JPH1017905A - Production of iron powder form steel making furnace dust - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing iron powder from steel making furnace dust capable of inexpensively producing a large amt. of high-purity refined iron powder having the decreased variations in the purity by continuously treating the dust generated in a steel making furnace. SOLUTION: This process has a washing stage for washing the raw material dust by the water ejected from the upper part of a spiral body 28 while gradually ejecting the raw material dust charged into a water settling vessel 26 by a water precipitate ejecting means 27 and an eluate washing stage for subjecting the washed iron powder to a pickling treatment by the acid liquid of the hydrochloric acid, sulfuric acid, etc., ejected from the upper part of the spiral body 34 while gradually ejecting the washed iron powder charged into an acid settling vessel 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reducing agent used for regenerating iron powder for fusing, iron powder for powder metallurgy, or etching waste liquid purified from dust generated during steelmaking blowing in a pure oxygen blowing converter or the like. The present invention relates to a method for producing iron powder from steelmaking furnace dust for obtaining iron powder or the like as a material.

[0002]

2. Description of the Related Art Dust collected from a pure oxygen blowing converter and the like contains coarse particles mainly composed of metallic iron generated in the middle stage of blowing, in which decarburization reaction is intense, and FeO generated in the latter stage of blowing. , Fe ₃
And fine powder mainly composed of O _{4 and the} like. These are collectively collected and treated as they are as low value-added raw materials such as blast furnace sinter or pellets. Conventionally, it has been attempted to increase the added value by collecting metallic iron in such dust and removing impurities such as scale and slag, and to use it in applications such as fusing iron powder and powder metallurgy iron powder. Have been. For example, Japanese Patent Publication No. 57-4
Japanese Patent No. 4724 discloses that dust generated in a pure oxygen blowing steelmaking converter is recovered by a wet method, and the dust is classified into -44.
a first step of reducing the particles having a size of 30 μm or less, a second step of separating the coarse dust from impurities such as scale and slag by a wet pulverizer, and removing impurities from the separated dust. A method for extracting iron powder by a third step of obtaining metallic iron and a fourth step of purifying the metallic iron is described.

[0003]

However, in the method described in Japanese Patent Publication No. Sho 57-44724, the third step of obtaining metallic iron by removing impurities from dust involves general classification and thin stream separation. Alternatively, since magnetic separation is performed, there is a problem that the dust processing capacity is low and the removal efficiency is low, so that large-scale processing is difficult. In addition, since the fourth step of refining metallic iron is performed by a combination of iron oxide refining or purification treatment by dilute acid leaching, continuous treatment is difficult, and crushing treatment or washing treatment in a subsequent step is difficult. There is a problem that it becomes complicated and that a large quantity of purified iron powder of stable quality cannot be obtained.

[0004] The present invention has been made in view of such circumstances, and continuously processes dust generated in a steelmaking furnace.
An object of the present invention is to provide a method for producing iron powder from steelmaking furnace dust, which is capable of producing high-purity refined iron powder in large quantities and at low cost with little variation in purity.

[0005]

According to the present invention, there is provided a semiconductor device comprising:
The method for producing iron powder from steelmaking furnace dust according to the description is to collect the raw material dust by a wet method from dust iron powder containing impurities such as CaO generated from the steelmaking furnace, and to use the pulverizer such as a ball mill or a vibro mill for the raw material dust. Wet pulverization step of pulverizing, and a water washing step of washing the wet pulverized material generated in the step with water and removing the impurities together with fine powder to obtain a cleaning iron powder; and pickling the cleaning iron powder to remove the impurities remaining. Eluting and removing the iron powder from the steelmaking furnace dust having an elution washing step of removing the water, wherein the water washing step is carried out by a water sediment carrying-out means having a helically driven and spirally disposed spiral. A step of washing the raw material dust carried out by the water jetted from the upper part of the spiral while gradually discharging the raw material dust put into the precipitation tank; In the step, the washing iron powder put into the acid solution precipitation tank is ejected from the upper portion of the spiral while gradually discharging the washing iron powder put into the acid solution precipitation tank by the acid solution precipitate carrying means having a spiral body which is arranged and rotated and inclined. And pickling the washed iron powder carried out with an acid solution such as hydrochloric acid or sulfuric acid to obtain purified iron powder from which CaO is removed as much as possible from the acid solution precipitate discharging means. The method for producing iron powder from steelmaking furnace dust according to claim 2 is the method for producing iron powder from steelmaking furnace dust according to claim 1, wherein the CaO concentration of the purified iron powder is less than 0.1 wt%. The method for producing iron powder from steelmaking furnace dust according to claim 3 is the method for producing iron powder from steelmaking furnace dust according to claim 1 or 2, wherein the acid solution has a hydrogen ion concentration (pH) of 0.5 to 3.0. 0 sulfuric acid or hydrochloric acid solution. The method for producing iron powder from steelmaking furnace dust according to claim 4 is the method for producing iron powder from steelmaking furnace dust according to claim 2 or 3, wherein the acid solution is sulfuric acid and the amount of sulfuric acid used is purified iron. 10-400 liters per ton of flour.

