Process for producing reduced iron powder

A technology for reducing iron powder and production technology, which is applied in the direction of fluidized bed furnace, etc., can solve the problems of slow reduction speed, large waste heat value, and low production efficiency, and achieve the effect of fast reduction speed, short time consumption and high production efficiency

Active Publication Date: 2012-08-22
LAIWU IRON & STEEL GRP
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] (1) Low production efficiency and unstable quality
In the canning process, the reducing agent and the iron concentrate are packed in different containers, and the primary reduction is mainly realized by indirect reduction. relatively poor stability
Moreover, the primary reduction process is generally completed in a tunnel kiln, and the kiln car needs to be pushed into or pulled out of the tunnel kiln by external force, so the kiln car cannot be made too large, and the capacity of the tunnel kiln is limited
[0005] (2) Low utilization rate of heat energy
The temperature of the high-temperature section of the tunnel kiln for the production of sponge iron is generally above 1150°C, and the waste heat generated by the entire furnace system is very large. Except for a small part

Method used

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  • Process for producing reduced iron powder
  • Process for producing reduced iron powder

Examples

Experimental program
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Effect test

Example Embodiment

[0032] Example 1:

[0033] High-purity iron powder, coke powder and organic binder with a TFe content of 73.2% were used for mixing at a mass ratio of 80.9:16.3:2.8, and the moisture content of the mixture was controlled at about 9%. Balls; raw balls are dried by hot air in a chain grate dryer at 300° C. for 15 minutes to remove the water content to less than 3%; then put into a rotary hearth furnace for reduction, and through five-stage reduction (the highest reduction temperature of 1250° C.) for 30 minutes, the obtained Sponge iron with a TFe content of more than 95%; after the sponge iron is crushed, magnetically separated, and screened, the -200um primary powder is fed into a steel belt reduction furnace, and reduced at 920 ° C in an ammonia decomposition atmosphere for 40-60 minutes to obtain a powder cake; The powder cake is crushed, sieved and batched to obtain high-quality reduced iron powder with particle size -150um≥95, TFe≥98.5%, and hydrogen loss≤0.25%.

Example Embodiment

[0034] Example 2:

[0035] Using TFe content of 73.2% high-purity iron powder, coal powder, and organic binder to mix at a mass ratio of 80.9:16.3:2.8, the moisture content of the mixture is controlled at about 8%, and a high-pressure briquetting machine is used to obtain 20×30×40mm The briquette; the briquette is dried with hot air at 250°C for 20min in a chain grate dryer, and the moisture is removed to less than 3%; then sent to the rotary hearth furnace for reduction, and the five-stage reduction (the highest reduction temperature is 1320°C) for 28min , to obtain sponge iron with a TFe content of more than 95%; after the sponge iron is crushed, magnetically separated, and screened, the primary powder of -200um is fed into a steel belt reduction furnace, and reduced at 920 ° C under an ammonia decomposition atmosphere for 50-70min. Powder cake; crush, sieve and batch the powder cake to obtain high-quality reduced iron powder with particle size -150um≥95, TFe≥98.5%, and hydr...

Example Embodiment

[0036] Example 3:

[0037] Using TFe content of 73.5% rolled iron and steel, phosphorus, coal powder, and organic binder to mix at a mass ratio of 81.0:16.2:2.8, the water content of the mixture is controlled at about 9%, and a disc pelletizing machine is used to obtain Φ25mm-Φ35mm raw materials. Balls; raw balls are dried with hot air at 260°C for 18min in a chain grate dryer, and the water content is removed to less than 3%; then it is reduced in a rotary hearth furnace, and is reduced in five stages (the highest reduction temperature is 1320°C) for 28 minutes to obtain Sponge iron with a TFe content of more than 95%; after the sponge iron is crushed, magnetically separated, and screened, the -200um primary powder is fed into a steel belt reduction furnace, and reduced at 920 ° C under an ammonia decomposition atmosphere for 50-60 minutes to obtain a powder cake; The powder cake is crushed, sieved and batched to obtain high-quality reduced iron powder with particle size -150...

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Abstract

An efficiency energy-saving process for producing reduced iron powder is implemented through the technical scheme as follows: firstly, the process comprises the following steps of: 1) dosing high-purity iron concentrate fines/mill scales, a reducing agent and an adhesive according to certain proportions, mixing all the materials together and subjecting the mixture to wet grinding treatment, and forming the ground mixture into green balls through pelletizing/pressing into ball; 2) after the green balls are screened and dried, putting the green balls in a rotary hearth furnace for primary reduction, thereby obtaining sponge iron, wherein as the iron core powder is in direct contact with the reducing agent, the reducing speed is high, the time consumed is short and the production efficiency is high; and the high temperature smoke at 1000-1100 DEG C of the rotary hearth furnace enters a smoke waste heat recovery system, thereby realizing efficiency utilization of heat energy; and 3) after performing crashing, magnetic selection and screening on the sponge iron, performing secondary reduction in a steel strip type reducing furnace, and performing crashing, screening and blending on the obtained powder cake, thereby obtaining the reduced iron powder; and 4) the process for producing the reduced iron powder effectively solves the problems of low reduced iron powder productivity, poor quality stability, low heat utilization ratio, high working intensity, bad working environment and the like.

Description

technical field [0001] The invention relates to a high-efficiency and energy-saving production process of reduced iron powder, which belongs to the technical field of powder metallurgy production. Background technique [0002] The production process of reduced iron powder in the powder metallurgy industry is generally: (iron concentrate, rolled steel scale, etc.) → drying → magnetic separation → crushing → screening → canning → primary reduction → sponge iron → cleaning → crushing → magnetic separation →Secondary reduction→powder block→decompression→magnetic separation→sieving→grading→mixing→packaging→finished product. [0003] There are the following drawbacks to this commonly used process: [0004] (1) Low production efficiency and unstable quality. In the canning process, the reducing agent and the iron concentrate are packed in different containers, and the primary reduction is mainly realized by indirect reduction. The stability is relatively poor. Moreover, the pri...

Claims

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Application Information

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IPC IPC(8): B22F9/20C21B13/00
Inventor 曾晖李建云杜春峰周林罗霞光周小辉
Owner LAIWU IRON & STEEL GRP
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