Abstract: Provided is a method for manufacturing iron nuggets by which reduced iron obtained by heating and reducing agglomerates, or iron nuggets obtained by melting and aggregating the reduced iron can be prevented from reoxidation inside a movable hearth heating furnace and quality of the reduced iron can be improved. The method involves charging and heating agglomerates including iron oxide and a carbonaceous reducing agent on a hearth of a movable hearth heating furnace, reducing and melting the iron oxide in the agglomerates, and then discharging obtained iron nuggets to the outside of the furnace and recovering the iron nuggets. The agglomerates have a coating layer, including a fluid carbonaceous material, on the surface.

Abstract: The present invention is directed to provide a production method for carbonaceous material-containing metal oxide briquettes, capable of ensuring sufficient strength of briquettes while using a metal oxide material containing a large amount of fine particles, such as steel mill dust. This method comprises a mixing step of mixing a metal oxide material A containing a large amount of fine particles with a carbonaceous material B in a mixer 15, to form a powdery mixture E, a compacting step of compacting the powdery mixture E using a briquette machine 17 to form compacts F, a classifying step of classifying the compacts F into an oversize fraction G and an undersize fraction H, using a sieve 18, and collecting the oversize fraction G as product briquettes, and a compact circulating step of returning a part of the compacts F to the mixer 15 or the briquette machine 17, as a recycle material.

Abstract: An iron melting furnace has a refractory lined furnace body having a top opening through which raw materials including a raw material iron source, a carbonaceous material and a slag forming material may be introduced. A heating system is provided for injecting oxygen-containing gas into the furnace body to combust the carbonaceous material, whereby combustion heat can melt the raw material iron source to generate molten iron and molten slag to form a molten iron and slag bath. A plurality of tap holes penetrate the furnace body and are provided at positions different from one another in a height direction of the furnace body, and a refractory filling which is different from the refractory liner material fills at least one of the tap holes such that molten iron or slag in the furnace is unable to flow through the tap hole being filled with the refractory material.

Abstract: A method for producing molten iron by melting an iron source material using an iron bath-type melting furnace comprising a top-blowing lance at an upper part of the furnace, a bottom-blowing tuyere in the bottom of the furnace and a tap hole at a lower part on the side of the furnace, the method comprising: a melting process of melting the iron source material, wherein the melting process has at least one tapping process of discharging the molten iron and the slag through the tap hole while holding a position of the furnace in generating the molten iron, and the tapping process continues or interrupts generation of the molten iron and continues top-blowing of the oxygen-containing gas to thereby keep a temperature of the molten iron in the furnace at or above a pre-set lowest temperature of the molten iron.

Abstract: An object of the present invention is to provide a method for reducing a chromium-containing material at a high chromium reduction degree. In the method of the present invention, a mixture of a feedstock containing chromium oxide and a carbonaceous reductant is heated and reduced by radiation heating in a moving hearth furnace. The average rate of raising the temperature of the mixture in the reduction is preferably 13.96° C./s or higher in the period from the initiation of the radiation heating of the mixture until the mixture reaches 1,114° C.

Abstract: A method for producing carbon composite metal oxide briquettes includes a mixing step of adding a binder to a metal oxide raw material and a carbonaceous material and mixing the metal oxide raw material, the carbonaceous material, and the binder by a mixer to prepare a powder mixture, and a forming step of forming the powder mixture into carbon composite metal oxide briquettes by using a briquetting machine, in which, in the mixing step, a batch mixer is used as the mixer.

Abstract: The method includes the steps of: adding a carbonaceous material B and a binder C, and optionally water, to electric furnace dust A generated in a steelmaking electric furnace 1, to form a powdery mixture D having a water content of 0.5 to 3 mass %; compacting the powdery mixture D into a raw briquette E; and charging the raw briquette without drying into a rotary hearth furnace 5 and thermally reducing the raw briquette to obtain a reduced iron briquette F and a crude zinc oxide G.

