JP2005089794A - Method for effectively utilizing iron-making dust as resource - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for effectively utilizing iron-making dust as a resource with which the iron-making dust generated from the iron-making process of reducing, melting, refining, etc., are fully regeneration-utilized in the iron-making process, and zero-emission of the iron-making dust is realized and an infrastructure scale needed in a plurality of iron-works can be minimized. <P>SOLUTION: In the method for effectively utilizing the iron-making dust as the resource generated in the iron-making process, such as the reducing, melting, refining, this method is characterized in that the iron-making dust containing ≥0.1% volatile metal, such as Zn, is used as a desiliconizing agent or dephosphorizing agent, and collected dust generated at the desiliconizing time or dephosphorizing time and excessive dust which can not be used as the desiliconizing agent and dephosphorizing agent, is kneaded together with a carbonaceous material for reduction to form an aggregate, and reduced iron obtained by reducing this aggregate with an exclusive-use reducing furnace, is used as a steelmaking raw material, and the collection dust generated in the exclusive-use reducing furnace, is used as a non-ferrous raw material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a steelmaking method (electric furnace steelmaking method, cold iron source melting method, Cupla hot metal / converter steelmaking method, blast furnace / converter steelmaking method, etc.) in which the scrap mixing ratio in the main raw material is 1% or more. The present invention relates to a method for effectively utilizing iron-making dust generated from iron-making processes such as melting and scouring.

  As a method of utilizing Zn-containing iron-making dust generated in the iron-making process, for example, as disclosed in (1) Japanese Patent Publication No. 2-8002, Zn-containing dust is blown into a hot metal using a lance, and Zn oxide is oxidized. (2) Japanese Patent Laid-Open No. 9-25504 and Japanese Patent Laid-Open No. 8-333612, in which hot metal is reduced with Zn and C in the hot metal to separate Zn vapor and collected by a dust collector. As disclosed in Japanese Laid-Open Patent Publication No. 11-92812, a method of adding Zn-containing dust as a hot metal dephosphorizing agent to remove P in hot metal and concentrating and recovering Zn is disclosed. Thus, a method of concentrating and recovering Zn by repeatedly using Zn-containing dust in hot metal de-Si or converter, (4) As disclosed in JP 2000-45012 A, a melting-dedicated converter and scouring Carbonized material is agglomerated and agglomerated in dust generated in a dedicated converter, and reserved in a preliminary reduction furnace. A dust utilization method that is reused after reduction has been proposed.

However, the method (1) discloses the basic reaction of Zn enrichment, and no specific study has been made to apply this to an actual iron making process.
In addition, since the method (2) loses a great deal of heat when the Zn oxide reacts with C, Si and P in the hot metal, sensible heat and latent heat in the hot metal before the treatment are allowed. It was only a Zn-containing iron-making dust treatment method, and all the dust generated in the iron-making process could not be recycled.
The method of (3) is a method of concentrating and recovering Zn-containing dust to the level of valuable materials by repeatedly using Zn-containing dust to hot metal de-Si or converters, but repeatedly using Zn-containing dust. It has been unrealistic to manage the number of times and separate and collect for each repeated order, and it was difficult to implement.
In addition, the method (4) uses the pre-reduction furnace with a larger capacity than necessary in order to use all the dust generated in the steelmaking process. It was hard to say.
Japanese Patent Publication No. 2-8002 Japanese Patent Laid-Open No. 9-25504 JP-A-8-333612 Japanese Patent Laid-Open No. 11-92812 JP 2000-45012 A

The present invention solves the problems of the prior art as described above, and completely recycles the steelmaking dust generated from the steelmaking process such as reduction, dissolution, and scouring within the ironmaking process, thereby reducing zero emission of the steelmaking dust. It is an object of the present invention to provide an effective utilization method of steelmaking dust resources.
It is another object of the present invention to provide an effective utilization method of steelmaking dust resources that can minimize the required infrastructure scale by implementing an optimum dust treatment method according to the Zn content ratio among a plurality of steelworks.

