JP4750846B2 - Recycling method of zinc-containing converter dust - Google Patents

Description

The present invention divides zinc-containing converter dust generated in the converter process during the production of steel into a dust content with a low zinc content and a dust content with a high zinc content, and efficiently recycles it to a blast furnace, converter or electric furnace. The present invention relates to a method for recycling furnace dust.

The production volume of galvanized steel sheets used in automobile steel sheets has increased rapidly over the past 10 years, and as a result, the amount of galvanized steel sheet scraps put into a converter and melted and reused has also increased. Yes. Therefore, much zinc has come to be included in the dust generated from the converter.
Conventionally, converter dust recovered by an exhaust gas recovery system (OG recovery system) for a non-combustion converter has been recycled as a blast furnace raw material through a sintering process. Such blast furnace recycling of converter dust can be performed without problems for converter dust having a low zinc content (1% by mass or less). However, as described above, when converter dust having a high zinc content is used as a blast furnace raw material, there is a problem of causing operational troubles such as shelves.
In addition, some of the zinc-containing converter dust is recycled to the converter, but if the entire amount of converter dust generated from the converter is put into the converter, the zinc content in the converter dust generated again will be increased. When the concentration of the steel progresses and exceeds the limit concentration (which is said to be about 8% by mass) that finally affects the molten steel components, there is a problem that recycling to the converter becomes difficult.

Therefore, fine dust containing zinc is disposed of in landfill despite the high iron content (about 70% by mass). However, it is said that landfill disposal will not be possible in the near future due to the depletion of landfill sites and rising landfill disposal costs.
Under such circumstances, proposals have been made regarding a dezincing method for separating and recovering zinc in converter dust. FIG. 4 shows an example of a conventional method for dezincing converter dust. The zinc-containing converter dust collected in the collected water by the non-combustion type dust collector 41 provided above the converter is conveyed to the coarse particle separator 42, where the coarse particle fraction ( Coarse grain dust) is separated. The zinc-containing fine particle dust that has passed through the coarse particle separator 42 is concentrated by the thickener 43 and then dehydrated by the filter press 44. The zinc-containing fine dust thus obtained is subjected to a drying process 45, a molding 46, and a dezincing process 47. The dezincing treatment 47 is performed, for example, by reducing the iron oxide in the dust at 1100 to 1300 ° C. in a rotary reduction furnace and simultaneously reducing the contained zinc and separating and recovering the vaporized metallic zinc (for example, Japan JP-A-2001-294942). In addition, the converter gas discharged | emitted from the non-combustion type dust collector 41 is accumulate | stored in a gas holder.

The above-described conventional method for dezincing converter dust has high dezincing efficiency, and iron oxide in the converter dust is also reduced at the same time, which is convenient for recycling the converter dust in a blast furnace or converter. .
However, there is a problem that a large equipment construction cost is required and the processing cost is high.
Further, in the previous stage of the dezincing treatment, if low-zinc content dust that can be recycled in a blast furnace or a converter without dezincing treatment can be separated and recovered from the converter dust at low cost and selectively. Since the amount of converter dust to be dezinced can be reduced, the dezincing equipment can be downsized and the processing cost can be reduced.

Thus, for example, Japanese Patent Application Laid-Open No. 2004-122024 and Japanese Patent Application Laid-Open No. 2005-21841 propose methods for separating dust having a low zinc content from converter dust.
This Japanese Patent Application Laid-Open No. 2004-122024 includes at least two stages of wet cyclones with different classification performances in series, and after separating the slurry containing converter dust into an overflow and an underflow with the previous wet cyclone, A method is disclosed in which the underflow is further separated into an overflow and an underflow by a subsequent wet cyclone. By this upstream wet cyclone, only dust with large particles in the slurry can be captured by underflow, so that the risk of blockage of the pipe can be avoided without increasing the solid phase rate of underflow. In addition, by treating the separated underflow with a subsequent wet cyclone, more than half of the zinc is recovered on the overflow side, while most of the iron is collected in the underflow, so the zinc in the slurry And iron can be separated efficiently.

