KR20150111488A - Method and equipment for compacting fe-containing by-products in molton irons making process - Google Patents

Abstract

The present invention relates to a byproduct solidifying method to solidify sludge containing dust and moisture which is a ferruginous byproduct generated in a molten iron producing process. The present invention provides the byproduct solidifying method comprising: a sludge drying step of drying some of the sludge or all the sludge; a byproduct mixing step of producing mixed byproduct containing a predetermined amount of moisture by mixing dust, dried sludge, and the remaining sludge; a solidifying step of producing the solidified byproduct by solidifying the mixed byproduct; and a solidified object drying step of obtaining a byproduct-solidified object by drying the solidified byproduct.

Description

TECHNICAL FIELD The present invention relates to a method and apparatus for producing iron-based byproducts from coal-based molten iron manufacturing processes,

The present invention relates to an efficient by-product compacting method and apparatus for recycling a by-product containing a large amount of an oil component generated in the form of dust or sludge in a coal-based molten iron manufacturing process in a compacting process of reduced iron.

The FINEX line manufacturing facility in the coal-based molten iron manufacturing process consists of a fluidized-bed reduction process for reducing iron ore in the mined state, a compacting process for making the reduced iron ore into a bulk state, and a coal- And a melting furnace process in which it is melted in a melting furnace. Depending on the characteristics of each process, a certain amount of by-products are discharged.

The discharged by-products are mainly composed of useful components directly used in a molten iron manufacturing process, such as iron ore, additives, and carbon-containing materials, and thus it is advantageous in terms of economics to be recycled in the molten iron manufacturing process. At this time, when the by-product is discharged using water, it is recovered in the form of sludge, and when water is not used, it is recovered in the form of dust.

However, in recycling the by-products recovered in the form of sludge as described above, since the sludge contains moisture, the sludge is not easily handled and can not be used immediately, so that the sludge can be recycled only by removing water by the pretreatment process. Accordingly, there is a problem that a large amount of energy is consumed in the process of removing moisture to recycle the by-product.

On the other hand, most of the recovered by-product particles have a particle size of less than 100 탆. Therefore, when they are used directly in a molten iron manufacturing process, they are most likely to be re-dispersed and lost. Therefore, in order to overcome the above-mentioned problem, it is compacted and then charged into a melting furnace process for recycling.

In the case of recycling by charging into the melting furnace process, the by-products of dust form do not need to be subjected to a drying process, and in case of sludge, the byproducts of each by-product are loaded after moisture is dried. However, since such compacted by-products are low in room temperature strength and hot strength, they are differentiated in the moment of being injected into a melting furnace that is differentiated during transportation or maintained at about 1,000 ° C. Since the differentiated particles are re-dispersed by the reducing gas generated in the melting furnace and are lost to dust or sludge again, the recycling effect is reduced by half. Further, when the differentiated particles remain in the melting furnace, There arises a problem that the air gap between the particles is filled to deteriorate the gas permeability.

In order to minimize the above problems, some methods have been proposed in which a binder is used to increase the bonding force between particles, or a heat treatment is performed at a high temperature similarly to the conventional pellet manufacturing process. However, energy consumption is increased, There is a problem that the recycling effect is reduced by half.

Due to the above-mentioned problems, recycling of by-products is limited in FINEX hot-wire manufacturing facilities, and most of the recovered by-products are supplied to cement plants free of charge and recycled or buried as iron sources. Therefore, it is necessary to minimize energy consumption for recycling of by-products, and technology development should be carried out in the direction of suppressing regeneration when becoming compact.

In general, FASTMET and Itmk3 are the typical processes for recycling sludge by-products, which are generated in the sintering process. All of these processes are the same as those of rotary kiln Dried using a drying device, compacted using a pelletizer, finally dried again and charged into a high-temperature rotary hose to produce reduced iron or steel nuggets. However, in this case, since the byproduct generation source and the treatment process exist separately, there is a problem that the investment cost for the by-product treatment is increased.

