JP5103802B2 - Method for treating wet dust and method for producing sintered ore - Google Patents

Description

  The present invention relates to a method for treating sludge-like wet dust collected from a wet dust collector into a sintered raw material, and wet dust and dry dust collected from each wet and dry dust collector as part of the sintered raw material. The present invention relates to a method for producing sintered ore.

In the steel manufacturing process, metal-containing dust is recovered from exhaust gas generated in various steps and reused as a sintering raw material or a raw material for smelting reduction. Among them, converter dust with high Cr content (hereinafter referred to as “high Cr-containing OG dust”) generated in the chrome ore smelting reduction process is smelted and reduced in a smelting reduction furnace as described below to obtain high Cr hot metal. Is manufactured.
This smelting reduction furnace is a vertical furnace in which a carbon-based solid reducing material such as coke is filled in the furnace, and tuyere is provided in multiple stages (usually two stages above and below) in the furnace height direction, and the upper wing Powdered raw materials (for example, high Cr-containing OG dust) are blown together with hot air or oxygen-enriched hot air from the mouth, and hot air or oxygen-enriched hot air is blown from the lower tuyere. In this smelting reduction furnace, the raw material blown from the upper tuyere is softened and melted at the tuyere, until the tuyere and the tuyere of the lower tuyere and further dropped as a melt on the hearth. In this process, the carbon-based solid reducing material is directly reduced (for example, Patent Document 1).

By the way, in the chrome ore smelting reduction process in which high Cr content OG dust is generated, a large amount of carbon material is used as a reducing material, and therefore, the high Cr content OG dust contains carbon material at a considerable concentration. When this high Cr-containing OG dust is blown into the smelting reduction furnace as described above, since there is no cohesive zone like the blast furnace in the furnace, a considerable amount of the carbonaceous material in the blown dust blows through the top of the furnace. , Discharged along with the furnace exhaust gas. The furnace exhaust gas is primarily dust-removed by a dry dust collector such as a cyclone and further dust-removed by a wet dust collector, and dry dust and wet dust are recovered from each, but these dusts contain a large amount of the above-mentioned carbonaceous materials, The carbon content will be quite high.
Japanese Patent Publication No. 2-42884

The sludge-like wet dust collected from the wet dust collector is dehydrated by a filter press dehydrator or the like to be dehydrated cake. Since this wet dust contains about 20 mass% of iron, it can be reused as a sintering raw material. However, since this wet dust has a fairly high carbon content, when it is charged into a sintering machine pallet with a dehydrated cake having a large particle size, a large thermal deviation occurs in the charged raw material, so-called uneven burning can occur. It adversely affects the quality of sintered ore. In addition, even if the dehydrated cake is crushed, it contains 40 mass% or more of moisture, so that the handling property is bad. Therefore, it is difficult to simply load the dehydrated cake into the sintering machine pallet as it is, Even if it can be charged, problems similar to those described above are likely to occur.
In addition to the wet dust as described above, for example, even if the dust is relatively low in carbon content, if it is charged as a sintering raw material into a sintering machine pallet as a dehydrated cake, Heat deviation is likely to occur in the raw material, and it is likely to cause uneven burning of the sintered ore.

Accordingly, an object of the present invention is to solve the above-described problems of the prior art and to provide a treatment method capable of treating wet dust recovered from a wet dust collector in a suitable state as a sintering raw material.
In addition, another object of the present invention is to provide a method for producing sintered ore that can produce sintered ore using wet dust and dry dust recovered from wet and dry dust collectors as part of the sintering raw material. There is to do.