At this time, the dust in the underflow separated by the subsequent wet cyclone is reused as a sintering raw material. However, there is no description about reusing as another raw material, that is, a converter raw material or an electric furnace raw material, and the usage of the recovered dust cannot be further expanded. This is thought to be because further processing is required to reuse the recovered dust as a converter raw material or an electric furnace raw material, and the processing conditions are not set at this time.
For example, if the dust is simply dried, it takes time to remove the moisture, resulting in a reduction in dust processing efficiency. In addition, even if it dry-processes, when charging the whole quantity into a converter or an electric furnace as it is, the quantity to which dust will fly increases and there exists a problem which a working environment deteriorates.
Here, in order to increase the processing efficiency of dust, it is conceivable to shorten the time required for the drying process, but in this case, a steam explosion may occur when charging the converter or the electric furnace.
For this reason, when the amount of dust collected in the future increases and exceeds the amount that can be reused as a sintering raw material, as described above, landfill processing must be performed.

Japanese Patent Application Laid-Open No. 2005-21841 discloses a method of separating a slurry containing converter dust into a slurry containing dust having a high zinc content and a slurry containing dust having a low zinc content by a wet separator. Is disclosed.
However, since this method is a method for obtaining zinc product raw materials and metal raw materials from converter dust, before separating the slurry containing converter dust with a wet separator, the pH of the slurry is adjusted to obtain the zinc content. The rate is increasing. Thus, since it is not a method of actively removing zinc from the slurry, a large amount of zinc may remain in the separated dust having a low zinc content.
Therefore, there is a problem in using the separated dust having a low zinc content as a raw material for a blast furnace, a converter, or an electric furnace without performing a dezincing treatment.

The present invention has been made in view of such circumstances, from zinc-containing converter dust generated in the converter process during the production of steel, divided into a dust content with a low zinc content and a high dust content, blast furnace or converter or It aims at providing the recycling method of the zinc containing converter dust which can reduce the cost which a dezincing process requires by efficiently recycling to an electric furnace.

In the method for recycling zinc-containing converter dust according to the present invention in accordance with the above object, coarse particles are separated from converter dust collected by a wet dust collector, and the zinc content is 0.5 mass% or more and 10 mass. %, And a first step of obtaining a zinc-containing fine dust having an iron content of 50% by mass or more and 90% by mass or less,
The zinc-containing fine dust is hydrocyclone, the average particle size is in the range of 8 μm to 25 μm, and the zinc content is 1% by mass or less. A second step in which the content of zinc is in the range of 5 μm or less and the zinc content exceeds 1% by mass and is separated into fine zinc dust of high zinc content containing more iron oxide than the medium fine dust;
The medium fine dust is not subjected to dezincing treatment, and a third step is performed by adding a binder and pressing to form an agglomerate used as a converter raw material or an electric furnace raw material,
The fine-grained dust is subjected to a dezincing treatment after drying, and is used as a blast furnace raw material as it is or as an agglomerated material as a converter raw material.

The zinc-containing fine dust described above is obtained by trapping and solidifying gaseous zinc metal on the surface of the fine dust. This is because metallic zinc has a low boiling point and therefore exists in a gaseous state in the converter. For this reason, the zinc-containing fine-grained dust has a higher zinc content as the particle size of the fine-grained dust becomes smaller and the ratio of the surface area to the mass becomes higher.
In addition, by classifying the zinc-containing fine dust with a hydrocyclone, it becomes possible to separate into medium fine dust having a large average particle size and fine dust having a small average particle size.
For this reason, the separated medium fine particle dust has a low zinc content (zinc content is 1% by mass or less), and can be recycled without dezincing treatment.