The concentration of CaO in the purified iron powder is 0.1 wt.
%, CaO is concentrated in the solution when the purified iron powder is repeatedly used for regenerating the etching waste liquid, and scale is generated to cause nozzle clogging or decrease the etching ability. It is not preferable. The second reason is as follows. In the etching waste liquid treatment, the amount of the liquid after the etching waste liquid treatment is increased to about 1.5 times that before the treatment in order to keep the iron concentration in the regenerating liquid constant. Then, in order to treat the excess etching waste liquid, the waste liquid is blown into a furnace in an oxidizing atmosphere maintained at 650 ° C. to 660 ° C.
An operation of converting iron chloride in a waste liquid into iron oxide, chlorine gas, hydrogen chloride and the like to recover hydrochloric acid and iron oxide has been performed. Therefore, when the CaO concentration of the recovered iron oxide is high, the iron oxide cannot be used for ferrite or the like, and in that sense, it is necessary to reduce the CaO concentration to an allowable value or less.

The acid solution has a hydrogen ion concentration (pH) of 0.1.
If it is smaller than 5, the acid solution becomes highly corrosive, and it is necessary to apply a special acid-resistant treatment to the equipment, which increases the equipment maintenance cost. On the other hand, if the hydrogen ion concentration is higher than 3.0, impurities including scale, slag, and the like that adhere to the iron powder cannot be sufficiently eluted, which is not preferable. On the other hand, if the amount of the sulfuric acid used as the acid solution is less than 10 liters per ton of purified iron powder, impurities are eluted and removed, so that purified iron powder of required purity cannot be obtained. Conversely, even if the amount of sulfuric acid used is more than 400 liters,
The amount of impurities eluted cannot be substantially increased, and further acid treatment is not necessary, and the cost of wastewater treatment in a subsequent step increases.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. FIG. 1 is an explanatory view showing a part of a steelmaking facility 10 to which a method for producing iron powder from steelmaking furnace dust according to an embodiment of the present invention is applied. As shown in FIG. 1, a steelmaking facility 10 includes a converter 11, which is an example of a steelmaking furnace, a hood section 12 disposed at an upper portion of the converter 11 for collecting dust iron powder and generated gas, and a hood section. An exhaust system 13 connected to the exhaust system 12, a chimney 14 for exhausting the exhaust system 13,
A wet classifier 19 for extracting raw material dust from dust iron powder collected in the exhaust system 13, and dust iron powder collected by injection water blown into the second injection port 16 in the exhaust system 13 And a thickener 18 for supplying blast water to be blown into the second injection port 16.

The wet classifier 19 includes a dust sedimentation tank 20 for storing dust collected by water injected from the first injection port 15 in the exhaust system 13 and a rotating spiral body 22 inside the pipe. A sediment carrying-out means 21 for performing a classification process by winding up the sediment in the tank 20 and raising the sediment in the tube is provided. In such a wet classifier 19, by supplying washing water or the like from the open upper part of the sediment discharge means 21, the fine powder portion in the sediment is selectively formed along the inner wall of the sediment discharge means 21. Descending and flowing out, the particle size in the sediment is relatively large,
The dust sediment from which excess water has been removed is discharged from the upper end of the sediment discharge means 21 so that the sediment can be classified or washed. First injection port 1 of exhaust system 13
5 and the vicinity of the second injection port 16 have a throttle structure. By blowing water into the orifice portion, the exhaust gas or dust iron powder and the water are mixed effectively, and trapped by the water. Dust iron powder is the first injection port 15
And, it is configured to be discharged from a discharge port provided on the downstream side of the second injection port 16.