Therefore, it is required to improve the process for recycling by-products which can recycle by-products generated in the process of manufacturing molten iron such as FINEX in the process itself.

Accordingly, the present invention provides a new by-product compacting method in consideration of the amount of generated sludge and dust, particle size characteristics, moisture content, and the like, which are generated in a molten iron manufacturing process such as FINEX.

Also, a method for recycling a compacted material obtained by compacting in a molten iron manufacturing process is provided.

Further, it is intended to provide a compacting plant suitable for applying the compacting method.

The present invention relates to a by-product compacting method for compacting sludge containing dust and water as a by-product of iron ore generated in a molten iron manufacturing process, comprising: a sludge drying step of drying a part or all of the sludge; A by-product mixing step of mixing the dried sludge with dust and the remaining sludge to produce a mixed by-product having a predetermined moisture content; A compacting step of compacting the mixed by-products to produce compacted by-products; And a compacting step of drying the compacted byproduct to obtain a compacted compact.

The sludge drying step may further include dust together with the sludge.

The mixed byproduct may have a water content of 10 to 20% by weight based on the total weight of the mixed by-product, and the by-product may be thickened by stirring and mixing. At this time, stirring mixing can be performed by stirring at a stirring speed of 200 to 600 rpm for 1 to 30 minutes.

The compacting can be carried out by pelletizing the mixed by-products having a moisture content of 5-10% by weight. The mixed by-products having a moisture content of 10% by weight or less can be briquette-treated, 10 to 30% by weight of mixed by-products can be carried out by extrusion.

The dried byproduct compact may be performed so that the moisture content is less than 5 wt%. At this time, the by-product compact may be dried by a static drying method of a belt drier or a grate drying apparatus.

Further, after the drying step, it may further include a classifying and sorting step of sorting and sorting by-product compacts having a particle size of 1-10 mm.

The byproduct compacted material in the byproduct compacted material can be circulated to the by-product mixing stage, and the by-product compacted material of the granulated product can be pulverized and re-supplied to the classification and sorting step.

On the other hand, it is preferable that the selected by-product compact body has a particle size fraction of less than 1 mm in an amount of 50% or less.

The strength of the selected by-product compacted material is preferably 0.5 kgf or more on the basis of a 5 mm size compacted material.

The present invention also relates to a byproduct compacting apparatus for compacting sludge containing dust and moisture as a byproduct iron product generated in a molten iron manufacturing process, comprising a sludge drier for supplying the sludge through a pipe, ; A compacting facility for supplying the sludge dried by the sludge drier and the dust through respective pipes, mixing and compacting the sludge and the dust to produce compacted byproducts; And a compacted material drier for supplying a compacted byproduct produced in the compacting plant and removing water in the compacted byproduct to obtain a compacted compacted material.

The sludge dryer has a separate conduit through which the dust is supplied, and the sludge and dust are mixed and dried.

Wherein the compacting plant feeds the sludge containing the moisture through a separate piping and the sludge is mixed with the dried sludge and dust to produce compacted byproducts, It is possible to further include a pipe for injection. Further, the compacting equipment may be a stirring device, a briquetting device, a pelletizer or an extruder.

The compacted material drier may be a belt drier or a grate drier.

The iron and steel byproduct compacting apparatus may further include a classifier for classifying and sorting the size of the by-product compacted material and circulating fine or granulated by-product compacted material through a pipe to the compacting facility.

According to the present invention, byproducts can be compacted efficiently in the byproduct generation process in consideration of the generation amount of sludge and dust, the particle size characteristics, and the moisture content, which are byproducts generated in the process of manufacturing molten iron.

Therefore, by-products generated during the process can be recycled in the process, and the process efficiency for recycling by-products can be improved, and the investment cost required for recycling by-products can be reduced.

Fig. 1 is a flowchart schematically showing an example of a process for compacting sludge and dust which are by-products of molten iron manufacturing process.
2 is a flowchart schematically showing another example of a process for compacting by-product sludge and dust according to the present invention.

