Method and system for producing direct reduced metal material, comprising the steps: a) charging metal material to be reduced into a furnace space (120); b) evacuating an existing atmosphere from the furnace space to achieve a gas pressure of less than 1 bar therein, c) providing heat and hydrogen gas into the furnace space, so that heated hydrogen gas heats the charged metal material to a temperature high enough so that metal oxides present in the metal material are reduced, in turn causing water vapour to be formed, which hydrogen gas provision is performed so that a pressure of more than 1 bar builds up inside the furnace space; and d) before evacuating the built up overpressure, condensing and collecting the water vapour formed in step c in a condenser (160) below the charged metal material. The invention is characterised in that it further comprises the step e) before evacuating the build up overpressure, providing a carbon-containing gas to the furnace space, so that the heated and reduced metal material is carburized by said carbon-containing gas.

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.

Provided is a smelting method capable of effectively promoting a reduction reaction on pellets formed using nickel oxide ore as starting material to obtain a ferronickel alloy with a high nickel grade of at least 4%. The present invention is a method for smelting nickel oxide ore wherein ferronickel alloy with a nickel grade of at least 4%, the method comprising a pellet-producing step S1 for producing pellets from nickel oxide ore, and a reducing step S2 for reduction-heating of the obtained pellets in a smelting furnace. In the pellet-producing step S1, the pellets are produced by mixing nickel oxide ore with a specified amount of a carbonaceous reducing agent as starting materials. In the reducing step S2, the produced pellets are charged in a smelting furnace in which a carbonaceous reducing agent (furnace bottom carbonaceous reducing agent) has been spread over the entire furnace bottom and reduction-heating is performed.

Provided is a smelting method capable of effectively promoting a reduction reaction on pellets formed using nickel oxide ore as starting material to obtain a ferronickel alloy with a high nickel grade of at least 4%. The present invention is a method for smelting nickel oxide ore wherein ferronickel alloy with a nickel grade of at least 4%, the method comprising a pellet-producing step S1 for producing pellets from nickel oxide ore, and a reducing step S2 for reduction-heating of the obtained pellets in a smelting furnace. In the pellet-producing step S1, the pellets are produced by mixing nickel oxide ore with a specified amount of a carbonaceous reducing agent as starting materials. In the reducing step S2, the produced pellets are charged in a smelting furnace in which a carbonaceous reducing agent (furnace bottom carbonaceous reducing agent) has been spread over the entire furnace bottom and reduction-heating is performed.

The present invention relates to a method and apparatus for producing reduced iron from ironmaking dust which contains iron oxide which is generated at an ironmaking plant, takes note of the rotary kiln reduction method which does not require pretreatment of the dust, and has as its problem the pursuit of facilities which achieve further improvement of heat efficiency and stable operation.

To solve this problem, the present invention is characterized by heating and reducing carbon-containing shaped materials in a single closed space in which an internal heat type rotary kiln and an external heat type rotary kiln are arranged in series and including at least the insides of the two rotary kilns during which making the reduced exhaust gas which is generated at the external heat type rotary kiln burn inside of the internal heat type rotary kiln.

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.

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.

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.

A method of starting a molten bath-based process for smelting a metalliferous material is disclosed. The method includes using the heat flux of water-cooled elements in lower parts of a smelting vessel to provide an indication of molten bath temperature during at least an early part of the start-up method and adjusting injection rates of oxygen-containing gas and/or carbonaceous material into the smelting vessel to control the molten bath temperature during start-up without exceeding critical heat flux levels and tripping the start-up method.