The features of the present invention for solving the above-described problems are as follows.
[1] Sludge-like wet dust collected from the wet dust collector is dehydrated to obtain a dehydrated cake containing water of 40 mass% or more. After the dehydrated cake is crushed , dry dust and a binder are added and mixed and prepared. It is a wet dust treatment method to obtain a dust granulated material as a sintering raw material by granulating ,
The dry dust and the binder are added to the crushed dehydrated cake so that the water content of the mixture after mixing with the crushed dehydrated cake is 18 to 28 mass%, and the blending of the binder in the mixture The processing method of the wet dust characterized by the amount being 5-10 mass% .
[2] In the processing method of [1] , when the sludge-like wet dust recovered from the wet dust collector in a facility having a dry dust collector and a wet dust collector in the gas flow path is processed, the dust is recovered from the dry dust collector. A method for treating wet dust, characterized by adding dry dust.
[3] In the processing method of [2] , at least a part of each of the wet dust and the dry dust is used to produce hot metal using converter dust generated in the smelting reduction process of chromium ore as at least a part of the raw material. A method for treating wet dust, wherein the wet dust is collected from an exhaust gas dust collector of a smelting reduction furnace.

[4] Sludge-like wet dust collected from the wet dust collector is dehydrated to obtain a dehydrated cake containing water of 40 mass% or more. After the dehydrated cake is crushed , dry dust and a binder are added to mix and produce A method for producing a sintered ore by forming a dust granulated product by granulating, and producing a sintered ore using the dust granulated product as a part of a sintering raw material ,
The dry dust and the binder are added to the crushed dehydrated cake so that the water content of the mixture after mixing with the crushed dehydrated cake is 18 to 28 mass%, and the blending of the binder in the mixture The manufacturing method of the sintered ore characterized by the amount being 5-10 mass% .
[5] In the manufacturing method of [4] above, the dust granulated material is transferred from the other conveyor to the sintered raw material being conveyed by the conveyor, and the sintered raw material and the dust granulated material are simultaneously sintered. A method for producing a sintered ore characterized by being supplied to a feed hopper.
[6] In the manufacturing method according to [4] or [5] , when using the sludge-like wet dust collected from the wet dust collector in a facility having a dry dust collector and a wet dust collector in a gas flow path, the dry dust collector A method for producing a sintered ore characterized by adding dry dust recovered from the sinter.
[7] In the manufacturing method of [6] , at least a part of each of the wet dust and the dry dust is used to produce hot metal using converter dust generated in the smelting reduction process of chromium ore as at least a part of the raw material. A method for producing a sintered ore characterized by being recovered from an exhaust gas dust collector of a smelting reduction furnace.
In the present invention, the dust granulated material is a mixture of pulverized wet dust and dry dust added to the pulverized wet dust that undergoes a granulating action such as agitation and rolling to produce pseudo particles. Point to.

According to the wet dust processing method of the present invention, wet dust recovered from a wet dust collector can be processed into a dust granule suitable as a sintering raw material.
Further, according to the method for producing sintered ore of the present invention, a dust granule suitable as a sintering raw material is produced using wet dust and dry dust recovered from wet and dry dust collectors, and this is sintered. Sinter can be produced as part of the raw material.

  In the wet dust treatment method of the present invention, the sludge-like wet dust collected from the wet dust collector is dehydrated to form a dehydrated cake, the dehydrated cake is crushed, and dry dust is added to mix and granulate. As a result, a dust granulated material to be a sintering raw material is obtained. In addition, the method for producing a sintered ore of the present invention involves dehydrating sludge-like wet dust collected from a wet dust collector to form a dehydrated cake, crushing the dehydrated cake, and adding dry dust to mix and prepare A granulated dust product is formed by granulating, and a sintered ore is produced using the dust granulated product as a part of a sintering raw material. Further, in such a treatment method and manufacturing method, when processing sludge-like wet dust collected from the wet dust collector in a facility having a dry dust collector and a wet dust collector in the gas flow path or using as raw materials, If the dry dust recovered from the dry dust collector is added to the wet dust, both the wet dust and the dry dust recovered in one furnace facility can be used. Is advantageous.

FIG. 1 shows a flow of an embodiment of a wet dust treatment method and a sintered ore production method of the present invention, in which converter dust (hereinafter referred to as “high” Cr content) generated in a chrome ore smelting reduction process is shown. , "High Cr-containing OG dust"), and wet dust collected from an exhaust gas dust collector of a vertical smelting reduction furnace that produces hot metal using a raw material as a raw material.
In the figure, 1 is a vertical smelting reduction furnace, 2 is an exhaust gas conduit of the vertical smelting reduction furnace 1, 3 is a dry dust collector (cyclone) provided in the exhaust gas conduit 2, and 4 is a wet dust collector provided on the downstream side thereof. It is.

