Proposed is a method for removing phosphorus from a phosphorus-containing substance which is applicable in an industrial scale so as to effectively reduce phosphorus contained in the phosphorus-containing substance. In this method, the phosphorus-containing substance used as a raw material for metal smelting or metal refining is reacted with a nitrogen-containing gas at a treatment temperature T (° C.) which is lower than a melting temperature (T.sub.m) of the substance, so that phosphorus is removed preferably in the form of phosphorus nitride (PN). In this regard, a nitrogen partial pressure and an oxygen partial pressure in the nitrogen-containing gas are preferably controlled, thereby reducing a load of dephosphorization process, for example.

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.

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.

Proposed is a method for removing phosphorus from a phosphorus-containing substance which is applicable in an industrial scale so as to effectively reduce phosphorus contained in the phosphorus-containing substance. In this method, the phosphorus-containing substance used as a raw material for metal smelting or metal refining is reacted with a nitrogen-containing gas at a treatment temperature T ( C.) which is lower than a melting temperature (T.sub.m) of the substance, so that phosphorus is removed preferably in the form of phosphorus nitride (PN). In this regard, a nitrogen partial pressure and an oxygen partial pressure in the nitrogen-containing gas are preferably controlled, thereby reducing a load of dephosphorization process, for example.

Provided is a smelting method in which, for example, a metal oxide such as a nickel oxide ore including nickel oxide is used as a source material and is reduced with a carbonaceous reducing agent to obtain a reduced product, with which method efficient processing can be achieved. This metal oxide smelting method is, for example, a nickel oxide ore smelting method. Specifically, the method includes a reduction process step S3 that has: a drying step S31 in which a mixture that was obtained by mixing a metal oxide and a carbonaceous reducing agent is dried; a preheating step S32 in which the dried mixture is preheated; a reduction step S33 in which the preheated mixture is reduced using a rotary hearth furnace 1, a hearth of which rotates; and a cooling step S35 in which the obtained reduced product is cooled.

Provided is a smelting method in which, for example, a metal oxide such as a nickel oxide ore including nickel oxide is used as a source material and is reduced with a carbonaceous reducing agent to obtain a reduced product, with which method efficient processing can be achieved. This metal oxide smelting method is, for example, a nickel oxide ore smelting method. Specifically, the method includes a reduction process step S3 that has: a drying step S31 in which a mixture that was obtained by mixing a metal oxide and a carbonaceous reducing agent is dried; a preheating step S32 in which the dried mixture is preheated; a reduction step S33 in which the preheated mixture is reduced using a rotary hearth furnace 1, a hearth of which rotates; and a cooling step S35 in which the obtained reduced product is cooled.

Provided is a smelting method in which, for example, a metal oxide such as a nickel oxide ore including nickel oxide is used as a source material and is reduced with a carbonaceous reducing agent to obtain a reduced product, with which method efficient processing can be achieved. This metal oxide smelting method is, for example, a nickel oxide ore smelting method. Specifically, the method includes a reduction process step that has: a drying step in which a mixture that was obtained by mixing a metal oxide and a carbonaceous reducing agent is dried; a preheating step in which the dried mixture is preheated; a reduction step in which the preheated mixture is reduced using a rotary hearth furnace, said rotary hearth having a hearth that rotates and not having a partition structure in an interior; and a cooling step in which the obtained reduced product is cooled.

A method for producing iron ore pellets for operation of a blast furnace, where the iron ore pellets have a CaO/SiO.sub.2 mass ratio greater than or equal to 0.8 and a MgO/SiO.sub.2 mass ratio greater than or equal to 0.4, the method including balling green pellets by adding water to an iron ore material and dolomite and firing the green pellets. The dolomite is in a miniaturized state in a structure of the green pellets.

The present disclosure provides a pre-reduced pellet preparation device and method based on grate-rotary kiln. The pre-reduced pellet preparation device comprises a grate-rotary kiln pellet oxidation system and a hydrogen-based shaft furnace reduction system. In the pre-reduced pellet preparation method, a roasting process and a reduction process for an iron-containing green pellet are organically combined, and a pellet cooling process after roasting and a heating process before pellet reduction are eliminated; physical heat of a roasted pellet is used to satisfy heat required in the heating and reduction processes; the technical problems of a low hydrogen utilization rate and high energy consumption of pellets in oxidative roasting and direct reduction processes in traditional direct reduction processes are solved; a reduced pellet having a certain metallization rate is obtained; the prepared pre-reduced pellet is used as blast furnace burden, such that blast furnace fuel consumption and carbon emission can be significantly reduced; the method is a new, low-carbon, and green pre-reduced pellet preparation process.

The present disclosure provides a pre-reduced pellet preparation device and method based on grate-rotary kiln. The pre-reduced pellet preparation device comprises a grate-rotary kiln pellet oxidation system and a hydrogen-based shaft furnace reduction system. In the pre-reduced pellet preparation method, a roasting process and a reduction process for an iron-containing green pellet are organically combined, and a pellet cooling process after roasting and a heating process before pellet reduction are eliminated; physical heat of a roasted pellet is used to satisfy heat required in the heating and reduction processes; the technical problems of a low hydrogen utilization rate and high energy consumption of pellets in oxidative roasting and direct reduction processes in traditional direct reduction processes are solved; a reduced pellet having a certain metallization rate is obtained; the prepared pre-reduced pellet is used as blast furnace burden, such that blast furnace fuel consumption and carbon emission can be significantly reduced; the method is a new, low-carbon, and green pre-reduced pellet preparation process.