Abstract: The reduced iron manufacturing method of the present invention includes preparing an agglomerate by agglomerating a mixture containing an iron oxide-containing substance and a carbonaceous reducing agent, and preparing reduced iron by heating the agglomerate to reduce iron oxide in the agglomerate, characterized in that Expression (I) as follows is satisfied: Cfix×Xunder105/OFeO?51??(I) where OFeO is the mass percentage of oxygen contained in the iron oxide in the agglomerate, Cfix is the mass percentage of total fixed carbon contained in the agglomerate, and Xunder105 is the mass percentage of particles having a particle diameter of 105 ?m or less with respect to the total mass of particles configuring the carbonaceous reducing agent.

Abstract: A process for manufacturing reduced iron agglomerates which comprises introducing starting agglomerates that comprise both an iron oxide-containing material and a carbonaceous reducing agent onto the hearth of a moving-bed heating furnace, and heating the agglomerates to reduce the iron oxide contained in the agglomerates, wherein the iron oxide-containing material contained in the starting agglomerates has a mean particle diameter of 4 to 23 ?m and contains at least 18% of particles having diameters of 10 ?m or less. By the use of such starting agglomerates, the process attains: an improvement in the yield of reduced iron agglomerates having large particle diameters; a reduction in the manufacturing time, said reduction leading to an enhancement in the productivity; and a remarkable reduction in the content of impurities such as sulfur in the reduced-iron agglomerates.

Abstract: The reduced iron manufacturing method of the present invention includes preparing an agglomerate by agglomerating a mixture containing an iron oxide-containing substance and a carbonaceous reducing agent, and preparing reduced iron by heating the agglomerate to reduce iron oxide in the agglomerate, characterized in that Expression (I) as follows is satisfied: Cfix×Xunder105/OFeO?51??(I) where OFeO is the mass percentage of oxygen contained in the iron oxide in the agglomerate, Cfix is the mass percentage of total fixed carbon contained in the agglomerate, and Xunder105 is the mass percentage of particles having a particle diameter of 105 ?m or less with respect to the total mass of particles configuring the carbonaceous reducing agent.

Abstract: Provided is a technique for increasing the yield of reduced iron, thereby improving productivity when manufacturing reduced iron by heating an agglomerate. This method for manufacturing reduced iron includes: a step in which a mixture is agglomerated, said mixture containing an iron oxide-containing substance, a carbonaceous reducing agent, and a melting point regulator; and a step in which reduced iron is manufactured by heating the obtained agglomerate, reducing and partially melting the iron oxide in the agglomerate, and aggregating the iron component. The particle size of the fine particulate iron generated in the step in which the reduced iron is manufactured is adjusted, and the fine particulate iron is blended into the mixture.

Abstract: Provided is a method for producing a reduced iron agglomerate, which comprises introducing an agglomerate comprising an iron-oxide-containing substance, a carbonaceous reducing agent, a melting point adjuster and an aid for the melting point adjuster onto a furnace bed of a moving-bed-type heating furnace and then heating the agglomerate on the furnace bed to reduce iron oxide in the agglomerate; and melting the resultant product by additional heating to cause the coalescence of an iron component, thereby producing the reduced iron agglomerate, wherein an agglomerate containing the melting point adjuster that has an average particle diameter of 0.3 mm or less and in which the content of a particle diameter of 0.5 mm or less in an amount of 55 mass % or more is used.

Abstract: Provided is a technique for increasing the yield of reduced iron, thereby improving productivity when manufacturing reduced iron by heating an agglomerate. This method for manufacturing reduced iron includes: a step in which a mixture is agglomerated, said mixture containing an iron oxide-containing substance, a carbonaceous reducing agent, and a melting point regulator; and a step in which reduced iron is manufactured by heating the obtained agglomerate, reducing and partially melting the iron oxide in the agglomerate, and aggregating the iron component. The particle size of the fine particulate iron generated in the step in which the reduced iron is manufactured is adjusted, and the fine particulate iron is blended into the mixture.

