KR20050062511A - Method and apparatus for hot granulating metal-containing substance particles, such as sponge iron, metallurgical dusts, metallurgical residues, etc - Google Patents

Abstract

The present invention relates to a method for compressing metal-containing material particles such as sponge iron, metallurgical dust, metallurgical residues and the like to a high temperature, and apparatus for producing molten iron. The above method is intended to simplify the subsequent processing of fine particulate matter and / or pyrophoric materials in metallurgical plant equipment or steel processing. The method of the present invention provides a process for supplying hot material particles to a roller press, a process for producing a continuous elongated strip plate with the roller press, and a process for making the strip plate into powder and coarse granules (assembly). It is made to include.

Description

METHOD AND APPARATUS FOR HOT GRANULATING METAL-CONTAINING SUBSTANCE PARTICLES, SUCH AS SPONGE IRON, METALLURGICAL DUSTS, METALLURGICAL RESIDUES, ETC}

The present invention relates to a method for hot granulating metal-containing material particles such as sponge iron, metallurgical dust, metallurgical residues, and the like, and thus apparatus for producing molten iron.

There are already a number of methods according to the prior art for carrying out certain subsequent treatments (dissolutions) of metallurgical residues or directly reduced sponge iron. Most of these materials exist in the form of powders or fine powders and have therefore been treated in a very undesirable manner for many industrial applications. In addition, they are often pyrophoric, as well as strict restrictions regarding their storage and transportation. For example, in order to ship sponges, these materials must be pressed into briquettes (small lumps such as briquettes) that have been surface passivated to a predetermined density. This briquette system has two oppositely acting briquette rollers, each of which has molding pockets on its surface. The briquette rollers are thus coupled to each other such that the two molding pockets are in contact with each other while the remaining web-shaped portion remaining between the briquette pockets is very tightly compressed. After leaving the briquette rollers, this in turn results in an almost automatic separation of the briquettes. The risk of fire during storage and shipping is minimized due to the passivation treatment on the surfaces of the briquettes as well as the sufficient compression and reduction of the pores and the volume on which they are formed. This method has the problem that, among other things, briquette rollers are very complicated to manufacture and are particularly susceptible to excessive wear in the mesh portion. Moreover, one must take into account the fact that a certain amount of material must be followed up relatively immediately after a period of temporary storage at the plant, either directly or for a short time, so that no further storage or shipment is necessarily made.

It is therefore an object of the present invention, metals such as sponge iron, metallurgical dust, metallurgical residues and the like, which can be carried out in an easier manner as well as having a lower wear resistance to the compression apparatus used. The present invention provides a method and a manufacturing apparatus for hot-compacting a containing material particle at a high temperature.

In order to achieve the above object, the manufacturing method according to the present invention is:

Supplying hot material particles to a roller press;

Producing a continuously elongated strip plate by the roller press; And

Grinding the strip plate to produce relatively coarse particles (granules).

Also according to another aspect of the present invention,

An apparatus for producing molten iron is provided, the manufacturing apparatus of which

A feeder (feeder) for inserting metal-containing material particles such as sponge iron, metal dust, metallurgical residues, and the like;

A roller press configured to produce a continuous strip plate by feeding the substance particles under a roller pressing action;

A pulverizer for pulverizing the continuous strip plate to produce granulated material (granule); And

It comprises a supply means for supplying the granulated material as a raw material for steel production or injecting the granulated material into the melting furnace.

According to the method described above, continuous strips of the material particles are mainly produced using the ductility of the material at high temperatures and the resulting binding action of the metal particles (especially iron particles). The strip can extend over the entire width of the roller press, and preferably has a thickness that sufficiently compresses inside the plate. Until now, it has been common to briquette such materials. Direct follow-up processes in metallurgical plants or steel mills do not require homogeneous lump sizes, passivated surfaces or high minimum densities. The powdered material should be agglomerated so that it can enter the melt in a subsequent process and descend in the melt. This has been found by the inventor who proposed a method of using a simple roller press. Such roller presses may be exposed to greater wear than with briquette presses. If the intended density is made, a suitable feeder becomes very important here. The lifetime of metallurgical devices is significantly increased by using simple roller shapes. For example, if the barbed iron is to be processed on-site, it is granulated (coarse) in response to the required amount and fed to subsequent processing. Therefore, storage and shipping are not necessary, which is why the corresponding restrictions do not need to be applied.

