Kobe Steel, Ltd.

Kabushiki Kaisha Kobe Seiko Sho

Sumito Hashimoto

Masahiko Tetsumoto

Takao Umeki

Yoshihiro Urabe

Takeshi Sugiyama

Takao Harada

Hidetoshi Tanaka

Koji Tokuda

Shoji Shirouchi

Yoshimichi Takenaka

Hiroshi Uemura

Hiroshi Sugitatsu

Osamu Tsuge

Makoto Nishimura

Tomoki Uemura

Kazuya Miyagawa

Kojiro Fuji

Haruhisa Iwakiri

Teruhisa Uehara

Ryota Misawa

Toshikatsu Uchida

A rotary hearth furnace includes: a furnace body which surrounds a ring-like space; a hearth portion which forms a bottom portion of the ring-like space and is rotatable in the rotational direction; a gas exhaust portion which discharges an exhaust gas generated in the ring-like space to the outside of the furnace body; an introducing portion; and a flow rate regulating portion. The introducing portion is disposed upstream of the gas exhaust portion in the rotational direction and introduces a pressure regulating gas into a non-heating section of the ring-like space. The flow rate regulating portion is disposed between the introducing portion and the gas exhaust portion and regulates a flow rate of a gas by adjusting an opening area of the non-heating section.

Rotary hearth furnace, and method for producing reduced iron using rotary hearth furnace

The present invention provides a method for producing a granular metallic iron in which an adhesion inhibitor leveler, an agglomerate leveler, a discharger, and the physical state of materials present on the hearth are optimized to thereby enable agglomerate to be spread in a single layer. The agglomerate hence is evenly heat-treated to enable high-quality granular metallic iron to be produced in satisfactory yield. The present invention relates to a method for producing a granular metallic iron, which comprises leveling an adhesion inhibitor fed to the hearth of a moving-bed type hearth reducing melting furnace, feeding an agglomerate including an iron oxide-containing material and a carbonaceous reducing agent onto the adhesion inhibitor, leveling the agglomerate fed onto the adhesion inhibitor, subsequently heating the agglomerate to reduce and melt the iron oxide contained in the agglomerate to produce a granular metallic iron, and discharging the produced granular metallic iron using a screw type discharger, wherein the adhesion inhibitor fed to the hearth is evenly leveled using a screw type adhesion inhibitor leveler so that the leveled adhesion inhibitor has a flatness of 40% or less of an average particle diameter of the agglomerate, and the agglomerate fed onto the adhesion inhibitor is evenly laid using a screw type agglomerate leveler so that the agglomerate forms a single layer.

Method for producing granular metallic iron

A rotary hearth furnace includes an exhaust gas eductor. The exhaust gas eductor includes a compartment-defining portion and an exhaust duct. The compartment-defining portion is provided on part of a ceiling of the rotary hearth furnace in an exhaust gas discharge region, and an exhaust duct is connected to the compartment-defining portion. The lower surface of the compartment-defining portion lies higher than the lower surface of the other portion of the ceiling. The compartment-defining portion defines a compartment where the exhaust gas stays. The exhaust duct can include a cooling medium injection nozzle. The furnace increases fuel efficiency by completely burning combustible components remaining in exhaust gas generated in the rotary hearth furnace so as to use the combustible components efficiently for the heating and reduction reaction in the rotary hearth furnace, without problems in producing reduced iron.

Rotary hearth furnace and method of operating the same

A screw conveyor for conveying an object to be conveyed, supported by a casingby rotation of a screw, in which wear of a screw blade and decrease in conveyance efficiency are prevented without the need for extra power. Load on an electric motoror the like for rotating the screwor a value corresponding to the load is measured, and if the value is equal to or larger than a preset upper limit value, a screw shaftis lifted up to increase a gap between an edge of the screw bladeand a bottom portion of the casing

Screw conveyor and operation control method for the same

To provide a rotary hearth furnace which has a simple furnace structure in which the furnace is not damaged even if the furnace is operated for a long term while presenting general equations capable of adequately determining a thermal expansion margin in the rotary hearth furnace.

Rotary hearth furnace

A sealing structure for a solid-transferring screw installed inside a heating furnace such as a material-leveling screw and a product-discharging screw, the sealing structure enabling the solid-transferring screw to be lifted during operation while airtightness of the heating furnace is retained. A driving shaft of the solid-transferring screw passes through through-holes formed in side walls of the heating furnace and is supported by liftable supporting devices disposed outside the furnace. Sealing blocks are attached on outer edges of the through-holes to surround the periphery of the through-holes at the outside of the furnace. Sliding panels are disposed at outer sides of the sealing blocks and have sliding holes for sliding the screw-driving shaft so that the driving shaft extends through the sliding holes. The sliding panels are brought into contact with the sealing blocks via the sealing members therebetween so that the sliding panels are slidable in the vertical direction.

Seal structure of solid feeding screw, and method of manufacturing reduced metal using the seal structure

Rotary hearth furnace and screw thereof for discharging reduced iron

An annular rail is fixed on the lower surface of a moving hearth , and the rail is supported from below by support rollers provided with elevating devices . The moving hearth is continuously or intermittently moved downward by the elevating devices depending on the thickness of a metal oxide layer formed by the deposition of powder of metal oxide agglomerates mixed into the furnace together with the metal oxide agglomerates so that a gap is provided between the surface of the metal oxide layer and the edge of the blade of a discharge screw during operation. A means for preventing the formation of a metal plate and a method for operating the same are provided instead of a means and method including the vertical movement of a discharger for reduced metal, so that the maintenance work can be significantly reduced in a moving-hearth heating furnace, in which metal oxide agglomerates containing a carbonaceous material is placed on a moving hearth, the metal oxide agglomerates are heated and reduced to form reduced metal agglomerates, and the reduced metal agglomerates are discharged from the furnace by a discharger to produce reduced metal.

Moving-hearth heating furnace and method for making reduced metal agglomerates

Heat-treated products discharged from a discharge port of a movable hearth type heat treatment furnace, for example a rotary hearth type reduction furnace are discharged to a sorting means, the heat-treated products that foreign substances have been removed, are discharged through a seal leg into which anti-reoxidation gas is blown from a gas blowing nozzle, to a receiving recess of a receiving pan provided within a case having a hopper attached thereto which is a feeding means, and then a scraper is swung to discharge the heat-treated products deposited on the top surface of the receiving recess from the longitudinal ends of the receiving pan and simultaneously to quantitatively feed it to a molten iron-manufacturing furnace which is a downstream side facility, from the bottom side discharge port of the casing having a hopper attached thereto, and in addition, dust removal/cooling means for produced gas of the molten iron-manufacturing furnace and means for regulating the amount of produced gas are provided.

Discharge apparatus for movable hearth type heat-treatment furnace, its operation method, and method and apparatus for manufacturing molten iron using the same

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

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.

Growing community of inventors

Kobe, Japan

Sumito Hashimoto