Raw material particles for production of agglomerate, method for producing raw material particles for production of agglomerate, agglomerate, method for producing agglomerate, and method for producing reduced iron

Abstract

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.

1 . A raw material particle for production of agglomerate, which is a raw material particle for producing an agglomerate as a raw material for producing reduced iron, comprising
 a central part, and a peripheral part that covers a periphery of the central part, wherein   the central part has a metal iron-containing substance or a volatile substance, and the peripheral part has iron oxide.   
     
     
         2 . The raw material particle for production of agglomerate according to  claim 1 , wherein the iron oxide contains at least either or both of more than 4 mass % of water of crystallization and more than 1.5 mass % of alumina. 
     
     
         3 . The raw material particle for production of agglomerate according to  claim 1 , wherein the central part has a particle size of 2 mm or more and 6 mm or less. 
     
     
         4 . The raw material particle for production of agglomerate according to  claim 1 , wherein the peripheral part has a thickness of 2 mm or more and 5 mm or less. 
     
     
         5 . A method for producing a raw material particle for production of agglomerate, which is a method for producing the raw material particle according to  claim 1 , comprising
 a pretreatment process of grinding a raw material containing the iron oxide into raw material powder, and then classifying the raw material powder to adjust a particle size of the raw material powder, and   a process of mixing and granulating the raw material powder whose particle size has been adjusted, the metal iron-containing substance or the volatile substance, and a binder to obtain the raw material particle.   
     
     
         6 . The method for producing a raw material particle for production of agglomerate according to  claim 5 , wherein the metal iron-containing substance or the volatile substance with a particle size of 2 mm or more and 6 mm or less is used in the granulation process. 
     
     
         7 . The method for producing a raw material particle for production of agglomerate according to  claim 5 , wherein a thickness of the peripheral part is adjusted to 2 mm or more and 5 mm or less in the granulation process. 
     
     
         8 . An agglomerate obtained by baking or sintering and agglomerating the raw material particle according to  claim 1 , wherein
 for the agglomerated raw material particle,   when the central part before baking or sintering has the metal iron-containing substance, the agglomerated raw material particle has a three-layer structure, where the central part has a first portion having the metal iron-containing substance and a second portion that covers a periphery of the first portion, and metal iron contained in the metal iron-containing substance is oxidized in the second portion, and   when the central part before baking or sintering has the volatile substance, the agglomerated raw material particle has a hollow structure where the central part is a void.   
     
     
         9 . A method for producing an agglomerate, comprising baking or sintering and agglomerating the raw material particle according to  claim 1  in an oxidizing atmosphere of 1200° ° C. or higher and 1350° C. or lower to obtain an agglomerate. 
     
     
         10 . A method for producing reduced iron, comprising charging the agglomerate according to  claim 8  into a reducing furnace while introducing a reducing gas into the reducing furnace, and reducing iron oxide contained in the agglomerate by the reducing gas to obtain reduced iron. 
     
     
         11 . The method for producing reduced iron according to  claim 10 , wherein a gas containing hydrogen as a main component is used as the reducing gas. 
     
     
         12 . The raw material particle for production of agglomerate according to  claim 2 , wherein the central part has a particle size of 2 mm or more and 6 mm or less. 
     
     
         13 . A method for producing a raw material particle for production of agglomerate, which is a method for producing the raw material particle according to  claim 2 , comprising
 a pretreatment process of grinding a raw material containing the iron oxide into raw material powder, and then classifying the raw material powder to adjust a particle size of the raw material powder, and   a process of mixing and granulating the raw material powder whose particle size has been adjusted, the metal iron-containing substance or the volatile substance, and a binder to obtain the raw material particle.   
     
     
         14 . A method for producing a raw material particle for production of agglomerate, which is a method for producing the raw material particle according to  claim 3 , comprising
 a pretreatment process of grinding a raw material containing the iron oxide into raw material powder, and then classifying the raw material powder to adjust a particle size of the raw material powder, and   a process of mixing and granulating the raw material powder whose particle size has been adjusted, the metal iron-containing substance or the volatile substance, and a binder to obtain the raw material particle.   
     
     
         15 . A method for producing a raw material particle for production of agglomerate, which is a method for producing the raw material particle according to  claim 4 , comprising
 a pretreatment process of grinding a raw material containing the iron oxide into raw material powder, and then classifying the raw material powder to adjust a particle size of the raw material powder, and   a process of mixing and granulating the raw material powder whose particle size has been adjusted, the metal iron-containing substance or the volatile substance, and a binder to obtain the raw material particle.   
     
     
         16 . A method for producing a raw material particle for production of agglomerate, which is a method for producing the raw material particle according to  claim 12 , comprising
 a pretreatment process of grinding a raw material containing the iron oxide into raw material powder, and then classifying the raw material powder to adjust a particle size of the raw material powder, and   a process of mixing and granulating the raw material powder whose particle size has been adjusted, the metal iron-containing substance or the volatile substance, and a binder to obtain the raw material particle.   
     
     
         17 . An agglomerate obtained by baking or sintering and agglomerating the raw material particle according to  claim 2 , wherein
 for the agglomerated raw material particle,   when the central part before baking or sintering has the metal iron-containing substance, the agglomerated raw material particle has a three-layer structure, where the central part has a first portion having the metal iron-containing substance and a second portion that covers a periphery of the first portion, and metal iron contained in the metal iron-containing substance is oxidized in the second portion, and   when the central part before baking or sintering has the volatile substance, the agglomerated raw material particle has a hollow structure where the central part is a void.   
     
     
         18 . An agglomerate obtained by baking or sintering and agglomerating the raw material particle according to  claim 3 , wherein
 for the agglomerated raw material particle,   when the central part before baking or sintering has the metal iron-containing substance, the agglomerated raw material particle has a three-layer structure, where the central part has a first portion having the metal iron-containing substance and a second portion that covers a periphery of the first portion, and metal iron contained in the metal iron-containing substance is oxidized in the second portion, and   when the central part before baking or sintering has the volatile substance, the agglomerated raw material particle has a hollow structure where the central part is a void.   
     
     
         19 . An agglomerate obtained by baking or sintering and agglomerating the raw material particle according to  claim 12 , wherein
 for the agglomerated raw material particle,   when the central part before baking or sintering has the metal iron-containing substance, the agglomerated raw material particle has a three-layer structure, where the central part has a first portion having the metal iron-containing substance and a second portion that covers a periphery of the first portion, and metal iron contained in the metal iron-containing substance is oxidized in the second portion, and   when the central part before baking or sintering has the volatile substance, the agglomerated raw material particle has a hollow structure where the central part is a void.   
     
     
         20 . A method for producing an agglomerate, comprising baking or sintering and agglomerating a raw material particle obtainable by the method for producing a raw material particle for production of agglomerate according to  claim 5  in an oxidizing atmosphere of 1200° C. or higher and 1350° C. or lower to obtain an agglomerate.