The generation rate of sludge and dust generated in the FINEX is about 8: 2 to 7: 3, and the amount of sludge generated is large. The moisture content of the sludge varies depending on the discharged position and components, to be. On the other hand, in the case of dust, some water is added in order to prevent it from being scattered when discharged, so that the dust contains a water content in the range of 15 wt% or less. The particle size of the sludge and dust is composed of a fraction of about 100 μm or less.

The present invention will now be described with reference to the accompanying drawings, in which a method for efficiently compacting sludge and dust having such characteristics is used.

As shown in FIGS. 1 and 2, the method of compacting iron-based byproducts according to the present invention includes a sludge drying step, a by-product mixing step, a compacting step and a compacting step drying step.

The present invention seeks to mass produce by-products generated in the process of manufacturing molten iron discharged from sludge and dust. At this time, the compacting can be performed by mixing sludge, which is a by-product, with dust, and then stirring at high speed.

However, the particle size of the product thus obtained and the apparent moisture content of the product are determined by the sludge of the stirring mixer and the total water content contained in the dust and the like. When the aggregation is carried out by the stirring as described above, The compacting of the particles can be most suitably carried out under the condition that the content is 10 to 20% by weight.

When the byproduct having a water content in the above range is used to compact the sludge, the sludge which maintains the lump shape is pulverized by stirring the mixed by-product of the sludge and the dust, and the water retained between the particles by the sludge is exposed It is possible to generate particles having a uniform size by being aggregated with the surrounding dust.

However, as described above, most of the by-products discharged during the molten iron manufacturing process are sludge containing moisture, and the water content is too large, so that they are not suitable for compacting by stirring. In addition, even if dust having a relatively low water content is mixed, there is a limit to control the water content to be suitable for compacting. When the water content is adjusted to a predetermined water content, the added dust content increases, but the amount of residual sludge increases , Which is undesirable in terms of recycling of the entire process by-products.

Accordingly, the present invention controls the moisture content by drying a part of the by-product to remove moisture, and then mixing with the by-product containing moisture, thereby aggravating the by-product by stirring the mixed by-product of the sludge and the moisture having controlled moisture content . On the other hand, in case of the dust 30, since the moisture content is less than the required moisture content, it can be directly supplied to the stirring mixer, thereby reducing the total moisture content.

For example, as shown in FIG. 1, only a part of the sludge 20 containing moisture is dried by a sludge dryer 240 to remove water contained in the sludge 20, 235, respectively. Subsequently, the sludge 20 and the dust 30 containing water can be supplied and mixed through the respective supply pipes so that the water content in the total by-product is in the range of 10 to 20 wt%, and by- You can make it big.

The sludge dryer 240 used for drying the sludge 20 may be a rotary kiln, a fluidized bed type, a belt type, or the like, though it is not particularly limited.

The compacting unit 235 is not particularly limited and may be suitably used in the present invention as long as it has stirring and mixing means capable of mixing and mixing the mixed by-products charged in the compacting unit 235. However, it is preferable that the stirring and mixing means is capable of providing a stirring speed in the range of 200 to 600 rpm, and more preferably in the range of 350 to 500 rpm. The agglomeration by the sludge 20 and the dust 30 can be achieved when stirring is carried out at the agitation speed within the above range.

On the other hand, the stirring time is not particularly limited, but can be carried out for 1 minute to 30 minutes. When stirring is performed for less than 1 minute, sufficient compacting is not achieved and the strength of the compacted material may be insufficient. On the other hand, when stirring is carried out for 30 minutes or more, the increase in the effect due to the additional stirring can not be obtained, which is uneconomical. For example, the by-product can be compacted by performing the treatment for 1 minute to 20 minutes, 2 minutes to 10 minutes, and 2 minutes to 6 minutes.

On the other hand, a pelletizer can be used for compacting by-products. However, when the pelletizer is compacted using the pelletizer, the water content of the by-product is preferably about 5-10% by weight. An example of a by-product compacting process in the case of using such a pelletizer is shown in FIG.