Abstract: A process for manufacturing reduced iron agglomerates which comprises introducing starting agglomerates that comprise both an iron oxide-containing material and a carbonaceous reducing agent onto the hearth of a moving-bed heating furnace, and heating the agglomerates to reduce the iron oxide contained in the agglomerates, wherein the iron oxide-containing material contained in the starting agglomerates has a mean particle diameter of 4 to 23 ?m and contains at least 18% of particles having diameters of 10 ?m or less. By the use of such starting agglomerates, the process attains: an improvement in the yield of reduced iron agglomerates having large particle diameters; a reduction in the manufacturing time, said reduction leading to an enhancement in the productivity; and a remarkable reduction in the content of impurities such as sulfur in the reduced-iron agglomerates.

Abstract: A method for manufacturing granular metallic iron by reducing a raw material mixture including an iron oxide-containing material and a carbonaceous reducing agent, comprises: a step of charging the raw material mixture onto a hearth of a moving hearth-type thermal reduction furnace; a step of reducing the iron oxide in the raw material mixture by the carbonaceous reducing agent through the application of heat, thereby forming metallic iron, subsequently melting the metallic iron, and coalescing the molten metallic iron to granular metallic iron while separating the molten metallic iron from subgenerated slag; and a step of cooling the metallic iron to solidify; wherein the heat-reducing step includes a step of controlling the flow velocity of atmospheric gas in a predetermined zone of the furnace within a predetermined range. This method makes it possible to manufacture the granular metallic iron of high quality.

Abstract: A device for producing granular metal iron by placing a mass of a raw material mixture comprising a substance containing iron oxide and a carbonaceous reducing agent onto a heath of a moving heath type heating furnace and heating the mass to reduce iron oxide in the mass, thereby producing the granular metal iron. The device comprises, in addition to the moving heath type heating furnace, a sieving machine, a first magnetic separator and a second magnetic separator, and also comprises a passage through which a discharged substance from the moving heath type heating furnace is supplied to the sieving machine, a passage through which crude granules that have been sieved by the sieving machine are supplied to the first magnetic separator, and a passage through which fine granules that have been sieved by the sieving machine are supplied to the second magnetic separator.

Abstract: A method for manufacturing granular metallic iron by reducing a raw material mixture including an iron oxide-containing material and a carbonaceous reducing agent, comprises: a step of charging the raw material mixture onto a hearth of a moving hearth-type thermal reduction furnace; a step of reducing the iron oxide in the raw material mixture by the carbonaceous reducing agent through the application of heat, thereby forming metallic iron, subsequently melting the metallic iron, and coalescing the molten metallic iron to granular metallic iron while separating the molten metallic iron from subgenerated slag; and a step of cooling the metallic iron to solidify; wherein the heat-reducing step includes a step of controlling the flow velocity of atmospheric gas in a predetermined zone of the furnace within a predetermined range. This method makes it possible to manufacture the granular metallic iron of high quality.

Abstract: A method for manufacturing granular metallic iron by reducing a raw material mixture including an iron oxide-containing material and a carbonaceous reducing agent, comprises: a step of charging the raw material mixture onto a hearth of a moving hearth-type thermal reduction furnace; a step of reducing the iron oxide in the raw material mixture by the carbonaceous reducing agent through the application of heat, thereby forming metallic iron, subsequently melting the metallic iron, and coalescing the molten metallic iron to granular metallic iron while separating the molten metallic iron from subgenerated slag; and a step of cooling the metallic iron to solidify; wherein the heat-reducing step includes a step of controlling the flow velocity of atmospheric gas in a predetermined zone of the furnace within a predetermined range. This method makes it possible to manufacture the granular metallic iron of high quality.