[0010] The dust precipitate is treated in a wet grinding process of grinding and grinding in a wet state using a grinding machine such as a ball mill or a vibro mill to obtain raw material dust (wet ground material).
Becomes FIG. 2 is a configuration diagram of a hydroxyl cleaning apparatus 23 for performing water cleaning and acid cleaning of the obtained raw material dust.
As shown in FIG.
And an acid cleaning device 30. And the water washing device 2
4 is a water sedimentation tank 26 into which the raw material dust is charged, and the water sedimentation layer 26 for treating the sediment of the water sedimentation layer 26.
An acid precipitating tank 32 into which the washing iron powder discharged from the upper part of the water sediment discharging means 27 is charged.
And an acid-liquid-precipitate discharge means 33 for scooping up the precipitate in the acid-precipitation tank 32 to perform washing, classification, and water removal.
And

The lower part of the water sediment discharge means 27 and the acid liquid sediment discharge means 33 is immersed in the water sedimentation tank 26 and the acid sedimentation tank 32, respectively, and has an angle of 10 to 15 degrees with respect to the horizontal direction. And each of the unloading means 27, 33
At least the upper part is open in a half-split structure.
Then, the water sediment discharging means 27, the acid liquid sediment discharging means 3
3 are provided with spiral bodies 28 and 34 for scraping up and moving up the sediment deposited in each of the sedimentation tanks 26 and 32. The spiral bodies 28 and 34 are rotated by rotating a motor (not shown) or the like. The sediment caught in the gap between the spirals 28 and 34 and the unloading means 27 and 33 moves up along the unloading means 27 and 33.
Further, a water supply pipe 25 and an acid solution supply pipe 31 are arranged above the carry-out means 27 and 33, respectively, and supply the cleaning water or the acid solution to the open portions of the upper parts of the carry-out means 27 and 33. it can. Therefore, the sediment rising and moving in each of the unloading means 27 and 33 and the washing water or the acid solution flowing down by gravity in each of the unloading means 27 and 33 are effectively stirred,
At the same time, the particles having a relatively small particle size in the sediment are washed away and descend in the respective discharge means 27, 33 to accumulate in the respective sedimentation tanks 26, 32. The paper is discharged from the upper part of each of the carrying-out means 27 and 33.

Next, a method for producing iron powder from steelmaking furnace dust according to one embodiment of the present invention using the above-described steelmaking equipment 10 and the hydroxylic acid washing apparatus 23 will be described with reference to the flow chart of iron powder production shown in FIG. Description will be made based on the drawings. First, raw material dust containing water discharged from the wet classifier 19 of FIG. 1 is fed into a primary grinding ball mill (not shown) using a raw material feeder (not shown) (step S1, shown in FIG. 3).
S2). The primary grinding ball mill is a substantially cylindrical type ball mill capable of processing raw material dust continuously supplied by the raw material feeder, and has a rotation speed of the cylinder of 20 to 36.
rpm, the amount of balls serving as a grinding medium is 3 to 5 tons.
The supply amount of water containing the raw material dust fed to the primary grinding ball mill is 200 to 1000 liter / hr.
(Average: 270 l / hr), and the concentration of the raw material dust was 50 to 80 wt% (average: 65 wt%).

The residence time or treatment time of the raw material dust in such a primary grinding ball mill is about 60 to 120.
In this wet pulverization step, some of the impurities contained in the raw material dust can be separated from the iron powder. Here, the reason for performing the wet grinding process as described above is that the dust itself collected from the converter 11 is a wet powder containing a large amount of water as described above, and if the dry process is to be performed, the drying process is performed as a preliminary process. Is necessary, and since the subsequent pickling treatment is performed in a wet manner, a drying treatment is required again, which is uneconomical. Also,
If the pulverization is performed in a dry manner, dust is likely to be generated, and this dust countermeasure is required, resulting in a large cost for environmental measures.

Next, the treated material discharged from the primary grinding ball mill is subjected to a pre-cleaning akins having the same configuration as the wet classifier 19 shown in FIG. 1 to wash out the separated impurities (step S3). . here,
The velocity of the fluid that rises and overflows in the dust sedimentation tank 20 is 3 to 10 m / hr (average: 5 m / hr), and the supply amount of the washing water supplied to the open upper part of the sediment discharge means 21 is ^{3 to} 25 m ³ / hr (average: 5 m ³ /
hr). By the cleaning treatment using the pre-cleaning akins, a part of the impurities separated from the iron powder in the processed material is further separated and removed, and a minute portion in the iron powder is simultaneously removed, so that the particle size increases. The particle size distribution can be shifted in the direction.