In addition, the zinc-containing fine particle dust has an oxide film formed on the surface thereof when oxygen penetrates from the surface. Note that the thickness of the oxide film is substantially constant regardless of the particle diameter under the same conditions. For this reason, as for the zinc-containing fine particle dust, the particle size of fine particle dust becomes small, and the content rate of iron oxide becomes high, so that the ratio of the surface area with respect to mass becomes high. Therefore, fine particle dust contains more iron oxide than medium fine particle dust.
In this way, the medium fine dust has a high content of metallic iron and low zinc content, so it can be recycled as a converter raw material or an electric furnace raw material after it is agglomerated, so it is more than recycled in a blast furnace. , Energy costs can be reduced.

Moreover, when manufacturing an agglomerate from medium fine particle dust, since the medium fine particle dust is press-processed by high pressure and a binder is added to medium fine particle dust, the shape at the time of agglomeration can be maintained. Thereby, workability at the time of transporting the agglomerates is improved, and dangers such as a steam explosion and dust scattering during charging into the converter or electric furnace can be reliably prevented.
In this way, medium-dust dust can be agglomerated for use as a converter raw material or an electric furnace raw material by pressing a binder without adding a dezincing treatment. Expenses and processing costs can be reduced.
On the other hand, dedusting is performed on fine-grained dust, but since medium-fine dust that does not require dezincing is separated in advance, the amount of processing is reduced and the processing cost required for dezincing is reduced. I can plan.

In the method for recycling zinc-containing converter dust according to the present invention, a part of the medium fine dust separated in the second step may be dried and used as a blast furnace raw material without dezincing treatment. preferable.
Thus, by drying the medium fine particle dust and using it as a blast furnace raw material, it is not necessary to make an agglomerate, and the processing efficiency of the medium fine particle dust can be improved.

In the method for recycling zinc-containing converter dust according to the present invention, the press treatment in the third step adjusts the water content of the medium fine dust separated by the hydrocyclone to 10% by mass or more and 15% by mass or less. At the same time, it is preferable that the agglomerate is produced by adding the binder and kneading, followed by pressure extrusion in an extrusion press.
In this way, the moisture content of the medium fine dust is adjusted to 10% by mass or more and 15% by mass or less, so that the moisture content of the medium fine dust is reduced and agglomeration using a simple extrusion press device is possible. become.

In the method for recycling zinc-containing converter dust according to the present invention, the press treatment in the third step adjusts the water content of the medium fine dust separated by the hydrocyclone to 30% by mass or more and 60% by mass or less. At the same time, after the binder is added and stirred, the plate-like agglomerate is preferably produced by molding with a high-pressure filter press that is squeezed at a pressure of 5 MPa to 20 MPa.
Thus, since the medium fine particle dust whose water content is adjusted to 30% by mass or more and 60% by mass or less is sent to the high pressure filter press, the filling operation of the medium fine particle dust to the high pressure filter press can be carried out smoothly.
In addition, since the medium fine dust has good dewatering efficiency, when the medium fine dust is squeezed with a high-pressure filter press, the dehydrated cake is processed more than with the high-pressure filter press for fine dust that has not been separated. The moisture content can be lowered, the agglomerates can be densified, the powdering rate can be reduced, and the efficiency of the recycling work can be improved. Further, since the binder is added to the medium fine dust, the shape when agglomerated can be maintained.

In the method for recycling zinc-containing converter dust according to the present invention, a part of the medium fine dust separated in the second step is used as a converter raw material or an electric furnace raw material as it is after drying without dezincing treatment. It is preferable.
Here, the medium fine dust separated by the hydrocyclone has a property close to that of coarse dust having a low zinc content and a high content of metallic iron. Therefore, metal iron is contained at a higher content than medium fine dust, and medium fine dust can be treated in the same manner as coarse dust that is currently used effectively in applications such as recycling.
Therefore, the processing cost can be greatly reduced as compared with the recycling in the blast furnace accompanied by the conventional dezincing treatment.

