Kabushiki Kaisha Kobe Seiko Sho

Kobe Steel, Ltd.

Yoshimichi Takenaka

Shoji Shirouchi

Kazuya Miyagawa

Isao Kobayashi

Shoichi Kikuchi

Shuzo Ito

Akira Uragami

Osamu Tsuchiya

Shinichi Inaba

Takuya Negami

Toshihide Matsumura

Masakata Shimizu

Masataka Shimizu

Kimio Sugiyama

Kazuo Kunii

Takashi Kujirai

Haruhisa Iwakiri

Takeshi Sugiyama

Takao Harada

Hidetoshi Tanaka

Sumito Hashimoto

Tsunao Kamijo

Makoto Nishimura

Mamoru Onoda

Isao Fujita

Takao Umeki

Kojiro Fuji

Tadao Tsutaya

Fumikazu Kawaguchi

Teruhisa Uehara

A method of making metallic iron in which a compact, containing iron oxide such as iron ore or the like and a carbonaceous reductant such as coal or the like, is used as material, and the iron oxide is reduced through the application of heat, thereby making metallic iron. In the course of this reduction, a shell composed of metallic iron is generated and grown on the surface of the compact, and slag aggregates inside the shell. This reduction continues until substantially no iron oxide is present within the metallic iron shell. Subsequently, heating is further performed to melt the metallic iron and slag. Molten metallic iron and molten slag are separated one from the other, thereby obtaining metallic iron with a relatively high metallization ratio. Through the employment of an apparatus for making metallic iron of the present invention, the above-described method is efficiently carried out, and metallic iron having a high iron purity can be made continuously as well as productively not only from iron oxide having a high iron content but also from iron oxide having a relatively low iron content.

Method and apparatus for making metallic iron

Pellets incorporated with a carbonaceous material of the present invention contain a carbonaceous material and iron ore mainly composed of iron oxide. The maximum fluidity of the carbonaceous material in softening and melting, and the ratio of iron oxide particles of 10 &mgr;m or smaller in the iron ore are within the range above a line which connects in turn points A, B and C shown in FIG. , including the line. This permits the production of pellets incorporated with a carbonaceous material having excellent thermal conductivity and high strength. Reduction of the pellets incorporated with a carbonaceous material produces reduced iron having high strength after reduction and a low fines ratio with improved productivity.

Pellets incorporated with carbonaceous material

Metallic iron containing slag

Pellets incorporated with carbonaceous material and method of producing reduced iron

A carbonaceous material is controlled such that the amount of carbon is from 7 to 60 mass % based on the total amount of iron and Zn in a starting mixture comprising one or more of ducts containing iron oxide and Zn oxide and a binder in an amount to bond the dusts, and water is added to prepare green pellets incorporated with the carbonaceous material. Then, dry pellets prepared by drying the thus prepared green pellets into a reduction furnace, the dry pellets are heated by heat transfer, mainly, radiation such that a temperature elevation rate is from 3 to 13&deg; C./sec within a temperature range from 150 to 900&deg; C. of the pellets, thereby reducing Zn oxide and evaporating Zn, as well as reducing iron oxide to produce reduced iron pellets.

Reduced pellets

A method of producing reduced iron agglomerates capable of preventing oxidation in the surface layer of the agglomerates and obtaining reduced iron agglomerates having a high degree of metallization, by blowing a methane or methane-containing gas to the reduced iron oxide agglomerates incorporated with carbonaceous material at a surface temperature of 1150&deg; C. or higher during movement in a moving hearth heating type furnace at the end of reduction as the final stage of the stagnation period of the agglomerates in the heating furnace.

Method of producing reduced iron agglomerates

A carbonaceous material is controlled such that the amount of carbon is from 7 to 60 mass % based on the total amount of iron and Zn in a starting mixture comprising one or more of ducts containing iron oxide and Zn oxide and a binder in an amount to bond the dusts, and water is added to prepare green pellets incorporated with the carbonaceous material. Then, dry pellets prepared by drying the thus prepared green pellets into a reduction furnace, the dry pellets are heated by heat transfer, mainly, radiation such that a temperature elevation rate is from 3 to 13.degree. C./sec within a temperature range from 150 to 900.degree. C. of the pellets, thereby reducing Zn oxide and evaporating Zn, as well as reducing iron oxide to produce reduced iron pellets.

Method of producing reduced iron pellets

Iron oxide agglomerates incorporated with the carbonaceous material having a particle size within a range of about 10 to 30 nm are prepared upon production of reduced iron agglomerates. Then, the iron oxides agglomerates incorporated with the carbonaceous material were laid thinly at a laying density of less than 1.4 kg/m.sup.2 /mm or lower on a hearth of a moving hearth furnace. Subsequently, the iron oxide agglomerates are heated rapidly such that the surface temperature of the iron oxide agglomerates reaches 1200.degree. C. or higher within one-third of the retention period of time of the iron oxide agglomerates in the moving hearth furnace. Then, the iron oxide agglomerates are reduced till the metallization ratio thereof reaches 85% or higher to form reduced iron agglomerates and then the reduced iron agglomerates are discharged out of the moving hearth furnace. With the procedures, reduced iron agglomerates of a high average quality can be obtained at a high productivity.

Fired iron-ore pellets are disclosed which are prepared by crushing iron ore to be pelletized, mixing a carbonaceous material of grain sizes ranging from 0.1 to 3 mm in diameter to the crushed iron ore in an amount of up to 4% by weight, pelletizing the mixture thus prepared, and firing the resulting pellets; thereby providing pellets throughout each of which is dispersed macro-pores of sizes ranging from 0.1 to 3 mm in diameter at a ratio of up to 25% relative to all pores contained in each pellet.

Fired iron-ore pellets having macro pores and process for producing the

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Kakogawa, Japan

Yoshimichi Takenaka