Abstract: A method for producing granular metallic iron of the present invention includes: an agglomeration step of obtaining agglomerates through agglomeration of a mixture that contains an iron oxide-containing material and a carbonaceous reducing agent; and a granulation step of obtaining granular metallic iron by heating the agglomerates, reducing iron oxides in the agglomerates, aggregating generated metallic iron to be granular while separating the metallic iron from slag generated as a by-product, and thereafter cooling and solidifying the metallic iron, wherein agglomerates satisfying all the conditions given by formulas (1) to (3) below are used as the agglomerates: (1) [(total CaO amount+total SiO2 amount+total Al2O3 amount)/total Fe amount]?0.250; (2) (total CaO amount/total SiO2 amount)?0.9; (3) [total Al2O3 amount/(total CaO amount+total SiO2 amount+total Al2O3 amount)]×100?9.7.

Abstract: Provided is a process for manufacturing reduced iron by heating agglomerates, said process being capable of enhancing the yield of reduced iron and thus improving the productivity thereof. A process for manufacturing reduced iron which includes a step for agglomerating a mixture that comprises an iron oxide source, a carbonaceous reducing agent and a melting point regulator and a step for heating the obtained agglomerates to reduce the iron oxide contained in the agglomerates, wherein the agglomerates contain at least 1 mass % of a silicate mineral having a solidus temperature of 1300° C. or lower.

Abstract: A system of coal gasification and direct ironmaking attains both heat recovery in a coal-based direct ironmaking process and a reduction in equipment investment in a coal gasification process. A waste heat boiler in the system recovers heat of gas exhausted from a coal gasification furnace. A heater in exhaust gas lines of a heat reduction furnace in the coal-based direct ironmaking process superheats the steam generated by and exhausted from the waste heat boiler. A superheated steam line supplies the steam superheated by the heater as an oxidant to the coal gasification furnace.

Abstract: A system of coal gasification and direct ironmaking attains both heat recovery in a coal-based direct ironmaking process and a reduction in equipment investment in a coal gasification process. A waste heat boiler in the system recovers heat of gas exhausted from a coal gasification furnace. A heater in exhaust gas lines of a heat reduction furnace in the coal-based direct ironmaking process superheats the steam generated by and exhausted from the waste heat boiler. A superheated steam line supplies the steam superheated by the heater as an oxidant to the coal gasification 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 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: Provided is a rotary hearth furnace which can stir exhaust gas within a furnace, to efficiently burn flammable gas within the exhaust gas and to efficiently heat an object to be heated, and which can contribute to reduction of specific energy consumption and improvement of productivity. A rotary hearth furnace (1) has therein a series of zone spaces (3) which are divided by vertical walls (2) hanging from a ceiling (1c). Among the zone spaces (3), the zone space to which an exhaust gas duct (4) is attached is constructed as an exhaust zone (3a). An oxygen-containing gas supply unit (5) is provided in the vicinity of the lower edge of the vertical wall (2) which divides the exhaust zone (3a) from the other zone spaces (3). Further, the exhaust gas duct (4) is disposed on the outer periphery side or the inner periphery side from the center of the width of the zone space (3).

Abstract: A method of suppressing slag foaming that can grasp a state of slag foaming in the continuous melting furnace and accurately suppress the slag foaming so as to enable continuous production of molten metal in a stable state. This method includes charging of a suppressor into slag in the furnace, measuring a flow rate of a flue gas discharged from the continuous melting furnace during blowing of the slag over time, increasing a charging speed rate of the suppressor if the flue gas flow rate has an increasing tendency and decreasing the charging speed rate of the suppressor if the flue gas flow rate has a decreasing tendency.

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 of suppressing slag foaming that can grasp a state of slag foaming in the continuous melting furnace and accurately suppress the slag foaming so as to enable continuous production of molten metal in a stable state. This method includes charging of a suppressor into slag in the furnace, measuring a flow rate of a flue gas discharged from the continuous melting furnace during blowing of the slag over time, increasing a charging speed rate of the suppressor if the flue gas flow rate has an increasing tendency and decreasing the charging speed rate of the suppressor if the flue gas flow rate has a decreasing tendency.

Abstract: A system of coal gasification and direct ironmaking which is effective in attaining both heat recovery in a coal-based direct ironmaking process and a reduction in equipment investment in a coal gasification process. The system is characterized by being equipped with: a waste heat boiler (16) for recovering heat of gas exhausted from a coal gasification furnace; a heater (7) provided in exhaust gas lines (1a and 1b) of a heat reduction furnace (1) in the coal-based direct ironmaking process and superheating the steam generated by and exhausted from the waste heat boiler (16); and a superheated steam line (23) for supplying the steam superheated by the heater (7) as an oxidant to the coal gasification furnace (10).

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: 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: 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: To effectively separate and recover solid dust and volatile or molten components while preventing solid dust and volatile or molten component dust from being adhered to inner walls of a temperature control tower.

Abstract: In a temperature control device comprising a temperature control tower for controlling a blown high-temperature exhaust gas to a proper temperature and discharging the temperature-controlled exhaust gas to the subsequent step side, the temperature control tower comprises a cooling water spray means for spraying cooling water to about the center of the gas flow of the high-temperature exhaust gas and a cooling gas injecting means for injecting cooling gas along the inner wall of the temperature control tower.

Abstract: An apparatus for producing a reduced metal includes a moving hearth reducing furnace, a feeding section, a metal discharge section, a gas discharge section, and a regenerative burner. The moving hearth reducing furnace heats a raw material composed of a metal oxide component and a carbonaceous reducing component to form the reduced metal. The feeding section feeds the raw material into the moving hearth reducing furnace. The metal discharge section discharges the reduced metal from the moving hearth reducing furnace. The gas discharge section discharges waste gas from the furnace and is disposed in a reducing process between the moving hearth reducing furnace and the metal discharge section. The regenerative burner functions as a heat source for the moving hearth reducing furnace.

Abstract: To effectively separate and recover solid dust and volatile or molten components while preventing solid dust and volatile or molten component dust from being adhered to inner walls of a temperature control tower.

Abstract: A moving hearth is formed by providing a layer of hearth material primarily composed of iron oxide on a base refractory in a reducing furnace and then sintering the hearth material so that the sintered moving hearth is not melted at an operational temperature in a reducing step. The moving hearth is more easily constructed compared to providing a shaped or amorphous refractory on the base refractory, has high durability, and can maintain surface flatness during operation.

Abstract: A moving hearth reducing furnace is operated, while a gap is provided between a discharging apparatus for discharging reduced iron agglomerates from the moving hearth reducing furnace and the surface of the moving hearth. The gap prevents squeezing metallic iron powder formed by reduction of powder included in iron oxide agglomerates into the surface of the moving hearth and the formation of an iron sheet. An iron oxide layer formed on the moving hearth during the operation can be periodically scraped off without shutdown of the furnace.