Raw material for direct reduction, method of producing raw material for direct reduction, and method of producing reduced iron

Abstract

A raw material for direct reduction which is reduced in a shaft furnace includes a raw material, and a coating layer which coats the raw material and has a porosity of 20 volume % or more.

1 . A raw material for direct reduction which is reduced in a shaft furnace, comprising:
 a raw material; and   a coating layer which coats the raw material and has a porosity of 20 volume % or more.   
     
     
         2 . The raw material for direct reduction according to  claim 1 ,
 wherein the coating layer includes at least one of an oxide of Ca and an oxide of Mg.   
     
     
         3 . A method of producing a raw material for direct reduction which is reduced in a shaft furnace, the method comprising:
 coating a raw material with a slurry containing at least one of calcium hydroxide, magnesium hydroxide, and cement hydrate;   evaporating moisture included in the coated raw material using gas not including CO 2  before charging the coated raw material into the shaft furnace; and   dehydrating combined water included in the coated raw material at a dehydration temperature or higher using gas not including H 2 O steam.   
     
     
         4 . The method of producing a raw material for direct reduction according to  claim 3 , wherein
 in the coating, the raw material is coated with the slurry using an immersion method or a spraying method.   
     
     
         5 . A method of producing a reduced iron, the method comprising:
 charging the coated raw material produced by the method according to  claim 3  or  4  into the shaft furnace at a temperature higher than room temperature,   wherein the shaft furnace is a reduction furnace for producing reduced iron using reduction gas including hydrogen.   
     
     
         6 . The method of producing a reduced iron according to  claim 5 , further comprising:
 preheating the coated raw material to the temperature higher than room temperature before charging the coated raw material into the shaft furnace.