2, all of the sludge 20 supplied for compacting the byproducts is charged into the sludge dryer 240 and dried to remove moisture contained in the sludge 20, The water 30 is supplied to the pelletizer as the compacting unit 235 and mixed with the dust 30 to control the content of water contained in the total by-products used for compacting the by- .

In this case, when the pelletizer is used as described above, it is preferable that the moisture content is 5 to 10% by weight. Therefore, the sludge 20 is partially added to the sludge dryer 240 The moisture content of the by-product can be controlled by reducing the moisture content of the by-product and supplying the remaining dust 30 to the debossing facility 235.

On the other hand, a compacting unit 235 for compacting by-products by applying a predetermined pressure may be used. The compacting unit 235 by pressurization can be suitably used in the present invention without any particular limitations as long as it can pressurize the fine by-products by compressing them. For example, an extruder or a briquet (briquet) ) Device, and the like.

However, it is more preferable to appropriately adjust the water content included in the by-product in order to thicken the by-product in the above-described compacting plant. For example, when using a briquetting apparatus, it is preferable to use 10% by weight or less of water-reducing material, preferably a water-containing material having a water content of 10 to 30% by weight when an extruder is used desirable.

Although the detailed description of the case of compacting using pressurization compacting equipment is not specifically described, it will be understood by those skilled in the art that, according to the compacting equipment used with reference to FIGS. 1 and 2, It is possible to produce a by-product compacted product by suitably controlling the moisture content of the by-products used in the process.

As shown in Figs. 1 and 2, in order to increase the strength and recovery rate of the compacted compacted material, if necessary, additive such as water, a by-product having a different particle size, a binder, etc. 60 ). Further, in order to further increase the recycling efficiency of by-products, iron components, other by-products containing a large amount of carbon components, ores or coal may be added together.

In the embodiments of the present invention as described above, the moisture content of the byproduct compact obtained in the compacting step may vary depending on the manufacturing process, but includes moisture in the range of approximately 30% by weight or less. The byproduct irregular compact 90 obtained in the present invention can be used to produce reduced iron compacted irons by charging the reduced irons into a compacting step and mixing them with reduced iron.

In this case, when the water content of the byproduct compacted body 90 charged in the reduced iron compacting step is high, the reoxidation phenomenon of the reduced iron is increased by such moisture, and the problem of poor formability due to the generated gas . Thus, a drying step of drying the compacted by-products in the compacting step to obtain the by-product compacted material 90 from which moisture has been removed.

The drying is preferably carried out so that the water content in the by-product compacted material is 5 wt% or less. If the water content of the by-product compacted material exceeds 5% by weight, it may have an adverse effect of reducing the reduction ratio of the reduced iron by 1% or more. Therefore, the water content in the by-product compacted material is preferably at least less than 5%, more preferably, less.

The compacted material drier 245 used for drying the by-product compacted material is not particularly limited, and the same material as the sludge dryer 240 used for drying the sludge 20 may be used. However, since the byproduct compacted material 90 dried during the drying process of the byproduct compacted material may be differentiated, it is more preferable to use a belt type or a dynamic type dryer instead of using a dynamic dryer such as a rotary kiln or a fluidized bed type dryer in order to minimize such regeneration. It is more preferable to use a static dryer such as a grate type dryer.

According to each embodiment of the present invention, the by-product compacted material 90 can be manufactured from by-products such as sludge 20 and dust 30 discharged during a molten iron manufacturing process. Meanwhile, the produced byproduct compacted material 90 can be suitably used to prepare the compacted material by charging the compacted iron in the process of making the molten iron during compacting process and mixing the reduced compacted steel with the reduced iron.

As described above, it is preferable that the by-product compacted material 90 has a strength and particle size suitable for transportation during the reduced iron compacting process in order to use the compacted irons compact. The strength of the by-product compact body 90 has an intensity of 0.5 kgf or more based on 5 mm spherical particles, which minimizes the differentiation in the course of transportation and storage. For example, it is more preferable that the by-product compacts 90 have a strength of 1 kgf or more and 2 kgf or more.