Abstract: The present invention provides a method for efficiently manufacturing a titanium oxide-containing slag from a material including titanium oxide and iron oxide, wherein a reduction of titanium dioxide is suppressed and the electric power consumption is minimized. The method includes the steps of: heating a raw material mixture including titanium oxide, iron oxide, and a carbonaceous reductant, or the raw material mixture further including a calcium oxide source, in a reducing furnace; reducing the iron oxide in the mixture to form reduced iron; feeding the resultant mixture to a heating melting furnace; heating the resultant mixture in the heating melting furnace to melt the reduced iron and separate the reduced iron from a titanium oxide-containing slag; and discharging and recovering the titanium oxide-containing slag out of the furnace.

Abstract: A process for producing molten iron is a process in which while an inert gas is blown into a molten iron layer in an iron bath type melting furnace through bottom-blown tuyeres provided in a hearth bottom thereof to stir the molten iron layer, a carbon material, an additive flux, and solid reduced iron obtained by heating reduction of carbon composite iron oxide briquettes are charged into the above melting furnace, and top blowing of an oxygen-containing gas is performed through a top-blown lance provided for the melting furnace, so that the solid reduced iron is melted by combustion heat obtained by combusting the carbon material and/or carbon in molten iron to form molten iron.

Abstract: A method for manufacturing molten iron comprises charging a carbonaceous material, a flux, and solid reduced iron obtained by thermally reducing carbon composite iron oxide agglomerates into an arc melting furnace and melting the solid reduced iron using arc heating in the melting furnace while an inert gas is blown into a molten iron layer from a bottom blowing tuyere on a bottom of the melting furnace, wherein: a carbonaceous material suspending slag layer is formed in an upper portion of a slag layer formed on the molten iron layer when the solid reduced iron is melted into the molten iron; a carbonaceous material coating layer having the carbonaceous material is formed on the carbonaceous material suspending slag layer; and the molten iron and the slag stored in the melting furnace are tapped from a tap hole formed in a lower portion of a furnace wall of the melting furnace.

Abstract: Disclosed is an iron bath-type melting furnace characterized by comprising a furnace body and a plurality of tap holes provided at different positions of the furnace body in the direction of the height thereof so as to extend through the furnace body, and in that an iron source as a raw material together with a carbon material and a slag-making material is charged into the furnace and further an oxygen-containing gas is injected into the furnace to melt the iron source as the raw material by combustion heat generated by combustion of the carbon material and/or carbon contained in the molten iron and to produce molten iron and molten slag are produced, and the plurality of the tap holes is used while switching from the uppermost tap hole toward downward tap holes to tap the iron slag being conducted, whereby molten iron is produced by intermittently taking out the molten iron and the molten slag to the outside of the furnace while maintaining the furnace body erect.

Abstract: 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.

Abstract: A method for producing molten iron by melting an iron source material using an iron bath-type melting furnace comprising a top-blowing lance at an upper part of the furnace, a bottom-blowing tuyere in the bottom of the furnace and a tap hole at a lower part on the side of the furnace, the method comprising: a melting process of charging the iron source material, a carbonaceous material and a flux into the furnace and top-blowing an oxygen-containing gas through the top-blowing lance while blowing an inert gas through the bottom-blowing tuyere into melt present in the furnace to stir the melt to thereby melt the iron source material and generate the molten iron and slag using combustion heat of combusting carbon in the carbonaceous material and/or in the molten iron, wherein the melting process has at least one tapping process of discharging the molten iron and the slag through the tap hole while holding a position of the furnace in generating the molten iron, and the tapping process continues or interrupts ge

Abstract: A process for producing molten iron is a process in which while an inert gas is blown into a molten iron layer in an iron bath type melting furnace through bottom-blown tuyeres provided in a hearth bottom thereof to stir the molten iron layer, a carbon material, an additive flux, and solid reduced iron obtained by heating reduction of carbon composite iron oxide briquettes are charged into the above melting furnace, and top blowing of an oxygen-containing gas is performed through a top-blown lance provided for the melting furnace, so that the solid reduced iron is melted by combustion heat obtained by combusting the carbon material and/or carbon in molten iron to form molten iron.