Subsequently, the mixture discharged from the pre-cleaning akins is pulverized by a secondary grinding vibro mill (not shown) (step S4). The secondary grinding ore vibro mill is a vibration-type pulverizer having a capacity of 1000 liters.
hr (average: 270 l / hr), and the concentration of the raw material dust was 50 to 80 wt% (average: 65 wt%). By the wet grinding process using this secondary grinding vibro mill,
The impurities remaining on the iron powder in the mixture are further finely pulverized, so that a raw material dust having an improved efficiency of separating the iron powder from the impurities in the subsequent steps can be obtained. here,
FIG. 4 shows an example of impurities present in a processed material containing iron powder.
This shows the change in the aO concentration. The CaO concentration which was in the range of 2 to 7 wt% before being charged into the primary grinding ball mill (A in FIG. 4) was changed after the treatment with the pre-cleaning Akins (B in FIG. 4). ) Shows that the amount is reduced to the range of 0.5 to 5 wt%. However, such raw material dust (wet pulverized material) still has many impurities remaining,
The reducing agent used for the regeneration treatment of the etching waste liquid has insufficient purity and cannot be used as it is. For this reason, it is necessary to further perform a cleaning classification process on the raw material dust using a hydroxyl cleaning device 23 as shown in FIG.

First, as the first step (step S5) of the cleaning process using the hydroxylic acid washing device 23, the raw material dust is introduced into the water precipitation tank 26 from above the water washing device 24 via the raw material dust supply pipe 29. As a result, the iron powder portion having a large specific gravity in the raw material dust gradually precipitates, forming a precipitate layer at the bottom of the water precipitation tank 26. Then, the spiral body 28 disposed in the water sediment discharge means 27 is rotated by a driving device such as a motor. On the other hand, at this time, the washing water is supplied using the water supply pipe 25 to ^{3 to} 25 m ³ / hr (average: 25 m ³ / h).
r), a downward flow due to the washing water is formed in the water sediment discharge means 27 and the water sedimentation tank 2
6, the raw material dust is charged, and an overflow flow composed of a portion having a low specific gravity is generated.
Adjust to a range of 0 m / hr (average: 5 m / hr). Thereby, the separation and purification of the raw material dust are efficiently performed.

By the above operation, the fine powder portion in the raw material dust is washed away together with the overflow, and the coarse particle portion is selectively discharged from the upper part of the water precipitate discharge means 27 as the cleaning iron powder. Since most of the impurities are contained in the fine powder portion, impurities (CaO) in the raw material dust are largely removed in the range of 0.3 to 1.7 wt% as shown in FIG. A washed iron powder having a particle size distribution shifted to a coarse particle side is obtained. Next, as a second stage (step S6) using the hydroxylic acid washing device 23, the obtained washed iron powder is put into the acid precipitation tank 32 from above the acid washing device 30 via the supply pipe. As a result, a portion having a large specific gravity in the washed iron powder gradually precipitates, and a layer of a precipitate is formed at the bottom of the acid precipitation tank 32.

The helical member 34 disposed in the acid-liquid-precipitate discharge means 33 is driven to rotate by a motor, and an overflow flow is formed in the acid-precipitation tank 32. The rising speed is 3 to 10 m / hr (average). : 5 m / hr). On the other hand, at this time, 98 wt% sulfuric acid having a specific gravity of 1.9 is supplied at a supply rate of 30 to 100 liter / hr using the acid solution supply pipe 31, and the downward flow caused by the acid solution is caused to pass through the acid solution precipitate carrying means. 33. At this time, the hydrogen ion concentration (pH) of the acid solution in the acid cleaning device 30 is 0.1.
The range was 5 to 3.0. By the above operation, the fine powder portion in the washed iron powder flows down and accumulates in the acid precipitation tank 32, and at the same time, the washed iron powder is caused by the acid solution flowing down along the acid solution precipitate carrying-out means 33 and the overflow flow in the solution. The impurities therein are effectively eluted and removed, and the coarse-grained portion including the purified iron powder is selectively discharged from the upper part of the acid solution precipitate carrying-out means 33, and the supernatant waste liquid in the acid precipitation tank 32 is discharged from the upper part. .