The present invention has been made as a result of intensive studies in order to solve the above-mentioned problems, and by selecting an optimal treatment method according to the characteristics of dust generated in the iron making process, the iron making dust is completely removed within the iron making process. It is possible to achieve zero emissions of steelmaking dust, and to provide an effective method for recycling steelmaking dust that can minimize the scale of infrastructure required by multiple steelworks. However, the following contents are as described in the claims.
(1) Effective utilization of steelmaking dust generated in steelmaking processes such as reduction, dissolution, and smelting, and ironmaking dust containing 0.1% or more of volatile metals such as Zn is used to remove molten iron and remove P And agglomerates by kneading together dust collecting dust generated during the de-Si and de-P and surplus dust that cannot be used as the de-Si and de-P agent together with a reducing charcoal. A method for effectively utilizing iron-making dust, characterized by using reduced iron reduced in a dedicated reduction furnace as a steelmaking raw material, and using dust collection dust generated in the dedicated reduction furnace as a non-ferrous raw material.
(2) Effective use of iron dust generated in steelmaking processes such as reduction, melting, and smelting at multiple steelworks, and scrap that becomes a mixed source of volatile metals such as Zn at specific steelworks The ironmaking dust containing less than 0.1% of volatile metals such as Zn is used as sintering and blast furnace raw material, and the ironmaking dust containing 0.1% or more of volatile metals such as Zn is used as hot metal. The dust collection dust generated at the time of the de-Si and the de-P, and the surplus dust that cannot be used as the sintering and blast furnace raw material or the de-Si and de-P agent, together with the reducing charcoal Kneaded into agglomerates, reduced iron obtained by reducing the agglomerates in a dedicated reduction furnace is used as a steelmaking raw material, and dust collection dust generated in the dedicated reduction furnace is used as a non-ferrous raw material. Recycling of steelmaking dust How to use.
(3) Preferentially use iron-making dust with low volatile metal content such as Zn as hot metal de-Si and P removal agent, and preferentially use iron-making dust with high carbon content in a dedicated reduction furnace The method for effectively recycling resources of iron-making dust according to (1) or (2), characterized in that it is reduced and reused.

According to the present invention, there is provided a method for effectively utilizing steelmaking dust resources, in which ironmaking dust generated from ironmaking processes such as reduction, dissolution, and smelting is completely recycled within the ironmaking process, and zero-emission of ironmaking dust is realized. Can be provided.
In addition, it is possible to provide an effective utilization method of steelmaking dust that can minimize the required infrastructure scale by implementing an optimum dust treatment method according to the Zn content rate between a plurality of steelworks.
As for the accumulation of steel products in Japan, it is assumed that a large amount of iron scrap will be generated and accumulated when consumer materials such as building structures, automobiles and home appliances are scrapped down in the future.

On the other hand, high-function and high-value-added building structures, automobiles and home appliances, etc., that have been promoted so far, complicate the material composition, and scrap contains volatile non-ferrous metals such as Zn in addition to iron. Can no longer be avoided. Therefore, when steel companies recycle and use these scraps, it is essential to discharge volatile non-ferrous metals such as Zn outside the steelworks system and make them resources.
In addition, iron dust itself has been used effectively in the cement industry, but it has begun to be treated as waste with no use due to a decline in domestic cement demand.
INDUSTRIAL APPLICABILITY The present invention is an effective means for solving the problems in the previous period that steel companies will encounter in the future in such environmental changes, and has a remarkable industrially useful effect.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described in detail with reference to Example 1 and Example 2.

FIG. 1 is a diagram showing an embodiment in which the present invention is applied to a blast furnace integrated steelworks having a hot metal treatment facility and a dust reduction furnace for monthly crude steel production of 400,000 tons.
In FIG. 1, the ironmaking raw material supplied from the raw material yard 1 is processed into sintered pellets or the like in the raw material processing facility 2, reduced and melted in the blast furnace 3, and then removed by the hot metal treatment process 4. The P is removed and refined in the converter 5 to produce steel, and the generated iron-making dust is processed in the dedicated reduction furnace 6 as necessary.
The present invention provides a method for reusing and effectively utilizing each iron-making dust generated in the iron-making processes such as reduction, dissolution, and scouring.
Tables 1 to 3 show comparative examples in which the conventional dust treatment method is applied to the integrated blast furnace steelworks shown in FIG. 1, and Table 4 shows an example in which the steelmaking dust resource utilization method of the present invention is applied.

The ironmaking dust generated at the blast furnace integrated steelworks includes raw material dust such as sintering and pellet mills, blast furnace primary ash, and blast furnace dust collection dust that do not contain Zn or other volatile metals such as Zn. These can be reused as sintered and pellet raw materials.
In addition, blast furnace secondary ash and converter dust containing volatile metals such as Zn can be resource-reduced and volume-reduced.
First, Table 1 shows the case where the technology proposed in Japanese Patent Publication No. 2-8002, Japanese Patent Laid-Open No. 9-25504, Japanese Patent Laid-Open No. 8-333612 is applied to iron-making dust generated at a blast furnace integrated steelworks. Shown in Case 1).

