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Method for producing reduced iron compact in rotary hearth reducing furnace, reduced iron compact, and method for producing pig iron using the same

A kind of technology of rotary hearth and manufacturing method, applied in the field of manufacturing pig iron and reduced iron forming body

Inactive Publication Date: 2004-12-15
NIPPON STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0021] The prior art has no effective means to solve this problem, and cannot carry out efficient reduction treatment to prevent pulverization

Method used

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  • Method for producing reduced iron compact in rotary hearth reducing furnace, reduced iron compact, and method for producing pig iron using the same
  • Method for producing reduced iron compact in rotary hearth reducing furnace, reduced iron compact, and method for producing pig iron using the same
  • Method for producing reduced iron compact in rotary hearth reducing furnace, reduced iron compact, and method for producing pig iron using the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0109] figure 1 The result of working using the rotary hearth type reduction furnace shown is shown. This facility is for manufacturing reduced iron pellets for blast furnaces at a rate of 15 tons per hour.

[0110] The raw material powder is a powder mixed with finely powdered iron ore (pellet raw material), converter gas dust, and fine coke. The total iron ratio is 54% by mass, the carbon ratio is 14% by mass, and the atomic molar ratio of carbon and active oxygen is is 1.05. This was manufactured into a molded body with a porosity of 23% by a molding device (pan granulator) 8 . The average particle size is 13mm (volume 1150mm 3). It was dried to a moisture content of 1% by mass, heated in a heating zone in a rotary hearth type reduction furnace 11, and then fired and reduced for 10 minutes at an average gas temperature of 1370° C. in the reducing zone. The number of laying layers of the molded body was 1.4. The reduced iron pellets obtained here were cooled with a rot...

Embodiment 2-5

[0115] Illustrate adopting the method of the present invention, basically use Figure 7 The equipment of carrying out the operation result of the rotary hearth type reduction furnace of embodiment 2-5. Table 1 shows the results of the operation of restoring molded bodies molded by the three molding methods using the present invention. Example 2 is an operation example of reducing a molded body having a porosity of 24% with a ratio of ferric oxide of 55% by mass using a pan granulator. Example 3 is an operation example in which a molded body having a porosity of 30% produced by a block molding machine containing 63% by mass of ferric oxide was reduced. In addition, Example 4 is an operation example of reducing a cylindrical molded body with a porosity of 43% produced by an extrusion molding machine containing 82% by mass of ferric oxide. Also, in Example 5, the converter dust with an average particle diameter of 2.9 μm containing 75% by mass of ferric oxide and containing met...

Embodiment 2

[0117] In Example 2, the porosity is higher than the appropriate porosity V1 value calculated from the ratio of ferrous oxide: 18%. As a result, the pulverization rate of the molded body during reduction was 6.9%, and the average metal ratio of the reduced iron molded body and the powdered reduced product was also as high as 83%. In Example 3, the porosity is higher than the appropriate porosity V1 value calculated from the ratio of ferrous oxide: 23%. As a result, the pulverization rate of the molded body during reduction was 5.8%, and the average metal ratio of the reduced iron molded body and the powdered reduced product was also as high as 85%. In addition, the porosity of the molded body of Example 4 was very high at 43%, and even if the ratio of ferric oxide was 82% by mass and the appropriate porosity V1 value was 33%, the pulverization of the molded body was very little, Just 3.3%. Moreover, the metallization rate of the molded article was also very good at 87%.

[...

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Abstract

There is provided a method of producing reduced iron compacts with high crushing strength, low powderization and a high reduction rate in a solid reduction-type firing reducing furnace such as a rotary hearth-type reducing furnace, as well as reduced iron compacts obtained by the method and a method of melt-reducing the reduced iron compacts in a blast furnace. In the method of producing reduced iron compacts, the atomic molar ratio of carbon to oxygen chemically combined with iron, manganese, nickel, zinc and lead, in raw material powder comprising a mixture of iron oxide-containing powder and carbon-containing powder, or the ferric oxide content of the raw material powder, is in a specified range, the compact is produced so as to give a porosity in a given range, and the compact is put on the hearth of a reducing furnace equipped with a rotating hearth and is heated for heating reduction by the heat from the combustion gas in the upper part of the furnace, for firing reduction at above a prescribed temperature.

Description

technical field [0001] The present invention relates to a method for producing a high-strength reduced iron compact by heating and reducing a molded body made of powder containing iron oxide in a rotary hearth type reduction furnace, and the reduced iron molded body obtained by the method. In addition, it relates to a method for producing pig iron using the molded body of the reduced iron in a blast furnace for ironmaking. [0002] In the present invention, the so-called molded body includes powders containing iron oxide formed into pellets, blocks and other massive, spherical or granular materials, and the so-called reduced iron molded body includes firing and reducing the above-mentioned iron oxide-containing moldings in a reduction furnace. body of matter. Background technique [0003] There are various processes for producing reduced iron and alloy iron, but the process of reducing in a solid state using carbon as a reducing agent is practiced in various countries becau...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B1/16C21B13/00C21B13/02C21B13/10
CPCC21B13/105C21B13/023C21B13/0046C21B13/10
Inventor 茨城哲治井村章次织田博史高桥政治安部洋一高桥茂树铃木聪
Owner NIPPON STEEL CORP
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