Abstract: A feedstock-feeding step of feeding a feedstock containing a carbonaceous reductant and an iron oxide-containing material into a rotary hearth furnace, a heating/reducing step of heating the feedstock to reduce iron oxide contained in the feedstock into reduced iron, a melting step of melting the reduced iron, a cooling step of cooling the molten reduced iron, and a discharging step of discharging the cooled reduced iron are performed in that order in the direction that a hearth is moved. The furnace includes flow rate-controlling partitions, arranged therein, for controlling the flow of furnace gas and the furnace gas in the cooling step is allowed to flow in the direction of the movement of the hearth with the partitions.

Abstract: A method for producing granular iron comprising: charging agglomerates formed from a raw material mixture containing an iron oxide-containing substance and a carbonaceous reducing agent onto a carbonaceous material spread on a hearth of a furnace; and heating the agglomerates to thereby reduce and melt iron oxides in the agglomerates, wherein the temperature of the agglomerates in the furnace is set in a range between 1200° C. and 1500° C.; the oxygen partial pressure in atmospheric gas under which the agglomerates are heated is set to 2.0×10?13 atm or more at standard state; and the linear speed of the atmospheric gas in the furnace is set to 4.5 cm/second or more.

Abstract: It is an object of the present invention to provide a technique for solving the following problem by properly controlling the flow of gas such as air (oxidizing gas): a problem that the degree of reduction cannot be increased due to the air entering a feedstock-feeding zone or a discharging zone. The technique is a method for producing reduced iron. The method includes a feedstock-feeding step of feeding a feedstock containing a carbonaceous reductant and an iron oxide-containing material into a rotary hearth furnace, a heating/reducing step of heating the feedstock to reduce iron oxide contained in the feedstock into reduced iron, a melting step of melting the reduced iron, a cooling step of cooling the molten reduced iron, and a discharging step of discharging the cooled reduced iron, these steps being performed in that order in the direction that a hearth is moved.

Abstract: 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.

Abstract: A method for manufacturing granular metallic iron by reducing a raw material mixture including an iron oxide-containing material and a carbonaceous reducing agent, comprises: a step of charging the raw material mixture onto a hearth of a moving hearth-type thermal reduction furnace; a step of reducing the iron oxide in the raw material mixture by the carbonaceous reducing agent through the application of heat, thereby forming metallic iron, subsequently melting the metallic iron, and coalescing the molten metallic iron to granular metallic iron while separating the molten metallic iron from subgenerated slag; and a step of cooling the metallic iron to solidify; wherein the heat-reducing step includes a step of controlling the flow velocity of atmospheric gas in a predetermined zone of the furnace within a predetermined range. This method makes it possible to manufacture the granular metallic iron of high quality.

Abstract: A method for producing metallic iron in which a mixture including a carbonaceous reducing agent and iron oxide is fed onto a hearth of a moving hearth reducing-melting furnace and is then heated so that the iron oxide is reduced and melted. Metallic iron to be obtained is cooled and is then discharged outside the furnace for recovery. Prior to the feed of raw agglomerates, a granular hearth material is bedded on the moving hearth for forming a layered renewable hearth which can be renewed. Part or the entirety of the renewable hearth which was degraded during operation is renewed, and the hearth material for forming a new renewable hearth is fed. The surface of the newly formed hearth is then leveled and mixture is subsequently fed.

Abstract: 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.

Abstract: 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.

Abstract: A method for producing metallic iron in which a mixture including a carbonaceous reducing agent and iron oxide is fed onto a hearth of a moving hearth reducing-melting furnace and is then heated so that the iron oxide is reduced and melted. Metallic iron to be obtained is cooled and is then discharged outside the furnace for recovery. Prior to the feed of raw agglomerates, a granular hearth material is bedded on the moving hearth for forming a layered renewable hearth which can be renewed. Part or the entirety of the renewable hearth which was degraded during operation is renewed, and the hearth material for forming a new renewable hearth is fed. The surface of the newly formed hearth is then leveled and mixture is subsequently fed.