This method is for producing granular metallic iron in which the relation between the mass ratio (mass %) of the volatile matter content contained in a carbonaceous reducing agent and the average gas flow rate (m/s) of the ambient gas in a heating furnace fulfills expression (1). Mass ratio of volatile matter content4.62average gas flow rate+46.7 . . . (1)

Provided is a raw material particle for production of agglomerate that can be used to produce an agglomerate with better reducing performance than conventional agglomerates. The raw material particle 1(2) of the present disclosure is a raw material particle for producing an agglomerate as a raw material for producing reduced iron, including a central part 11(21), and a peripheral part 12(22) that covers the periphery of the central part 11(21). The central part 11 has a metal iron-containing substance, the central part 12 has a volatile substance, and the peripheral part 12(22) has iron oxide.

A hearth for a traveling hearth furnace for the production of pig iron grade nuggets, the hearth having a synthetic graphite material in direct contact with the process charge in producing a plurality of metallic iron nodules and slag. The process charge including iron containing oxide, a predetermined amount of a reductant and flux, which are carried into and through a reducing, melting and coalescing stages on the hearth, wherein resulting metallic iron nodules and slag are in direct contact with the synthetic graphite material and do not adhere to the synthetic graphite material of the hearth. The absence adherence and ease of removal minimizes any impurities in the pig iron grade nuggets and allows the hearth to be used more than one cycle without the need for any replenishment of the contact surface.

A rotary hearth furnace includes a unit that supplies an agglomerate onto a hearth of the rotary hearth furnace, a unit that discharges a heated substance which has been heated in the rotary hearth furnace to the outside of the furnace, and a unit that discharges an exhaust gas in the rotary hearth furnace to the outside of the furnace. The rotary hearth furnace has a heating section and a non-heating section. The unit that discharges an exhaust gas to the outside of the furnace is provided in the non-heating section. A unit that takes an outside air into the furnace is provided in the non-heating section and on an upstream side in a flow direction of the exhaust gas from the unit that discharges exhaust gas to the outside of the furnace.

Provided is a smelting method for producing metal by reducing a mixture that includes an oxide ore such as nickel oxide ore, wherein it is possible to improve productivity by raising the metal recovery rate as well as to inexpensively and efficiently produce high-quality metal. The present invention is a smelting method in which: an oxide ore and a carbonaceous reducing agent are mixed; the resulting mixture is heated and subjected to a reduction treatment; and metal and slag, which are reduction products, are obtained, wherein the reduction treatment is carried out in a state in which one or more surface deposits selected from carbonaceous reducing agents, metal oxides, and oxidation inhibitors are deposited on the surface of the mixture.

The present invention addresses the problem, in methods for producing a metal or alloy by reducing a mixture that contains an oxide ore, of providing an oxide ore smelting method with good productivity and efficiency. The present invention is an oxide ore smelting method for producing a metal or alloy by reducing a mixture that contains an oxide ore, the method comprising at least: a mixing step S1 for mixing an oxide ore with a carbonaceous reducing agent; a mixture-molding step S2 for molding the mixture obtained to obtain a mixture-molded body; and a reducing step S3 for heating the mixture-molded body obtained at a specified reducing temperature in a reducing furnace.

To provide a method for producing agglomerated ore, with which reduced iron can be efficiently produced by hydrogen reduction, without the need for preheating raw material and raising the temperature of reducing gas. A method for producing agglomerated ore, the method including sintering a sintering raw material containing an iron-containing raw material and a condensation material in a sintering machine to form a sinter cake, and obtaining agglomerated ore by crushing the sinter cake, in which iron oxide contained in the sinter cake is reduced by distributing a reducing gas through the sinter cake on the sintering machine, to make a degree of reduction of iron oxide contained in the agglomerated ore after crushing 50% or more.

An improved direct smelting system and process using a smelt reduction vessel (SRV), and optionally, a cyclone converter furnace (CCF). The improved system and process utilizes a fast quench system in which hot process offgas containing molten material is quench-cooled from greater than 1400? C. (2552? F.) to no more than 600? C. (1112? F.) in a time-of-flight of no greater than 1 second. The quenching occurs using water spray injection and vaporization to cool, stress and break solid slag into slag pieces small enough to remove from the quenching system. The improved system eliminates plant availability problems associated with (i) accretion formation in the offgas train as hot process offgas cools down in a conventional (slow) manner to allow for steam-raising for power generation or other heat recovery purposes, and (ii) trigger mechanisms causing slag foaming events in the SRV that propagate up the offgas train.

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.

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:

C.sub.fix?X.sub.under105/O.sub.FeO?51(I)

where O.sub.FeO is the mass percentage of oxygen contained in the iron oxide in the agglomerate, C.sub.fix is the mass percentage of total fixed carbon contained in the agglomerate, and X.sub.under105 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.