On the other hand, the above-mentioned by-product compacted material is preferred from the viewpoint of preventing the differentiation during transport and storage as the strength is higher, and the upper limit of the strength is not particularly limited. However, the amount of energy consumed to obtain a high-strength byproduct compacted body is excessively demanded, which is not preferable for the process economy. In view of this, the strength may be, for example, 20 kgf or less, 10 kgf or less, 7 kgf or less, 5 kgf or less, or 3 kgf or less.

The particle size condition of the by-product compacted material 90 is not limited to this, but preferably has a particle size within the range of 1 to 10 mm. When the particle size of the by-product compacted material 90 is less than 1 mm, the formability is disadvantageously mixed when mixed with reduced iron. On the other hand, even if the by-product compacted material 90 having a size of less than 1 mm is contained, it is preferable that the content is less than 50% by weight in order to secure the moldability of the reduced-irregular compacted material. On the other hand, if it is more than 10 mm, it may not be smoothly transferred into the compacted irregularization process of the by-product compacted material.

Therefore, it is preferable that the by-product compacted material 90 is classified according to the particle size so that the by-product compacted material 90 having the particle size within the range is selected. For this purpose, the obtained by-product compact body 90 is classified and sorted through the classifier 250.

Furthermore, the byproduct irregular compacts 90 having the above-mentioned selected particle sizes classified by the classifier 250 can be preferably recycled by charging the reduced iron compacting process or the like as described above. On the other hand, the byproduct compacted material 95 having a particle size smaller than the above range can be circulated again to the compacting facilities 230 and 235, and the granulated by-product compacted material having a particle size exceeding the above range can be crushed by a crusher, The size of the byproduct compacted material 90 can be recycled.

Example

Hereinafter, the present invention will be described more specifically by way of examples. The following examples are illustrative of the present invention, but the present invention is not limited thereto.

Example  One

By-products are compacted by the process shown in Fig. 1 using sludge and dust generated in the process of manufacturing FINEX molten iron.

The sludge 20 having a moisture content of about 40 wt% and the dust 30 having a moisture content of about 15 wt% generated in the manufacturing process of the FINEX molten iron were respectively prepared and the byproducts prepared had a weight ratio of the sludge 20 and the dust 30 Was 7: 3.

Half of the total sludge 20 was charged into a sludge dryer (rotary kiln) 240 and heated to remove moisture.

The moisture-free sludge was supplied to the agitating mixer as the compacting unit 230, and the remaining sludge 20 was directly supplied to the agitating mixer without being dried and mixed with the dried sludge. Further, the dust 30 was supplied to the stirring mixer.

The water content in the by-products mixed in the stirring mixer was about 18% by weight of the total weight of water and by-products.

The above-mentioned stirring mixer was agitated at a stirring speed of 400 rpm for about 4 minutes at high speed to make by-products.

After the compacting, the by-product compacted material in the stirring mixer is transferred to the compacting material drier 245 to be completely dried, and the dried compacted material is separated into a byproduct compacted material 90 having a particle size in the range of 1-10 mm ) Were classified.

The content of the by-product compacted material (90) obtained was measured and found to be about 85% of the weight of the byproducts charged in the stirring mixer.

Further, the strength of the produced by-product compact was measured to be about 1 kgf.

Example  2

This is an example in which a by-product compacted material was produced by the process shown in Fig. 2 using sludge and dust generated in a FINEX molten iron manufacturing process.

By-products of the same process as in Example 1 were prepared.

The entire sludge 20 was charged into a sludge dryer (rotary kiln furnace) 240 and heated to remove moisture.

The dehydrated dried sludge was supplied to the pelletizer as the compacting equipment 30, and the dust 30 was also supplied to the pelletizer.

The moisture content in the by-products mixed in the pelletizer was about 5% by weight of the total weight of water and by-products.

Water was added to the pelletizer to adjust the moisture content of the by-product in the pelletizer to 8 wt%, and the by-product was made into pellets using a pelletizer.