  The vertical smelting reduction furnace 1 is a vertical furnace in which a carbon-based solid reducing material such as coke is filled in a furnace, and is disposed at a position near the lower part of the furnace at intervals in the furnace circumferential direction. The tuyere groups 5a and 5b made of tuyere are provided in two upper and lower stages, and high Cr-containing OG dust is blown together with hot air or oxygen-enriched hot air from the upper tuyere group 5a, and hot air or It blows oxygen-enriched hot air. The lower tuyere group 5b is provided mainly for the purpose of promoting the reduction of the raw material.

In such a vertical smelting reduction furnace 1, the furnace filling (carbon-based solid reducing material, etc.) is charged into the furnace from the top of the furnace. The high Cr content OG dust blown from the upper tuyere group 5a is softened and melted at the tip of the tuyere, the tuyere tip of the tuyere tip and the lower tuyere group 5b, and further the hearth as a melt. It is directly reduced by the carbon-based solid reducing material in the process until dripping. The molten material that has dropped and reaches the hearth is discharged out of the furnace as hot metal.
In addition, the tuyere group 5 may be provided in three or more stages in the furnace height direction. In this case, high Cr-containing OG dust is blown from the upper stage side one stage or two or more stage tuyere groups 5a. Done.

The gas generated in the vertical smelting reduction furnace 1 is guided to the exhaust gas conduit 2, and after primary dust removal by the dry dust collector 3, secondary dust removal is performed by the wet dust collector 4. The dry dust collected from the dry dust collector 3 is stored in the hopper 6a. The sludge-like wet dust collected from the wet dust collector 4 is precipitated by the thickener 7 and then dehydrated by a dehydrator 8 such as a filter press dehydrator to form a dehydrated cake.
The dehydrated cake-formed wet dust is supplied to the crushing and granulating apparatus 9. In this pulverization / granulation processing apparatus 9, the dehydrated cake is crushed, and dry dust is added and mixed / granulated to obtain a dust granulated material (wet dust, dry dust, etc.) as a sintering raw material. A pseudoparticle of the mixture).

Since moist dust contains 40 mass% or more of moisture even after being dehydrated, granulation is difficult if the dehydrated cake is crushed, and granulation is difficult. For this reason, moisture is adjusted by adding dry dust. Do. The dry dust may be of any type as long as it can be used as a sintering raw material. In this embodiment, dry dust collected from the dry dust collector 3 and stored in the hopper 6a is used. Is supplied from the hopper 6a to the crushing and granulating apparatus 9. If dry dust collected in the same exhaust gas flow path as wet dust is used in this way, it is advantageous in terms of effective use of dust and processing efficiency.
In addition, as other dry dust, 1 type, or 2 or more types, such as sintering dust collection dust, steel-making dust collection dust, blast furnace dust collection dust, can be used. The blast furnace dust collection dust includes dust collected from the exhaust gas from the top of the blast furnace and dust collected on the blast furnace casting floor, and both can be used.

In addition, when the amount of dry dust collected from the dry dust collector 3 is insufficient, dry dust collected in other processes (for example, steelmaking dust collection dust, sintered dust collection dust, blast furnace dust collection dust 1 Seeds or two or more) is supplied from the hopper 6b to the crushing and granulating apparatus 9.
Moreover, in order to obtain a suitable dust granulated material, it is preferable to mix | blend a binder in addition to the said dry dust. For this reason, a binder is supplied to the crushing / granulating apparatus 9 from the hopper 6c as needed. As this binder, 1 type (s) or 2 or more types, such as quick lime, cement, slaked lime, can be used, for example.

