Abstract: A method for manufacturing a reduced metal includes thermally reducing a metal oxide including a carbonaceous reductant disposed on a hearth moving in a reducing furnace, wherein the reducing furnace includes a plurality of primary burners for supplying fuel and primary combustion air, and a plurality of secondary combustion burners for supplying secondary combustion air; and wherein the primary combustion air and/or the secondary combustion air is oxygen-enriched air, the oxygen concentration in the primary combustion air supplied from at least one of the plurality of primary burners being controlled to be lower than the oxygen concentration in the secondary combustion air.

Abstract: PROBLEM TO BE SOLVED: 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: 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 system provides assistance in the delivery of industrial wastes from industrial waste-generating sites to one or more industrial waste treatment sites based on exchanged information on industrial wastes containing metal oxide. The system includes a server, terminals at the industrial waste-generating sites, and terminals at the industrial waste treatment sites. Each terminal at the industrial waste-generating site transmits the information on industrial wastes to the server. The server stores the transmitted formation into an information storage unit. The server receives the search conditions from one of the industrial waste treatment sites who require industrial wastes, search the information storage unit, and transmits the search result to the terminal at the corresponding industrial waste treatment site. The terminal at the industrial waste treatment site displays the search result.

Abstract: The present invention provides a process that is useful in producing ferronickel having a high Ni content at low cost with high efficiency and reproducibility even if a low-grade feedstock containing nickel oxide is used. In particular, a feedstock containing nickel oxide and iron oxide is mixed with a carbonaceous reductant, the mixture is formed into agglomerates with an agglomerator, and the agglomerates are heated and reduced in a moving hearth furnace, whereby reduced agglomerates in which the Ni metallization degree is 40% or more and the Fe metallization degree is at least 15% less than the Ni metallization degree are prepared by adjusting the retention time of the agglomerates placed in the moving hearth furnace. The reduced agglomerates, in which the Ni component has been primarily reduced as compared with the Fe component, are smelted in a smelting furnace, whereby ferronickel having a high Ni content is obtained.

Abstract: A method of producing stainless steel includes the steps of melting a raw material in an electric furnace to form molten steel, and then refining the molten steel by a refining furnace to produce stainless steel in a stainless steel producing process. In the method, a carbonaceous reducing agent is added to a zinc-containing waste material produced in the stainless steel producing process, the resultant mixture is agglomerated by a briquette press to form agglomerates incorporated with a carbonaceous material, the agglomerates incorporated with the carbonaceous material are heated in a rotary hearth furnace to reduce and evaporate zinc to form dezincified agglomerates, and then the dezincified agglomerates are charged as a coolant in an oxidation period of the refining furnace.

Abstract: The prevent invention provides a method for producing a feed material for molten metal production and a method for producing a molten metal capable of sufficiently carbonizing biomass and effectively using carbonized biomass as a reducing agent. In the method for producing a feed material for molten metal production, a mixture containing an iron oxide-containing material and biomass is heated in a heating furnace substantially isolated from oxygen to carbonize the biomass in the mixture and obtain a feed material for molten metal production, or the mixture is charged in a reducing furnace to reduce the iron oxide-containing material after being heated in the heating furnace. In the method for producing a molten metal, the feed material for molten metal production obtained by the method for producing a feed material for molten metal production is charged in a melting furnace to obtain a molten metal.

Abstract: A method of producing stainless steel includes the steps of melting a raw material in an electric furnace to form molten steel, and then refining the molten steel by a refining furnace to produce stainless steel in a stainless steel producing process. In the method, a carbonaceous reducing agent is added to a zinc-containing waste material produced in the stainless steel producing process, the resultant mixture is agglomerated by a briquette press to form agglomerates incorporated with a carbonaceous material, the agglomerates incorporated with the carbonaceous material are heated in a rotary hearth furnace to reduce and evaporate zinc to form dezincified agglomerates, and then the dezincified agglomerates are charged as a coolant in an oxidation period of the refining furnace.

Abstract: A method of producing stainless steel includes the steps of melting a raw material in an electric furnace to form molten steel, and then refining the molten steel by a refining furnace to produce stainless steel in a stainless steel producing process. In the method, a carbonaceous reducing agent is added to a zinc-containing waste material produced in the stainless steel producing process, the resultant mixture is agglomerated by a briquette press to form agglomerates incorporated with a carbonaceous material, the agglomerates incorporated with the carbonaceous material are heated in a rotary hearth furnace to reduce and evaporate zinc to form dezincified agglomerates, and then the dezincified agglomerates are charged as a coolant in an oxidation period of the refining furnace.

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 13.6° 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: The present invention can provide a method for combustion treatment capable of efficiently treating combustible waste, and a combustion treatment apparatus capable of realizing such a method. The present invention can further provide a method for combustion treatment capable of efficiently treating even combustible waste containing a generation source of a volatile hazardous component, and a combustion treatment apparatus capable of realizing this. Furthermore, the present invention can provide a method for combustion treatment capable of efficiently recovering and making effective use of the heat of an exhaust gas discharged during a treatment of combustible waste, and a combustion treatment apparatus capable of realizing this. The aforementioned method for combustion treatment is a method for treating combustible waste, in which the combustible waste is subjected to combustion treatment in a rotary hearth furnace.