The impurity (CaO) in the purified iron powder is in the range of 0.01 or less as shown in FIG.
It is possible to obtain a treated product containing purified iron powder that has been significantly removed to 0.10 wt%. FIGS. 5 and 6 are graphs each showing the relationship between the CaO concentration in the finally obtained purified iron powder and the basic unit of hydrochloric acid and the basic unit of sulfuric acid used in the acid washing apparatus 30. As shown in FIG. 5 and FIG. 6, when the acid unit is too low, the ratio deviating from the allowable amount of CaO in the product increases, and when the acid unit exceeds the saturation amount, the decrease in the CaO concentration decreases, Acid costs, waste acid treatment costs, and equipment maintenance costs increase. Therefore, in consideration of the above, it is possible to reduce the sulfuric acid unit required to obtain 1 ton of purified iron powder as a product to 10 to 400 liters,
More preferably, it is desirable to be in the range of 270 to 400 liters. The basic unit of hydrochloric acid can be 25 to 700 liters / ton, more preferably 5 to 700 liters / ton.
It is desirable to set in the range of 50 to 700 liters. The sulfuric acid and hydrochloric acid used here have a concentration corresponding to a hydrogen ion concentration (pH) in the range of 0.5 to 3.0, and may be treated depending on factors such as the content of CaO in the raw material dust and other components. 5 and 6 show that the resulting CaO concentration in the iron powder varies.

Next, in step S7, using a secondary cleaning akins having the same structure as that of the water cleaning device 24,
The treated material after the acid cleaning treatment was treated to wash the treated material that was acidic. At this time, the remaining acid solution can be removed by supplying cleaning water such as industrial water at a supply speed of 1 to 10 m ³ / hr. And in step S8,
The treated product after the acid solution treatment is passed through a flash dryer to obtain 150 to 2
Water was removed in an air stream at 50 ° C. The particle size distribution of the purified iron powder after drying was measured to be 750 to 150 μm.
m, 150-105 μm, 105-74 μm, 7
4 to 63 μm, 63 to 44 μm, 44 μm or less are 0 to 20 wt%, 5 to 40 wt%, 20
~ 60wt%, 5 ~ 25wt%, 10 ~ 30wt
%, 1 to 19 wt%. In addition, the said range may be 710-150 micrometers. A typical composition of such purified iron powder is that the total Fe including Fe, FeO, and Fe ₂ O ₃ is 96 wt% or more, metal Fe is 92 wt% or more, FeO is 6 wt% or less, and CaO is 0 wt% or less. .
The range was 5 wt% or less, SiO ₂ was 0.1 wt% or less, and carbon (C) was 0.7 wt% or less.

In the last step S9, a tiler (Ty
ler) The purified iron powder is classified using a vibrating sieve having any one of a standard sieve in a range of 100 mesh to 150 mesh, and the iron powder on the sieve is used for copper removal in etching waste liquid treatment. And the iron powder under the sieve can be used as purified iron powder for removing nickel. The 100 mesh and 150 mesh Tyler sieves each have an opening of 147 meshes.
The sieve has a size of μm or 104 μm.

The embodiment of the present invention has been described above.
The present invention is not limited to these embodiments, and all changes in conditions without departing from the gist are within the scope of the present invention. For example, in the present embodiment, the case where the water washing device and the acid washing device are respectively different independent devices has been described. However, such a water washing process and an elution washing process are performed using the same wet classifier. You can do it too. In this case, the washing iron powder discharged from the wet classifier can be temporarily stored in a storage tank, and the washed iron powder taken out of the storage tank can be treated using the same wet classifier. Further, by combining a plurality of sets of a water washing device and an acid washing device as necessary, it is possible to repeat the water washing process and the acid washing process to more reliably remove impurities in the raw material dust.

[0023]

In the method for producing iron powder from steelmaking furnace dust according to any one of claims 1 to 4, the lower part of the water sediment discharge means is disposed obliquely in the water sedimentation tank to which the raw material dust is supplied. The helical body provided inside the sediment discharging means is driven to rotate to move the sediment, and a downward flow is formed by water spouted from directly above the helical body, whereby the ascending sediment is moved. The fine powder portion containing the impurities is washed away by the washing water, and the washed and classified washed iron powder can be obtained from the upper portion of the water sediment discharge means.
Next, the spiral of the acid solution precipitate carrying-out means, which is inclined and disposed in the acid precipitation tank to which the washed iron powder is supplied, is rotated to move the precipitate upward, and hydrochloric acid, sulfuric acid or the like is immediately above the spiral. By supplying the acid solution of the above to form a downward flow, impurities adhering to the iron powder in the ascending moving precipitate can be effectively eluted with the acid solution to obtain purified iron powder. Therefore, it is possible to continuously process the dust generated from the steelmaking furnace, and to produce high-purity purified iron powder with little variation in purity and in large quantities at low cost.