It is the schematic of the zinc-containing fine particle dust separation apparatus used for the recycling method of the zinc-containing converter dust which concerns on one Example of this invention. (A), (B) is a schematic process drawing of the 3rd process of the recycling method of the same zinc-containing converter dust, respectively. It is a schematic process drawing of the 3rd process and 4th process concerning a modification. It is explanatory drawing which shows the dezincification processing method of the zinc containing converter fine grain dust which concerns on a prior art example.

Subsequently, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
As shown in FIGS. 1 to 3, the zinc-containing converter dust recycling method according to one embodiment of the present invention is a zinc-containing converter dust recovered by a wet dust collector (hereinafter also referred to simply as converter dust). ), A second step of separating the zinc-containing fine dust from a low-zinc medium fine dust and a high-zinc fine dust, and the separated medium fine dust. It has the 3rd process of making an agglomerate without dezincing a grain dust, and the 4th process of dezincing the separated fine grain dust. This will be described in detail below.

First, the first step will be described.
Zinc-containing converter dust discharged from a converter (not shown) charged with zinc-containing scrap is collected in a wet dust collector together with the generated OG gas, where OG gas, which is a gaseous component, is separated. . This wet dust collector is a non-combustion type installed in the upper part of the converter, but is not limited to this.
And the dust collection water containing the zinc-containing converter dust collected by the wet dust collector is conveyed to a coarse grain separator via a soot. This coarse particle separator is designed to collect particles having a relatively high specific gravity and a large particle size (coarse particles), and thereby, a coarse particle component having a large particle size (for example, a particle size) from converter dust. Distribution: about 40 to 200 μm, average particle size: about 100 μm).

The zinc-containing fine-grained dust obtained by separating the coarse particles with a coarse particle separator has a zinc content of 0.5% by mass to 10% by mass and an iron content of 50% by mass to 90% by mass. belongs to. Note that zinc-containing fine dust having a zinc content of less than 0.5% by mass can be recycled in a blast furnace without dezincing treatment. On the other hand, the zinc content of the zinc-containing fine dust does not exceed 10% by mass.
Further, the particle size distribution of the zinc-containing fine dust is, for example, about 0.1 to 80 μm, and those having a particle size of 10 μm or less occupy 80% of the total mass.
Thus, the zinc-containing fine-grained dust has a higher zinc content than the conventional converter dust, and also has an iron content higher than that of the blast furnace dust.
As shown in FIG. 1, the dust-collected water containing the zinc-containing fine dust is further supplied to the thickener 10, concentrated, processed into a slurry, and then sent to the first slurry receiving tank 12 by the pressure pump 11. Sent.

Next, the second step will be described.
The zinc-containing fine-grain dust in the slurry sent to the first slurry receiving tank 12 is provided in the first slurry receiving tank 12 and has a stirring blade and a first mechanical stirrer 13 having a motor for driving the stirring blade. And uniformly dispersed in the first slurry receiving tank 12.
The processed product in which the zinc-containing fine dust is dispersed is conveyed to a hydrocyclone (also referred to as a liquid cyclone) 15 by the first slurry pump 14. And the zinc-containing fine particle dust in a processed material is isolate | separated by the hydrocyclone 15 into the low-zinc medium fine particle dust and the high-zinc fine particle dust. The hydrocyclone 15 is conventionally known and separates zinc-containing fine dust into medium fine dust and fine dust using centrifugal separation.

The separated medium fine particle dust has an average particle size in the range of 8 μm to 25 μm (for example, a particle size distribution of about 5 to 80 μm) and a zinc content of 1% by mass (preferably 0.5%). Mass%) or less.
The fine particle dust has an average particle size in the range of 1 μm to 5 μm (for example, a particle size distribution of about 0.1 to 20 μm), and the zinc content exceeds 1% by mass (medium fine particle dust When the zinc content is 0.5% by mass or less, it exceeds 0.5% by mass) and contains more iron oxide than the medium fine dust.