  In the pulverization / granulation processing device 9, the action of pulverizing the dehydrated cake of wet dust and the action of mixing and granulating the wet dust with dry dust (and a binder if necessary) added to it. Finally, a dust granulated product is obtained. The crushing / granulating device 9 for realizing such two actions may be one in which crushing and mixing / granulation are performed substantially in one device (space), Crushing and mixing / granulation may be performed in separate apparatuses (spaces). As the former device, for example, a device that performs batch crushing and mixing / granulation of dust with one rotating stirring means, or a crushing means and mixing / granulating means in one device (space). There is a batch type device for crushing, mixing and granulating dust. As the latter apparatus, for example, a crushing means (for example, a stirring type crusher) is provided in the former stage, and a mixing / granulating means (for example, a mixing granulator or a rolling granulator) is provided in the latter stage. There is an apparatus that sequentially performs a dust crushing process and a mixing / granulating process in batch or continuous mode.

In the processing by the pulverization / granulation processing device 9, the timing of adding dry dust or binder to the wet dust is arbitrary, and may be added before or during the pulverization of the wet dust. From the viewpoint of granulation, it is preferable to add after crushing wet dust.
The amount of dry dust added to the wet dust is appropriately selected according to the amount of moisture in the wet dust so that the raw material mixture can be granulated, but dry dust etc. are mixed from the viewpoint of granulation. It is preferable to add so that the water content as a mixture after being about 18 to 28 mass%. Normally, the moisture content of the dehydrated cake of wet dust is about 40 to 50 mass%, so generally the amount of dry dust added (when a binder is added, the amount of additive containing the binder) is [wet dust (including moisture). )] / [Dry dust (including binder)], the mass ratio is suitably about 36/64 to 70/30.

There is no special restriction | limiting in addition amount of a binder, Although it considers granulation property and it selects suitably, generally about 0-10 mass% is suitable.
The particle size distribution of the dust granulated material is not particularly limited, but preferably a particle size distribution in which the ratio of the particle size of 2 to 8 mm is 80 mass% or more is appropriate.
The dust granulated material obtained by the crushing / granulating device 9 is conveyed to a sintering plant in a transporting container 10 suitable as a sintering raw material, and receives a receiving hopper 11, a storage hopper 12, and a sintering feed hopper 13. Are sequentially fed to the sintering machine pallet 15 together with other sintering raw materials from the supply feeder 14 to produce sintered ore. In addition, 18 is a conveyance conveyor which connects between each hopper.

  FIG. 2 shows an embodiment for supplying the dust granulate to the sintering feed hopper 13, and 16 is the same for supplying the main sintering raw material X into the sintering feed hopper 13. It is the shuttle conveyor arrange | positioned so that a movement above a hopper is possible. In this embodiment, the dust granulated material Y is transferred from the other conveyor 17 onto the sintered raw material X being transported by the shuttle conveyor 16, and the sintered raw material X and the dust granulated material Y are simultaneously sintered. The feed hopper 13 is supplied. Thereby, the dust granulated material Y is charged into the sintering machine pallet 15 in a state where the dust granulated material Y is appropriately mixed with the sintering raw material X.

The wet dust to be processed or raw material in the present invention is that of the above embodiment, that is, vertical melting that produces hot metal using converter dust generated in the smelting reduction process of chromium ore as at least a part of the raw material. It is not limited to wet dust recovered from the exhaust gas dust collector of the reduction furnace. Therefore, various kinds of wet dust generated in the steel manufacturing process and other metal manufacturing processes can be targeted.
Examples of what is generated in the steel manufacturing process include converter dust, blast furnace wet dust, and the like, including the wet dust of the above-described embodiment, or one or more of these wet dusts to be processed or It can be used as a raw material.

