Midrex International B.v. Zurich Branch

Kabushiki Kaisha Kobe Seiko Sho

Midrex International, B.v., Rotterdam, Zurich Branch

Yasuhiro Tanigaki

Shoichi Kikuchi

Koji Tokuda

Shuzo Ito

Isao Kobayashi

Osamu Tsuge

Akira Uragami

Keisuke Honda

Osamu Tsuchiya

David C Meissner

Glenn E Hoffman

Takuya Negami

Kyle J Shoop

Hidekazu Okamoto

Eiichi Ito

Metallic iron nuggets made by reducing-melt of a material containing a carbonaceous reductant and a metal-oxide-containing material, the metallic iron nuggets comprising at least 94% by mass, hereinafter denoted as '%', of Fe and 1.0 to 4.5% of C, and having a diameter of 1 to 30 mm are disclosed.

Metallic iron nuggets

A hearth material is laid in the form of a layer on the hearth prior to supply of a mixture containing a carbonaceous reducing agent and iron oxides onto a hearth of a reduction melting furnace, thereby forming a renewable hearth capable of being renewed, and the metallic iron is produced while renewing a part or the whole of the renewable hearth, which has deteriorated during operation, with the hearth material.

Method for producing metallic iron

The present invention is directed to a method of producing granular metallic iron, including: heating a formed raw material comprising a carbonaceous reductant and a substance containing iron oxide in a reduction melting furnace to subject the iron oxide contained in the formed raw material to solid-state reduction; and carburizing reduced iron resulting from the solid-state reduction with carbon contained in the carbonaceous in the formed raw material and causing resulting molten metallic iron to coalesce into the granular metallic iron, wherein an atmospheric gas present in proximity to the formed raw material in the carburizing and melting step has a reduction degree of not less than 0.5. The present invention is also directed to a method of producing metallic iron, including forming a deposit layer containing slag produced in the reduction melting process on hearth refractories, thereby protecting the hearth refractories while producing the metallic iron. The present invention is further directed to a device for supplying an auxiliary raw material to a hearth of a moving hearth type reduction melting furnace adapted to produce metallic iron, the device including a supply duct vertically connecting with a ceiling portion of the furnace.

Method of producing metallic iron

The present invention provides a method of producing metallic iron nuggets with a high yield and good productivity, and more particularly a method which can produce metallic iron nuggets which have a high Fe purity and are excellent in transporting and handling due to a large grain diameter with a high yield and good productivity, when they are produced by reducing and melting raw material containing iron oxide such as iron ore and carbonaceous reducing agent such as coke. The method of producing metallic iron nuggets comprises steps of: heating raw material containing carbonaceous reducing agent and iron oxide-containing material in a reducing/melting furnace, reducing iron oxide in the raw material, and then heating and melting the metallic iron produced by the reduction and simultaneously making it coalesce while separating the metallic iron nuggets from slag components characterized in that the fixed carbon content ratio as the carbonaceous reducing agent is at least 73% and the volatile matter content in the raw material is not more than 3.9% are used, and the mixing content of carbonaceous reducing agent is restrained to be not more than 45% in relation to the iron oxide components, which is contained in the iron oxide-containing material of the raw material.

Method of producing iron nuggets

A method of manufacturing a molten metal iron by charging a starting material at least comprising a carbonaceous reducing material and an iron oxide-containing material into a rotary hearth furnace, reducing under heating the charged starting material into a solid reducing iron, carburizing the metal iron in the solid reduced iron with the carbon ingredient in the carbonaceous reducing material, thereby melting the metal iron, separating the slag ingredient contained in the starting material by the melting, and discharging the molten metal alloy in the molten state as it is to the outside of the rotary hearth furnace for recovery, wherein a downward inclined surface is disposed at an angle 3 to 30&deg; relative to the horizontal plane on the upper surface of a hearth of the rotary hearth furnace on which the starting material is placed, and the molten metal iron is discharged at the discharging position for the molten metal iron from the lowest portion of the inclined surface.

Method of manufacturing molten metal iron

A process comprising: charging a raw material compacting substance containing a carbonaceous reducing agent and an iron oxide contained substance into a moving hearth type furnace; reducing the raw material compacting substance to a reducing ratio 30 to 80% within the reducing furnace to thereby form a shell formed of metal iron or forming a state that a shell formed of metal iron or metal iron are stretched around in a network fashion and a carbonaceous reducing agent remains in a clearance therebetween; agglomerating produced slag containing FeO therein; charging the compacting substance reduced into a melting furnace in a state maintaining a high temperature, and carrying out final reducing and melting to obtain molten meal iron.

Process for manufacturing molten metal iron

The present invention is an apparatus and method for the direct reduction of iron oxide utilizing a rotary hearth furnace to form a high purity carbon-containing iron metal button. The hearth layer may be a refractory or a vitreous hearth layer of iron oxide, carbon, and silica compounds. Additionally, coating materials may be introduced onto the refractory or vitreous hearth layer before iron oxide ore and carbon materials are added, with the coating materials preventing attack of the molten iron on the hearth layer. The coating materials may include compounds of carbon, iron oxide, silicon oxide, magnesium oxide, and/or aluminum oxide. The coating materials may be placed as a solid or a slurry on the hearth layer and heated, which provides a protective layer onto which the iron oxide ores and carbon materials are placed. The iron oxide is reduced and forms molten globules of high purity iron and residual carbon, which remain separate from the hearth layer. An improved apparatus includes a cooling plate that is placed in close proximity with the refractory or vitreous hearth layer, cooling the molten globules to form iron metal buttons that are removed from the hearth layer. The improvements due to the present apparatus and method of operation provide high purity iron and carbon solid buttons, which are separate from slag particulates, and discharged without significant loss of iron product to the interior surfaces of the furnace.

Iron production method of operation in a rotary hearth furnace and improved furnace apparatus

A method of making metallic iron includes heating a mixed powder containing iron oxide and a carbonaceous reducing agent on a hearth to reduce the iron oxide and melt the reduced iron. Preliminary molding of the mixed powder starting material into pellets is not required. The resulting metallic iron contains extremely low concentrations of slag ingredients, even when the mixed powder starting material contains only low concentrations of iron oxide.

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Osaka, Japan

Yasuhiro Tanigaki