Abstract: The present invention provides a process that is useful in producing ferronickel having a high Ni content at low cost with high efficiency and reproducibility even if a low-grade feedstock containing nickel oxide is used. In particular, a feedstock containing nickel oxide and iron oxide is mixed with a carbonaceous reductant, the mixture is formed into agglomerates with an agglomerator, and the agglomerates are heated and reduced in a moving hearth furnace, whereby reduced agglomerates in which the Ni metallization degree is 40% or more and the Fe metallization degree is at least 15% less than the Ni metallization degree are prepared by adjusting the retention time of the agglomerates placed in the moving hearth furnace. The reduced agglomerates, in which the Ni component has been primarily reduced as compared with the Fe component, are smelted in a smelting furnace, whereby ferronickel having a high Ni content is obtained.

Abstract: A method for making reduced iron using blast-furnace sludge is provided. The method includes a mixing step of mixing the blast-furnace sludge and an iron-oxide-containing powder to prepare a mixed material, an agglomerating step of agglomerating the mixed material to form agglomerates, a feeding step of feeding the agglomerates onto a continuously moving hearth, and a reducing step of heating the agglomerates to remove zinc and reduce the agglomerates.

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 method of producing reduced metals is disclosed in which a mixture of a metal oxide and a reducing agent is heated by a burner such that the metal oxide is reduced to a reduced metal. Dry-distilled gas generated during carbonization of an organic matter-containing component is used as fuel for the burner. The sensible heat of exhaust gas evolved by the burner is utilized as heat for carbonizing the organic matter-containing component. Carbide derived by carbonizing the organic matter-containing component is used as the above reducing agent. This method yields excellent cost performance. An apparatus for reducing metal oxides is also disclosed.

Abstract: A method for manufacturing a reduced metal includes thermally reducing a metal oxide including a carbonaceous reductant disposed on a hearth moving in a reducing furnace, wherein the reducing furnace includes a plurality of primary burners for supplying fuel and primary combustion air, and a plurality of secondary combustion burners for supplying secondary combustion air; and wherein the primary combustion air and/or the secondary combustion air is oxygen-enriched air, the oxygen concentration in the primary combustion air supplied from at least one of the plurality of primary burners being controlled to be lower than the oxygen concentration in the secondary combustion air.

Abstract: The prevent invention provides a method for producing a feed material for molten metal production and a method for producing a molten metal capable of sufficiently carbonizing biomass and effectively using carbonized biomass as a reducing agent. In the method for producing a feed material for molten metal production, a mixture containing an iron oxide-containing material and biomass is heated in a heating furnace substantially isolated from oxygen to carbonize the biomass in the mixture and obtain a feed material for molten metal production, or the mixture is charged in a reducing furnace to reduce the iron oxide-containing material after being heated in the heating furnace. In the method for producing a molten metal, the feed material for molten metal production obtained by the method for producing a feed material for molten metal production is charged in a melting furnace to obtain a molten metal.

Abstract: A method for operating manufacturing equipment including a heating furnace is provided. The method comprises the step of spraying a blowdown water that has been in the manufacturing equipment into effluent gas discharged from the heating furnace so as to vaporize the blowdown water and remove solid dust contained in the effluent gas. In a plant implementing this method, the amount of the effluent water can be reduced to substantially zero, no purification equipment is required, and solid sludge which has been produced in the purification equipment is thus completely reduced. Moreover, in this method, iron and zinc can be recycled as fly ash which can be easily treated and recycled.

Abstract: A method of producing stainless steel includes the steps of melting a raw material in an electric furnace to form molten steel, and then refining the molten steel by a refining furnace to produce stainless steel in a stainless steel producing process. In the method, a carbonaceous reducing agent is added to a zinc-containing waste material produced in the stainless steel producing process, the resultant mixture is agglomerated by a briquette press to form agglomerates incorporated with a carbonaceous material, the agglomerates incorporated with the carbonaceous material are heated in a rotary hearth furnace to reduce and evaporate zinc to form dezincified agglomerates, and then the dezincified agglomerates are charged as a coolant in an oxidation period of the refining furnace.

Abstract: The present invention provides a method of purifying polluted soil and/or burned ash containing heavy metals and/or organic compounds with a higher throughput than a conventional method. In this method, polluted soil and/or burned ash is dried by, for example, a rotary dryer so that the moisture content is 5% by mass or less, preferably 3% by mass or less, and then large lumps having a particle diameter of 10 mm or more are removed by a vibrating screen. Only an undersize portion is formed into a briquette having a volume of about 6 cm3 by a press molding machine. The briquette is charged in a rotary hearth furnace together with the large lumps, and heated in the furnace to remove or detoxify the heavy metals and organic compounds by evaporation with high efficiency.