In this comparative example, raw material dust and blast furnace dust with a Zn content of less than 0.1% are used as sintering and pellet raw materials, and fine converter dust and converter dust collection with a Zn content of 0.1% or more. Dust was used for hot metal treatment.
However, the amount that can be used as a hot metal de-Si agent or P agent is limited due to thermal restrictions. If the same amount is 20 kg / t, 16.5 kg / t of dust can be used in steelworks. Waste without any waste.

Next, Table 2 (Case 2) shows the case where the technique proposed in Japanese Patent Laid-Open No. 11-92812 is applied to steelmaking dust generated at the blast furnace integrated steelworks.
In this comparative example, raw material dust with a Zn content of less than 0.1% and blast furnace dust are used as sintering and pellet raw materials, and dust with a Zn content of 0.1% or more is used twice for hot metal treatment and converters. Used repeatedly.
As a result, the Zn content in the hot metal pretreatment dust and converter dust containing volatile metals such as Zn has been increased by repeated use in the converter with the desiliconizing agent or dephosphorizing agent of the hot metal, and in some cases non-ferrous refining raw materials However, the progress of Zn concentration also leads to an increase in the amount of dust generated, and as a result, when it is used repeatedly up to two times in reality, 5 kg / t of dust is treated as waste that is not used in steelworks. became.

Next, Table 3 (Case 3) shows the case where the technique proposed in Japanese Patent Application Laid-Open No. 2000-45012 is applied to steelmaking dust generated at the blast furnace integrated steelworks.
In this comparative example, raw material dust with a Zn content of less than 0.1% and blast furnace dust are used as sintering / pellet raw materials, and dust with a Zn content of 0.1% or more is processed in a dedicated reduction furnace. As a result, all of the ironmaking dust containing volatile metals such as Zn is reduced in a dedicated reduction furnace, and the reduced iron is used as a raw material for ironmaking. As a result, zero emission of dust generated in steel works can be achieved.
Here, the Zn content in the dust used as a sintering / pellet raw material is less than 0.1% because the sintering / pellet produced using dust containing 0.1% or more of Zn is charged into a blast furnace. This is because there is a risk that zinc oxide is deposited on the furnace wall in the blast furnace and the smooth lowering of the raw material is hindered due to the large amount of zinc.

However, the necessary processing capacity of the dedicated reduction furnace in this case 3 is 144 kt / M (= 36.1 k / t x 400 kt / M), and there is a problem that the equipment cost is high.
On the other hand, Table 4 (Case 4) shows a case where the technique proposed in the present invention is applied. In this example of the present invention, raw material dust having a Zn content of less than 0.1% and blast furnace dust are used as sintering / pellet raw materials, and the dust having a Zn content of 0.1% or more is once removed from the hot metal. By using it as a de-P agent, the volume of dust itself was reduced, and on that basis, excess dust that could not be applied to the hot metal de-Si agent or P agent was reduced in a dedicated reduction furnace.
As a result, not only can the dust generated in the steelworks be reduced to zero emissions, but the required processing capacity of the dedicated reduction furnace is 66 kt / M (= 16.5 k / t × 400 kt / M), which means that the scale of the facility is larger than that of Case 3. It was possible to suppress it to half or less.

Figure 2 shows an example in which the invention is applied to a total of three locations: two blast furnace integrated steelworks with a monthly crude steel production of 400,000 tons and one electric furnace with a monthly crude steel production of 50,000 tons Table 5 shows the dust treatment method.
The blast furnace integrated steelworks, which is A Steel Works, has only hot metal treatment equipment, and the blast furnace integrated steelworks, which is B Steel Works, has only a dedicated reduction furnace. Here, at steelworks A, the scrap that becomes the source of contamination of volatile metals such as Zn is controlled by the amount of Zn, and iron dust containing volatile metals such as Zn is secondary to the blast furnace except for hot metal pretreatment dust. Only ash and converter dust collection can be collected.
On the other hand, at the B and C steelworks, scraps containing volatile metals such as Zn, which are regulated at the A steelworks, are concentrated.

Table 5 shows specific dust treatment methods in this example of the present invention.
First, at A Works, raw material dust and blast furnace dust with Zn content of less than 0.1% are used as sintering and pellet raw materials at A Works, and converter dust collection dust with Zn content of 0.1% or more is used. It was used for hot metal treatment at the A steelworks, and the secondary ash of the blast furnace was treated in the special reduction furnace at the B steelworks.
Next, at B Steel Works, raw material dust and blast furnace dust with Zn content of less than 0.1% are used as sintering and pellet raw materials at B Steel Works, and converter dust collection dust with Zn content of 0.1% or more. Is used for the hot metal treatment at the A Works, and the secondary ash of the blast furnace is treated in the dedicated reduction furnace at the B Works, and the fine dust from the converter is treated with the hot metal treatment at the A Works and the dedicated reduction furnace at the B Works. It was shared.

