting could determine the molten slag behavior.…”

Section: Methodsmentioning

confidence: 99%

“…Some authors have found the separation of CaO-SiO 2 -Al 2 O 3 molten slag from pig iron, while others reported the covering of FeO containing slag with it. 1,3) It implies that the composition of a molten slag may determine the behavior of a molten slag separation from molten iron. However, details of the mechanism of the molten slag separation have not been established.…”

Section: Introductionmentioning

confidence: 99%

“…Several researchers [1][2][3][4][5][6][7] have investigated the carburization and melting of iron in the mixture of powdery carbonaceous materials and iron ores. It has been known that iron melting rate is very high because of the direct contact of the iron with carbonaceous material as well as the small size of reduced iron particles.…”

Section: Introductionmentioning

confidence: 99%

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The Role of Molten Slag in Iron Melting Process for the Direct Contact Carburization: Wetting and Separation

Kim

Sasaki

2010

ISIJ Int.

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Rapid iron melting initiation and molten slag separation which take place in carbon composite iron ores are quite interesting phenomena, but their mechanisms have not been established yet. Since the size of carbonaceous material and iron ore particles is tiny in carbon composite iron ores, molten slag can dynamically play a critical role in the iron melting initiation and the slag separation. The behavior of the molten slag was clarified by direct observation of phenomena occurring in a simplified carbon composite agglomerate sample (iron disk-slag particle-graphite or coke particle) via a confocal laser scanning microscope combined with an image furnace. It was found that the molten slag wetting induced the iron melting initiation by attracting graphite or coke to iron and the molten slag separation took place with iron melting propagation. However, the high content of coke ash could suppress the iron melting initiation. In addition, the mechanism of molten slag separation from Fe-C melt was verified by phase field modeling.KEY WORDS: iron melting initiation; slag wetting; slag separation; coke ash; carbon composite iron ore; confocal laser scanning microscope; phase field method. 1099© 2010 ISIJ ExperimentalIron disks (diameter: 1.0 mm, purity: 99.99%) were prepared by polishing sliced iron particles from an iron rod. Thickness of the iron disks was 0.5 mm. Graphite disks (diameter: 1 mm; high purity) were made by punching a graphite plate (thickness: 0.5 mm). Cokes fragments (mesh: Ͻ1.0 mm) were prepared by crushing the original cokes (mesh: Ͻ60 mm), whose composition is given in Table 1. In order to know the ash effect on the wetting behavior, higher ash content containing cokes were made by the reaction of the broken cokes particles with CO 2 gas at 1 273 K for 20 min. Slag was prepared by heating mixture of oxide powders (CaO: 22.2%, Al 2 O 3 : 15.1%, SiO 2 : 62.7%) up to 1 673 K in a platinum crucible by using a muffle furnace. According to a literature, 11) the melting temperature of the slag is around the eutectic temperature, 1 446 K, which was confirmed by direct observation via a confocal laser scanning microscope. A piece of, approximately, 0.8 mg slag was positioned between an iron disk and a graphite disk or a fragment of coke on an alumina plate as shown in Fig. 1(a). The plate was slightly coated with boron nitride by a BN spray in order to prevent the slag from reacting with the alumina crucible. "In-situ" observation of the phenomena within iron, slag and carbonaceous material was conducted. The sample was heated up to 1 523 K at the rate of 200 K/min under the atmosphere of purified Ar. The behavior of the particles and the slag were recorded in a personal computer at a frame rate of 15 frames/s.The present experiment consisted of two sub-experiments. The first one was designed that the wetting behaviors of CaO-Al 2 O 3 -SiO 2 slag would be compared for different types of carbonaceous material: graphite, coke and reacted coke. Since ash in coke plays a critical role in slag wetting at the in...

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Role of Molten Slag in Iron Melting Process for the Direct Contact Carburization: Wetting and Separation

Kim

Sasaki

2010

ISIJ Int.

