IP Library Granted Patent US 11,198,914
Granted Patent B2
US 11,198,914 · App. 16/834,510 · Granted Dec 14, 2021

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

Inventors: Moritoshi Mizutani (Kimitsu, JP); Tsunehisa Nishimura (Sodegaura, JP)
Assignee: NIPPON STEEL CORPORATION
C21B13/02C21B13/0046C22B1/16Y02P10/134
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Quick Facts
Patent No.
US 11,198,914
App. No.
16/834,510
Granted
Dec 14, 2021
Kind
B2
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.

Claims (10)

1. A method of producing a material for direct reduction which is reduced in a shaft furnace, the method comprising:

coating a processed product by immersing the processed product in a slurry containing one or more of calcium hydroxide, magnesium hydroxide, and cement hydrate, the processed product comprising one or more of an iron ore lump, a sinter, a pellet, and a briquette;

evaporating moisture included in the coated processed product, by heating the coated processed product in an evaporation furnace, wherein an atmosphere in the evaporation furnace does not include CO 2 , before charging the coated processed product into the shaft furnace; and

after moisture is removed from the coated processed product, dehydrating combined water included in the coated processed product by heating in a dehydration furnace at a dehydration temperature or higher, using gas not including H 2 O steam,

wherein a coating layer, formed on said material for direct reduction after said coating, evaporating and dehydrating, has a porosity of 20 volume % or more.

2. A method of producing a reduced iron, the method comprising:

charging the material for direct reduction produced by the method according to claim 1 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.

3. The method of producing a reduced iron according to claim 2 , further comprising:

preheating the material for direct reduction to the temperature higher than room temperature before charging the material for direct reduction into the shaft furnace.