In addition, the electric furnace dust collection dust at C Steel Works was used for hot metal treatment at A Steel Works.
As described above, after allocating scrap use containing volatile metals such as Zn among three locations, use iron-making dust with a volatile metal content such as Zn less than 0.1% as sintering and blast furnace raw materials, Zn etc. Steelmaking dust containing 0.1% or more of volatile metal is used as a hot metal de-Si and P-removing agent. This dust collection dust generated at the time of de-Si and de-P and the surplus dust that cannot be applied to sintering and blast furnace raw material and de-Si and de-P agent are kneaded together with a reducing charcoal and agglomerated and agglomerated in a dedicated reduction furnace Reduced, reduced iron is used as a raw material for steelmaking, and the dust collected in the reduction furnace can be sold outside as a non-ferrous refining raw material.
Here, among iron-making dusts containing 0.1% or more of volatile metals such as Zn, the effect of reducing the volume of dust is further demonstrated by using it as a de-Si and de-P agent for hot metal in preference to iron-making dust with a low Zn content. To do. In addition, among the steelmaking dust containing 0.1% or more of volatile metals such as Zn, the amount of carbonaceous material required for reduction is suppressed by using it in the dedicated reduction furnace in preference to the steelmaking dust with a high C content. Can do.

As a result of the above, all of the ironmaking dust generated from the three locations can be used as a raw material for steelmaking or non-ferrous refining. Hot metal pretreatment equipment used in volume reduction processing of steelmaking dust containing more than 10%, necessary processing capacity of dedicated reduction furnace that recycles steelmaking dust containing 0.1% or more of volatile metals such as Zn into ironmaking raw materials and non-ferrous raw materials, Equipment power can be minimized.

It is a figure which shows the Example at the time of applying this invention to the blast furnace integrated steelworks of the monthly crude steel production amount of 400,000 tons scale which has a hot metal processing equipment and a reduction furnace only for dust. The figure shows an example in which the invention is applied to a total of three locations: two blast furnace integrated steelworks with a monthly production capacity of 400,000 tons and one electric furnace steelworks with a monthly production capacity of 50,000 tons. is there.

Explanation of symbols

1 Raw material yard 2 Raw material processing equipment (sintering / pellet)
3 Blast furnace 4 Hot metal treatment 5 Converter 6 Dedicated reduction furnace (rotary hearth type reduction furnace)
7 Electric furnace

Claims (3)

  This is a method for effectively utilizing ironmaking dust generated in ironmaking processes such as reduction, dissolution, and smelting, and uses ironmaking dust containing 0.1% or more of volatile metals such as Zn as a hot metal removal Si and P removal agent. The dust collection dust generated at the time of de-Si and P removal and the surplus dust that cannot be used as the de-Si and P-removing agent are kneaded together with a reducing charcoal to form an agglomerate, and the agglomerate is exclusively reduced. A method for effectively utilizing iron-making dust, characterized by using reduced iron reduced in a furnace as a steelmaking raw material, and using dust collection dust generated in the dedicated reduction furnace as a non-ferrous raw material.   This is a method for effectively using steelmaking dust generated in steelmaking processes such as reduction, melting, and smelting at multiple steelworks, and regulations on the use of scrap that is a source of volatile metals such as Zn in certain steelworks In addition, iron-making dust with a volatile metal content such as Zn of less than 0.1% is used as a sintering and blast furnace raw material, and iron-making dust containing 0.1% or more of volatile metal such as Zn is removed from the hot metal. Used as a P-removing agent, and kneading dust collecting dust generated during de-Si and P-removing and surplus dust that cannot be used as sintering and blast furnace raw material or de-Si and P-removing agent together with a reducing carbonization agent. Using the reduced iron obtained by reducing the agglomerate in a dedicated reduction furnace as a steelmaking raw material, and using dust collection dust generated in the dedicated reduction furnace as a non-ferrous raw material. Effective use of dust resources Law.   Preferentially use iron-making dust with low content of volatile metals such as Zn as hot metal de-Si and de-P agent, and preferentially reduce iron-making dust with high carbon content in a dedicated reduction furnace. The method of effectively using resources of ironmaking dust according to claim 1 or 2, wherein the steelmaking dust is reused.

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