Most of the fine particle dust separated by the hydrocyclone 15 is recovered from the overflow pipe 16 and most of the medium fine particle dust is recovered from the underflow pipe 17.
Here, Table 1 shows the analysis results of the dust collected from the overflow pipe 16 and the dust collected from the underflow pipe 17. This analysis result is based on a classification test (d ₅₀ 20 μm) using a WARMAN 6C type hydrocyclone (spigot diameter 30 mm) as the hydrocyclone and the pump (first slurry pump) flow rate of 0.4 m ³ / min. It is the result obtained by performing.

In Table 1, "M-Fe" represents metallic iron, and "T-Fe" represents total iron.
As is apparent from Table 1, from the underflow pipe 17 of the hydrocyclone 15, by classification with the hydrocyclone 15, particles having a particle diameter exceeding 20 μm are 70 mass%, and the zinc content is 0.5 mass%. A dust having a low metallic iron content of 70% by mass is separated and recovered.
Further, from the overflow pipe 16 of the hydrocyclone 15, high-zinc dust having a particle size of 20 μm or less and having a zinc content exceeding 1 mass% is separated and recovered by classification with the hydrocyclone 15. .

As described above, the dust having a large particle size has a small amount of zinc adhered, while the dust having a small particle size has a large amount of zinc adhered.
Here, the result of investigating the relationship between the particle size and the amount of zinc adhered will be described. In the test, zinc-containing fine dust (zinc content: 2.46%), which was recovered from the converter by a wet dust collector and separated by a coarse separator, was used after drying. did. Then, the dried product was classified into a particle size of 20 μm or more and less than 20 μm by a sieve classification method, and the mass distribution ratio and the zinc content were analyzed.
The analysis results are shown in Table 2.

As is apparent from Table 2, the zinc content of zinc-containing fine dust having a particle size of 20 μm or more is 0.4% by mass, while the zinc content of zinc-containing fine dust having a particle size of less than 20 μm is 2. It was 8 mass%.
This result corresponds to the zinc content of each dust obtained from the overflow and underflow shown in Table 1.
That is, it was confirmed that the amount of zinc attached to the dust having a large particle size was small, and the amount of zinc attached to the dust having a small particle size was increased.

From the above, the medium fine dust has a zinc content of 1% by mass or less, and the contained zinc does not affect the molten steel components in the converter. It can be used for furnace recycling or electric furnace recycling.
However, medium fine dust has a high moisture content (about 30% by mass), and if it is inserted into a converter or electric furnace without being dried, it may cause a steam explosion or abnormal combustion. In addition, since the medium fine particle dust has a small average particle size, there is a possibility that it will be pulverized and scattered when it is charged into a converter or an electric furnace in a state of fine particles. For this reason, a binder is added to the medium fine particle dust to form an agglomerate by pressing, and then charged into a converter or an electric furnace.
Hereinafter, the 3rd process which performs the agglomeration process of a medium fine dust is demonstrated, referring FIG. 2 (A) and (B).

As shown in FIG. 2A, the slurry-like medium fine dust collected from the underflow pipe 17 of the hydrocyclone 15 is conveyed to a stirring rotary dryer and kneaded with a binder. Further, the kneaded product of the medium fine dust and the binder is dried until the water content becomes about 10% by mass or more and 15% by mass or less, and then put into an extrusion type press apparatus. And it extrudes by pressure with an extrusion-type press apparatus, and is further dried and agglomerated as needed. In addition, the moisture content of the above-described medium fine particle dust may be adjusted before adding the binder, or may be adjusted after adding the binder.
The agglomerate (dust cake) thus obtained is charged into the converter as a converter raw material, for example, via a scrap chute. Moreover, it is charged into the electric furnace as the electric furnace raw material.

