A rotary hearth furnace includes: a furnace body which surrounds a ring-like space; a hearth portion which forms a bottom portion of the ring-like space and is rotatable in the rotational direction; a gas exhaust portion which discharges an exhaust gas generated in the ring-like space to the outside of the furnace body; an introducing portion; and a flow rate regulating portion. The introducing portion is disposed upstream of the gas exhaust portion in the rotational direction and introduces a pressure regulating gas into a non-heating section of the ring-like space. The flow rate regulating portion is disposed between the introducing portion and the gas exhaust portion and regulates a flow rate of a gas by adjusting an opening area of the non-heating section.

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)

A smelting method capable of obtaining an iron-nickel alloy having a high nickel grade of 4% or higher by effectively facilitating a reduction reaction of pellets formed using a nickel oxide ore as a raw material. The present invention is a method for smelting a nickel oxide ore, by which an iron-nickel alloy is obtained by forming pellets from a nickel oxide ore and reducing and heating the pellets. In the pellet production step S1, a mixture is obtained by mixing raw materials that contain at least a nickel oxide ore and a carbonaceous reducing agent. In the reduction step S2, a furnace floor carbonaceous reducing agent is laid on the floor of the smelting furnace in advance when placing the obtained pellets in the smelting furnace and the pellets are placed on the furnace floor carbonaceous reducing agent and then reduced and heated.

A smelting method capable of obtaining an iron-nickel alloy having a high nickel grade of 4% or higher by effectively facilitating a reduction reaction of pellets formed using a nickel oxide ore as a raw material. The present invention is a method for smelting a nickel oxide ore, by which an iron-nickel alloy is obtained by forming pellets from a nickel oxide ore and reducing and heating the pellets. In the pellet production step S1, a mixture is obtained by mixing raw materials that contain at least a nickel oxide ore and a carbonaceous reducing agent. In the reduction step S2, a furnace floor carbonaceous reducing agent is laid on the floor of the smelting furnace in advance when placing the obtained pellets in the smelting furnace and the pellets are placed on the furnace floor carbonaceous reducing agent and then reduced and heated.

Smelting metalliferous feed material process forming molten metal in smelting apparatus including smelt cyclone above and communicating with smelting vessel to contain molten metal and slag bath, including: partially reducing and melting feed material in smelt cyclone, allowing the molten partially reduced feed material flow downwardly into vessel, supplying oxygen-containing gas and carbonaceous material to vessel, smelting molten partially reduced feed material in molten metal and slag bath in vessel forming molten metal discharged from vessel and reaction products projected upwardly from molten bath, at least partially combusting combustible materials in reaction products in vessel space above molten bath, supplying oxygen-containing gas to smelt cyclone. Further combusting reaction products in smelt cyclone, discharging from smelt cyclone offgas including reaction products, supplying oxygen-containing gas into offgas duct upstream high temperature section combusting remaining offgas combustible materials while sufficiently hot for safe ignition and avoiding downstream burner-managed incineration.

Smelting metalliferous feed material process forming molten metal in smelting apparatus including smelt cyclone above and communicating with smelting vessel to contain molten metal and slag bath, including: partially reducing and melting feed material in smelt cyclone, allowing the molten partially reduced feed material flow downwardly into vessel, supplying oxygen-containing gas and carbonaceous material to vessel, smelting molten partially reduced feed material in molten metal and slag bath in vessel forming molten metal discharged from vessel and reaction products projected upwardly from molten bath, at least partially combusting combustible materials in reaction products in vessel space above molten bath, supplying oxygen-containing gas to smelt cyclone. Further combusting reaction products in smelt cyclone, discharging from smelt cyclone offgas including reaction products, supplying oxygen-containing gas into offgas duct upstream high temperature section combusting remaining offgas combustible materials while sufficiently hot for safe ignition and avoiding downstream burner-managed incineration.

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 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.

Provided is a smelting method whereby a reaction for reducing pellets, said pellet being formed by using a saprolite ore as a starting material, can be effectively conducted and thus an iron/nickel alloy having a nickel grade of, for example, 16% or greater can be obtained. The method comprises: a pellet production step (S1) for producing the pellets from the saprolite ore; and a reduction step (S2) for heating and reducing the obtained pellets in a smelting furnace. In the pellet production step (S1), at least the saprolite ore and a preset amount of a carbonaceous reducing agent are mixed together to produce the pellets. In the reduction step (S2), a hearth carbonaceous reducing agent is preliminarily spread on the hearth of the smelting furnace and the pellets produced above are placed on the hearth carbonaceous reducing agent and then subjected to a heat reduction treatment.

Provided is a smelting method whereby a reaction for reducing pellets, said pellet being formed by using a saprolite ore as a starting material, can be effectively conducted and thus an iron/nickel alloy having a nickel grade of, for example, 16% or greater can be obtained. The method comprises: a pellet production step (S1) for producing the pellets from the saprolite ore; and a reduction step (S2) for heating and reducing the obtained pellets in a smelting furnace. In the pellet production step (S1), at least the saprolite ore and a preset amount of a carbonaceous reducing agent are mixed together to produce the pellets. In the reduction step (S2), a hearth carbonaceous reducing agent is preliminarily spread on the hearth of the smelting furnace and the pellets produced above are placed on the hearth carbonaceous reducing agent and then subjected to a heat reduction treatment.