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“…When carbon material-containing agglomerated ore is rapidly heated and reduced at high temperatures in the range of 1 350 to 1 500°C, iron and slag start melting in the final stage of the reaction, and gangue minerals can be separated. 216) In the ITmk3 process, heating and reduction are carried out at 1 350°C in a solid state, and the temperature is then raised to 1 400 to 1 450°C at the end of the reaction. Therefore, melting and separation of slag from the metal occur in the furnace, and the FeO content of the molten slag is a low 1% or less.…”

Section: Rotary Hearth Furnacementioning

confidence: 99%

Ironmaking Technology for the Last 100 Years: Deployment to Advanced Technologies from Introduction of Technological Know-how, and Evolution to Next-generation Process

Naito

Takeda²,

Matsui³

2015

ISIJ International

106

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The 150 year history of the Japanese steel industry dates from the first western blast furnace, which was built by T. Ohashi in 1857. Modern blast furnace operation at integrated steel works in Japan started in 1901 with the first blow-in of Higashida No. 1 blast furnace at Yawata Steel Works. Throughout the prewar and postwar periods, the steel industry has supported the Japanese economy as a key industry which supplies basic materials for social infrastructure and development.After the period of recovery following the destruction caused by World War II, Chiba Works of Kawasaki Steel Corporation (now JFE Steel Corporation) was built and began operation in 1953 as the first integrated steel works in the Keiyo Industrial Region after the war. During Japan's period of high economic growth, many coastal steel works with large blast furnaces having inner volumes of more than 3 000 m 3 and even 5 000 m 3 were built to enable efficient marine transportation of raw materials and steel products. Japanese steel makers introduced and improved the most advanced technologies of the day, which included high pressure equipment, stave cooler systems, bell-less charging systems, etc. As a result, Japanese steel works now lead the world in low reducing agent rate (RAR) operation, energy saving, and long service life of blast furnaces and coke ovens.Following the Oil Crises of the 1970s, the Japanese steel industry changed energy sources from oil to coal and implemented cost-oriented operation design and technology. In 2012, the Japanese steel industry produced approximately 80 million tons of hot metal from 27 blast furnaces, including large-scale furnaces with inner volumes over 5 000 m 3 . During this period, the industry has faced many economic and social challenges, such as the high exchange rate of the yen, oligopoly in the mining industry, global warming, and the surge in iron ore and coal prices driven by the rapid growth of the BRICs. The industry has successfully responded to these challenges and maintained its international competitiveness by developing advanced technologies for pulverized coal injection, expanded use of low cost iron resources, recycling for environmental preservation, and CO2 mitigation.In this paper, the prospects for ironmaking technologies in the coming decades are described by reviewing published papers and looking back on the history of developments in ironmaking during the last 100 years.

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“…[1][2][3] The process completes quickly within 15 min the following reactions of iron ore reduction, smelting reduction, iron carburization and slag separation. This process has a great advantage in energy saving compared with the conventional ironmaking process, because the conventional one requires about 6-8 h for pig iron production.…”

Section: Introductionmentioning

confidence: 99%

Carburization Degree of Iron Nugget Produced by Rapid Heating of Powdery Iron, Iron Oxide in Slag and Carbon Mixture

et al. 2008

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The Reduction and Melting Behavior of Carbon Composite Iron Ore Pellet on High Temperature

Cited by 30 publications

References 2 publications

The Role of Molten Slag in Iron Melting Process for the Direct Contact Carburization: Wetting and Separation

The Role of Molten Slag in Iron Melting Process for the Direct Contact Carburization: Wetting and Separation

Ironmaking Technology for the Last 100 Years: Deployment to Advanced Technologies from Introduction of Technological Know-how, and Evolution to Next-generation Process

Carburization Degree of Iron Nugget Produced by Rapid Heating of Powdery Iron, Iron Oxide in Slag and Carbon Mixture

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