Here, the agglomeration conditions such as the shape and size of the agglomerate, the type and addition amount of the binder, and the press pressure are not particularly limited as long as pulverization can be suppressed during charging into the converter or electric furnace.
In addition, as a binder, for example, cement, lime, bentonite, etc. are used, and this is added, for example, about 5% by mass of medium fine dust, and the press pressure is 5 MPa, so that the powdering rate is 5% by mass or less. Can be suppressed.
Further, in order to prevent steam explosion and abnormal combustion when charging into the converter or electric furnace, it is necessary to keep the water content of the agglomerate below a certain amount. For example, when the amount of agglomerate charged into a 300-ton converter is 1 ton or less per time, it can be used as it is after pressing, but the amount charged exceeds 1 ton per time. In some cases, further drying is required.
In addition, although the above-mentioned extrusion-type press apparatus is a conventionally well-known apparatus which extrudes a kneaded material from an opening part, it is not limited to this.

Further, as shown in FIG. 2B, the slurry-like medium fine dust collected from the underflow pipe 17 of the hydrocyclone 15 is conveyed to a slurry tank (not shown) in the form of a slurry. Water is added so that the rate is 30% by mass or more and 60% by mass or less (preferably, the lower limit is 40% by mass, further 45% by mass, and the upper limit is 55% by mass). A binder is further added to the slurry-like medium fine dust (for example, about 5 to 15% by mass) and stirred, and conveyed to a high-pressure filter press that squeezes at a pressure of 5 MPa or more and 20 MPa or less for dehydration treatment. To be molded.
Thereby, a plate-like agglomerate (dust cake) having a water content of about 15% by mass and a thickness of 20 to 40 mm (in this example, about 30 mm) is obtained. Since this agglomerate is dense and can reduce the powdering rate, the work efficiency can be improved.

In this high pressure filter press, the medium fine dust is blocked from the atmosphere by the water coexisting in the slurry, so that the metallic iron contained in the medium fine dust is agglomerated without being oxidized. Thereafter, the agglomerate is further dried (moisture content is, for example, about 2 to 5% by mass) as necessary, and charged into a converter or an electric furnace.
Also in this case, the agglomeration conditions such as the shape and size of the agglomerate, the type and addition amount of the binder, and the press pressure are not particularly limited as long as pulverization can be suppressed during charging into the converter or electric furnace.
The above-described high-pressure filter press is a conventionally known apparatus that pressurizes while filling slurry-like medium fine dust between adjacent filters, but is not limited to this as long as the above-described press pressure can be achieved. Absent.

In the embodiment described above, the case where the medium fine dust is agglomerated and used as the converter raw material or the electric furnace raw material has been described. However, the medium fine dust with a zinc content of 1% by mass or less corresponds to 20% by mass of the zinc-containing fine dust, and the ratio of this dust to the blast furnace raw material is as small as several mass%. Even if it is inserted into the blast furnace without doing it, it will not cause operational troubles such as shelves.
Therefore, a part of medium fine dust (for example, about 5 to 95% by mass of all medium fine dust separated by hydrocyclone 15) is dried without performing dezincing treatment as shown in FIG. And after performing shaping | molding, you may charge to a blast furnace as a blast furnace raw material (it may be used as a sintering raw material of a blast furnace).

Subsequently, the fourth step will be described.
As shown in FIG. 1 and FIG. 3, the fine particle dust separated by the hydrocyclone 15 is sent to the second slurry receiving tank 18, and then the second dust provided in the second slurry receiving tank 18. The mixture is stirred by a mechanical stirrer 19 and conveyed to a filter press 21 by a second slurry pump 20 while preventing sedimentation of fine particle dust.
As shown in FIG. 3, the fine-grain dust is dehydrated by a filter press 21 and dried until the water content (water content) becomes about 10% by mass, followed by molding and dezincing treatment. By this dezincing treatment, zinc is vaporized and iron oxide is reduced to become metallic iron (M-Fe), so that it is directly used as a blast furnace raw material for blast furnace recycling. The molding and dezincing treatment can be performed by any method disclosed in, for example, Japanese Patent Laid-Open No. 7-70662 or Japanese Patent Laid-Open No. 8-260066.
Further, the fine particle dust can also be agglomerated by using the above-mentioned medium fine particle agglomeration treatment, and used as a converter raw material.