After the compacting, the by-product compacted material in the pelletizer is transferred to the compacting material drier 245 to be completely dried, and the dried compacted material is separated into a byproduct compacted material having a particle size ranging from 1 to 10 mm 90) were classified.

The amount of byproducts obtained was measured and found to be about 95% of the byproduct weight supplied to the pelletizer.

The strength of the produced by-product compact was measured to be about 1.5 kgf.

20 Sludge
30 Dust
60 Additives
90 byproducts
95 fine-grained by-product compacted material
230, 235 Compacting plant
240 Sludge dryer
245 compact size dryer
250 minute supply

Claims (22)

As a by-product compacting method for compacting sludge containing dust and moisture as a by-product by-product generated in a molten iron manufacturing process,
A sludge drying step of drying a part or all of the sludge;
A byproduct mixing step of mixing the dried sludge with dust or dust and the remaining sludge to produce a mixed by-product having a predetermined moisture content;
A by-product compacting step of compacting the mixed by-product to produce a compacted by-product; And
And drying the compacted by-product to obtain a by-product compacted compact
By weight.
The method of claim 1, wherein the sludge drying step further comprises dusting with the sludge.
The method of claim 1, wherein the mixed by-product has a moisture content of 10 to 20 wt%.
4. The method of claim 3, wherein the compacting is performed by stirring mixing.
5. The method of claim 4, wherein the stirring is performed at a speed of 200 to 600 rpm for 1 to 30 minutes.
The method of claim 1, wherein the compacting is performed by pelletizing a mixed by-product having a moisture content of 5-10% by weight.
The method of claim 1, wherein the compacting is carried out by briquetting a mixed byproduct having a moisture content of 10% by weight or less.
The method of claim 1, wherein the compacting is performed by extruding a mixed by-product having a moisture content of 10 to 30% by weight.
The method of claim 1, wherein the by-product compact has a moisture content of less than 5 wt%.
The method of claim 1, wherein the compacting step is performed by a static drying method using a belt dryer or a grate dryer.
The method of claim 1, further comprising classifying and sorting the byproduct compacted material having a particle size of 1-10 mm after the drying step.
12. The method of claim 11, wherein the byproduct compact material in the by-product compact is circulated to the by-product mixing step.
12. The method according to claim 11, wherein the byproduct compacted material of the byproduct compacted material is crushed and re-supplied to the classification and sorting step.
The method according to claim 11, wherein the selected byproduct compacted body has a fraction of by-product compacted bodies having a particle size of less than 1 mm of 50% or less.
The method according to claim 11, wherein the selected byproduct compacted material has a strength of 0.5 kgf or more on a 5 mm particle size basis.
As a by-product compacting plant for compacting sludge containing dust and moisture as a by-product by-product generated in a molten iron manufacturing process,
A sludge drier for supplying the sludge through piping and drying the supplied sludge;
A compacting unit for mixing the sludge dried by the sludge drier and the dust through the respective pipes and mixing the compacted sludge, and compacting the compacted sludge to produce a compacted byproduct; And
A compacted material drier for supplying the compacted by-products and removing water in the compacted by-
By-product denitrification facility.
The desulfurization equipment according to claim 16, wherein the sludge dryer has a separate piping to which the dust is supplied, and the sludge and dust are mixed and dried.
17. The apparatus of claim 16, wherein the compacting plant is a stirring device, a briquetting device, a pelletizer, or an extruder.
17. The method of claim 16, wherein the compacting plant feeds the water containing sludge via separate piping and the sludge is mixed with the dried sludge and dust to produce compacted byproducts, Equipment.
17. The iron-based by-product denitrification apparatus of claim 16, wherein the compacting plant further comprises a pipe for injecting an additive.
17. The apparatus of claim 16, wherein the compacted body dryer is a belt dryer or a grate dryer.
17. The method according to claim 16, wherein the by-product compacting plant further comprises a classifier for classifying and sorting the size of the by-product compacted material and circulating the fine-granulated or granulated by-product compacted material through a pipe to the compacting facility, .

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