Dust granulated material that becomes a sintering raw material after dewatering the wet dust collected from the dust collector of the furnace exhaust gas with a filter press, crushing the dehydrated cake, adding dry dust and binder, mixing and granulating Manufactured. The following were used as wet dust and dry dust.
(1) Wet dust Dust A: Vertical smelting reduction furnace that produces high Cr hot metal from the converter dust (C: 12 mass%, Fe: 57 mass%, Cr: 9 mass%) generated in the smelting reduction process of chromium ore Collected from the wet dust collector in the exhaust gas passage (C: 14 mass%, Fe: 18 mass%, Cr: 3 mass%)
Dust B: Blast furnace wet dust (C: 18 mass%, Fe: 42 mass%, Cr: 0 mass%)

(2) Dry dust Dust a: Vertical smelting reduction furnace that produces high Cr hot metal using raw material from converter dust (C: 12 mass%, Fe: 57 mass%, Cr: 9 mass%) generated in the chrome ore smelting reduction process Collected from the dry dust collector in the exhaust gas passage (C: 67 mass%, Fe: 11 mass%, Cr: 1.4 mass%)
Dust b: Sintered dust collection dust (C: 2 mass%, Fe: 47 mass%, Cr: 0 mass%)
Table 1 shows the treatment / manufacturing conditions in each example (wet dust, dry dust, binder type and blending amount, etc.) and the structure of the obtained dust granulated product.

Explanatory drawing which shows the flow of one Embodiment of the processing method of the wet dust of this invention, and the manufacturing method of a sintered ore. Explanatory drawing which shows one Embodiment in the case of supplying the dust granulated material obtained in this invention to a sintering feed hopper

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vertical smelting reduction furnace 2 Exhaust gas conduit 3 Dry type dust collector 4 Wet dust collector 5a, 5b Tuyere group 6a, 6b, 6c Hopper 7 Thickener 8 Dehydrator 9 Disintegration / granulation processing device 10 Transport container 11 Receiving hopper 12 Storage hopper 13 Sintering Feeding Hopper 14 Feeding Feeder 15 Sinter Pallet 16 Shuttle Conveyor 17, 18 Transport Conveyor X Sintering Raw Material Y Dust Granulated Material

Claims (7)

Sludge-like wet dust collected from a wet dust collector is dehydrated to obtain a dehydrated cake containing 40 mass% or more of moisture, and after the dehydrated cake is crushed , dry dust and a binder are added and mixed and granulated. Is a method of treating wet dust to obtain a dust granulated material as a sintering raw material ,
The dry dust and the binder are added to the crushed dehydrated cake so that the water content of the mixture after mixing with the crushed dehydrated cake is 18 to 28 mass%, and the blending of the binder in the mixture The processing method of the wet dust characterized by the amount being 5-10 mass% . The dry dust collected from the dry dust collector is added when processing the sludge-like wet dust collected from the wet dust collector in a facility having a dry dust collector and a wet dust collector in a gas flow path. 2. A method for treating wet dust according to 1 . At least a part of each of wet and dry dust recovered from the exhaust gas dust collector of a vertical smelting reduction furnace that produces hot metal using at least part of the raw material from the converter dust generated in the chrome ore smelting reduction process The method for treating wet dust according to claim 2 , wherein: Sludge-like wet dust collected from a wet dust collector is dehydrated to obtain a dehydrated cake containing 40 mass% or more of moisture, and after the dehydrated cake is crushed , dry dust and a binder are added and mixed and granulated. A method for producing a sintered ore by forming a dust granulated material by using the dust granulated material as a part of a sintered raw material ,
The dry dust and the binder are added to the crushed dehydrated cake so that the water content of the mixture after mixing with the crushed dehydrated cake is 18 to 28 mass%, and the blending of the binder in the mixture The manufacturing method of the sintered ore characterized by the amount being 5-10 mass% . It is characterized in that the dust granulated material is transferred from the other conveying conveyor onto the sintered raw material being conveyed by the conveyor, and the sintered raw material and the dust granulated material are simultaneously supplied to the sintering feed hopper. The manufacturing method of the sintered ore of Claim 4. Claim when using sludge-like wet dust recovered from the wet dust collector in facilities having a dry dust collector and a wet dust collector the gas flow path, and wherein the addition of dry dust recovered from the dry dust collector 4 Or the manufacturing method of the sintered ore of 5 . At least a part of each of wet and dry dust recovered from the exhaust gas dust collector of a vertical smelting reduction furnace that produces hot metal using at least part of the raw material from the converter dust generated in the chrome ore smelting reduction process The method for producing a sintered ore according to claim 6 , wherein:

Images