Abstract: It is an object of the present invention to provide a method of compacting a powdery mixture of electric furnace dust and a carbonaceous material into a briquette and subjecting the briquette to a thermal reduction treatment in a rotary hearth furnace, the method being capable of ensuring a strength of the briquette resistant to a handling in a course after the compacting through until it is set in the rotary hearth furnace, and reducing energy necessary for drying of the briquette while preventing bursting thereof in the rotary hearth furnace. The method comprises the steps of: adding a carbonaceous material B and a binder C, and optionally water, to electric furnace dust A generated in a steelmaking electric furnace 1, to form a powdery mixture D having a water content of 0.

Abstract: Provided are an exhaust gas processing system and method capable of effectively utilizing the sensible heat of an exhaust gas for preheating air for burner combustion in a rotary hearth type reducing furnace while preventing troubles caused by adhesion of dust such as blockage in an exhaust gas processing facility for a rotary hearth type reducing furnace and corrosive deterioration in the facility without increasing the facility costs excessively. The system comprises a radiant heat exchanger 2 for heat exchange between an exhaust gas exhausted from the rotary hearth type reducing furnace and air.

Abstract: A method for producing carbon composite metal oxide briquettes includes a mixing step of adding a binder to a metal oxide raw material and a carbonaceous material and mixing the metal oxide raw material, the carbonaceous material, and the binder by a mixer to prepare a powder mixture, and a forming step of forming the powder mixture into carbon composite metal oxide briquettes by using a briquetting machine, in which, in the mixing step, a batch mixer is used as the mixer.

Abstract: A method for manufacturing molten iron includes a step of charging a carbonaceous material, a flux, and solid reduced iron obtained by thermally reducing carbon composite iron oxide agglomerates into an arc melting furnace and melting the solid reduced iron using arc heating in the melting furnace while an inert gas is blown into a molten iron layer contained in the melting furnace from a bottom blowing tuyere disposed on a bottom of the melting furnace to stir the molten iron layer, wherein the carbonaceous material is charged so that a carbonaceous material suspending slag layer in which the carbonaceous material is suspended is formed in an upper portion of a slag layer formed on the molten iron layer by slag produced when the solid reduced iron is melted into the molten iron and so that a carbonaceous material coating layer composed of only the carbonaceous material is further formed on the carbonaceous material suspending slag layer, and the molten iron and the slag stored in the melting furnace are tapp

Abstract: The present invention is directed to provide a production method for carbonaceous material-containing metal oxide briquettes, capable of ensuring sufficient strength of briquettes while using a metal oxide material containing a large amount of fine particles, such as steel mill dust. This method comprises a mixing step of mixing a metal oxide material A containing a large amount of fine particles with a carbonaceous material B in a mixer 15, to form a powdery mixture E, a compacting step of compacting the powdery mixture E using a briquette machine 17 to form compacts F, a classifying step of classifying the compacts F into an oversize fraction G and an undersize fraction H, using a sieve 18, and collecting the oversize fraction G as product briquettes, and a compact circulating step of returning a part of the compacts F to the mixer 15 or the briquette machine 17, as a recycle material.

Abstract: An object of the present invention is to provide a method for reducing a chromium-containing material at a high chromium reduction degree. In the method of the present invention, a mixture of a feedstock containing chromium oxide and a carbonaceous reductant is heated and reduced by radiation heating in a moving hearth furnace. The average rate of raising the temperature of the mixture in the reduction is preferably 13.96° C./s or higher in the period from the initiation of the radiation heating of the mixture until the mixture reaches 1,114° C.