In particular, in the method for producing iron powder from steelmaking furnace dust according to claim 2, the CaO concentration of the refined iron powder is set to 0.1.
Since it is less than 1 wt%, even when this purified iron powder is used as a reducing agent in the regeneration treatment of the etching waste liquid,
aO does not accumulate during the regeneration cycle. For this reason, the CaO concentration of the etching solution can be maintained at a predetermined level or less, and the etching can be easily performed under appropriate conditions. In the method for producing iron powder from steelmaking furnace dust according to claims 3 and 4, since a sulfuric acid or hydrochloric acid solution having a hydrogen ion concentration limited to a specific range is used for the acid solution,
The amount of impurities such as CaO in the refined iron powder can be maintained at a predetermined level, and the acid solution cost, the waste acid treatment cost,
Equipment maintenance costs can be managed within an appropriate range. In the method for producing iron powder from steelmaking furnace dust according to claim 4, since the acid solution is sulfuric acid and the amount of sulfuric acid used is set to a specific range, impurities can be removed in a more optimized range. Yes, it is possible to produce highly pure iron powder with little variation.

[Brief description of the drawings]

FIG. 1 is a partial configuration diagram of steelmaking equipment to which a method for producing iron powder from steelmaking furnace dust according to an embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram of a hydroxylic acid washing apparatus to which the method for producing iron powder is applied.

FIG. 3 is a flowchart of the method for producing iron powder.

FIG. 4 is a graph showing changes in CaO concentration in iron powder in each processing step.

FIG. 5 is a graph showing the relationship between CaO concentration in product iron powder and basic unit of hydrochloric acid.

FIG. 6 is a graph showing the relationship between the CaO concentration in the product iron powder and the specific unit of sulfate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Steelmaking equipment 11 Converter (steelmaking furnace) 12 Hood part 13 Exhaust system 14 Chimney 15 First injection port 16 Second injection port 17 Dust treatment tank 18 Thickener 19 Wet classifier 20 Dust sedimentation tank 21 Precipitate discharging means 22 Spiral body 23 Hydroxylic acid washing device 24 Water washing device 25 Water supply pipe 26 Water sedimentation tank 27 Water sediment discharge means 28 Spiral body 29 Raw material dust supply pipe 30 Acid cleaning equipment 31 Acid liquid supply pipe 32 Acid sedimentation tank 33 Acid liquid sediment discharge means 34 Spiral

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsumasa Mito, Inventor 1-3-1, Otani, Yawatahigashi-ku, Kitakyushu-shi, Fukuoka Prefecture Astec Irieuchi Co., Ltd. No.3-1, Astec Irie Co., Ltd.

Claims (4)

[Claims] 1. A raw material dust is recovered from a dust iron powder containing impurities such as CaO generated from a steel making furnace by a wet method,
A wet pulverizing step of pulverizing the raw material dust using a pulverizer such as a ball mill or a vibro mill; a water pulverizing step of washing the wet pulverized product generated in the step with water and removing the impurities together with fine powder to obtain a washed iron powder; An elution washing step of eluting and removing the remaining impurities by pickling the washed iron powder and removing the remaining impurities, wherein the water washing step is disposed inclined and rotationally driven. From the step of washing the raw material dust carried out by the water jetted from the upper part of the spiral while gradually discharging the raw material dust put into the water sedimentation tank by the water sediment discharging means having the spiral body. In the elution washing step, the washing iron powder charged into the acid solution precipitating tank is gradually removed by an acid solution sediment carrying-out means having a spirally arranged and rotationally driven spiral. And pickling the washed iron powder carried out by an acid solution such as hydrochloric acid or sulfuric acid spouted from the upper part of the spiral while discharging the solution, and removing the CaO from the acid solution precipitate discharging means as much as possible. A method for producing iron powder from steelmaking furnace dust, characterized by obtaining iron powder. 2. The purified iron powder has a CaO concentration of 0.1 w
The method for producing iron powder from steelmaking furnace dust according to claim 1, wherein the content is less than t%. 3. The method according to claim 1, wherein the acid solution has a hydrogen ion concentration (pH) of 0.1.
The method for producing iron powder from steelmaking furnace dust according to claim 1 or 2, which is a sulfuric acid or hydrochloric acid solution of 5 to 3.0. 4. The method for producing iron powder from steelmaking furnace dust according to claim 2, wherein the acid solution is sulfuric acid, and the amount of sulfuric acid used is 10 to 400 liters per ton of purified iron powder.