As mentioned above, although the embodiment of the present invention has been described, the present invention is not limited to this embodiment, and can be changed without changing the gist of the invention. A case where the method for recycling zinc-containing converter dust of the present invention is configured by combining a part or all of them is also included in the scope of rights of the present invention.
For example, in the method for recycling zinc-containing converter dust of the above embodiment, medium fine dust is mixed with lime powder, coke, fine ore, etc. and charged into a sintering machine, and charged into a blast furnace as sintered ore. May be.
In addition, after drying a part of the medium fine dust (for example, about 5 to 30% by mass of the total medium fine dust) until the water content becomes 2 to 5% by mass without dezincing treatment, As it is, it can be used as a converter raw material or an electric furnace raw material in the same way as coarse dust.
And a 3rd process and a 4th process may be performed simultaneously in parallel, and any may be performed first.

By separating the zinc-containing converter dust generated in the converter process during the production of steel into dust with low zinc content and high dust, processing and equipment costs are high for dust with low zinc content. Without being dezinced, it can be efficiently and efficiently recycled to a blast furnace, converter or electric furnace. Moreover, since the dust content with a low zinc content which does not require a zinc removal process is isolate | separated beforehand about the dust content with a high zinc content rate, a processing amount can be reduced and the reduction of the processing cost required for a zinc removal process can be aimed at. .

Claims (5)

Coarse particles are separated from converter dust collected by a wet dust collector, and the zinc content is 0.5 mass% to 10 mass% and the iron content is 50 mass% to 90 mass%. A first step to obtain fine dust,
The zinc-containing fine dust is hydrocyclone, the average particle size is in the range of 8 μm to 25 μm, and the zinc content is 1% by mass or less. A second step in which the content of zinc is in the range of 5 μm or less and the zinc content exceeds 1% by mass and is separated into fine zinc dust of high zinc content containing more iron oxide than the medium fine dust;
The medium fine dust is not subjected to dezincing treatment, and a third step is performed by adding a binder and pressing to form an agglomerate used as a converter raw material or an electric furnace raw material,
The method for recycling zinc-containing converter dust, characterized in that the fine-grained dust has a fourth step of dezincing after drying and directly using it as a blast furnace raw material or an agglomerated raw material as a converter raw material. . 2. The method for recycling zinc-containing converter dust according to claim 1, wherein a part of the medium fine dust separated in the second step is dried and used as a blast furnace raw material without dezincing treatment. A method for recycling zinc-containing converter dust characterized by The zinc-containing converter dust recycling method according to claim 1, wherein the press treatment in the third step adjusts the moisture content of the medium fine dust separated by the hydrocyclone to 10 mass% or more and 15 mass% or less. The zinc-containing converter dust recycling method is characterized in that the agglomerate is produced by adding the binder and kneading the mixture and then pressing and extruding the mixture into an extrusion press. The zinc-containing converter dust recycling method according to claim 1, wherein the press treatment in the third step adjusts the water content of the medium fine dust separated by the hydrocyclone to 30% by mass or more and 60% by mass or less. In addition, the plate-like agglomerate is produced by forming the agglomerate in a plate shape by molding with a high-pressure filter press that is squeezed at a pressure of 5 MPa or more and 20 MPa or less after adding the binder and stirring. Recycling method. 2. The method for recycling zinc-containing converter dust according to claim 1, wherein a portion of the medium fine dust separated in the second step is not subjected to dezincing treatment, and is directly converted into a converter raw material or an electric furnace raw material after drying. A method for recycling zinc-containing converter dust characterized in that:

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