It should be noted that a continuous strip plate is produced due to the properties of the metal-containing material particles without the addition of a fixative (adhesive). This method is different in the method of granulation with respect to the output without the above adhesive properties. Moreover, other granulation methods are carried out at low (cooled) conditions. The material particles are passed through a roller press at high temperature for excellent expression of adhesive properties. Such properties are typically obtained at 450 ° C. to 900 ° C., preferably at 600 ° C. to 700 ° C., in order to obtain adequate ductility as well as adequate adhesion properties of the metal-containing particles. For example, the compression temperature of the sponge iron by the reduction of fine ore can be 600 to 720 ℃, in the case of metallurgical dust or directly reduced ore in a rotary hearth (700 ℃), and also For metallurgical residues in rotary tubular furnaces it may correspond to 500 to 600 ° C.

Moreover, the density of the coarse particles will be less than 5 g / cm 3, preferably at least 3 g / cm 3 and less than 5 g / cm 3. Particularly in the case of granulating dust according to sponge iron or metallurgy, a density of between 3 g / cm 3 and 5 g / cm 3 is preferred depending on the quality of the feed material. Thus, the above assemblies mostly have a smaller density than in the case of similar materials according to the briquette method. In exceptional cases such assembly may also be produced at increased densities, for example less than 6 g / cm 3 or less than 7 g / cm 3. In some cases, especially for hot iron, it may have a density of less than 4.5 g / cm 3.

Preferably, the strip plate may be made of roller nips in the range of 5 mm to 40 mm, preferably 10 mm to 30 mm. An essential difference between compression and briquetting methods for the formation of assemblies is that in the case of compression for assembly, no significant web-shaped parts (on wear) are produced. Thus a relatively large nip or roller length is used. The preferred mass size in the compression process for the production of granulated material depends largely on the manner in which the material is subsequently processed. When the LD dust is treated, for example, for the converter, it is preferable that the particle size is larger than 10 mm.

Although it is possible to compress with a smooth roller in the basic form, in order to improve the feeding characteristics of the roller press, the roller press forms a profile on both main sides of the strip plate. You may. However, the above profile would have to be large enough to carry out an improved supply as desired. This also helps to form a predetermined breaking point that reduces the application of the force to produce the granulated material by grinding the strip plate described above.

In contrast to the Briquette scheme, in which the mold pockets are brought into contact with each other in a manner that fits substantially accurately, one variant of the invention, having improved feed properties and configured to form the desired desired breakpoint, Profiles having the same shape and pitch, but offset axially and radially with respect to each other, disposed on the major side. Despite the formation of this profile, the above method results in a more uniform compression. Different shaped profiles may be obtained by an inclined arrangement with respect to the roller axes.

Preferably, the strip plate may be ground to coarse particles (assembled) by grinding the strip plate to irregular particle size. This method is primarily aimed at producing particles of a certain density. Based on the production of steel by incorporating granulated iron into the steel melting furnace, this means that the particles must have a density that allows them to be dropped into the melting furnace. The size of the granulated particles must of course reach a minimum, but it is clear that the same size as the briquettes used previously is not necessary. Preferably, particles of different sizes across the entire range can be produced at one time and used in the same subsequent method (process).

By crushing the strip plate and subsequently supplying the crushed pieces or pieces to the impact grinder, the strip plate can be crushed into a granulated material having an irregular particle size. This distributes the energy needed for granulation, allowing each system to operate more efficiently and no longer under excessively heavy loads.

Hot material particles may be supplied by a screw feeder means to achieve a constant pre-compaction of the material particles and increase the yield by providing pressure in advance. This not only makes it possible to significantly avoid the incorporation of large amounts of gas during the feed, but also results in a more uniform plate strip.

Moreover, the size of the granulated material may be made uniform in a predetermined range. Screening systems as well as post-granulation or recycling to previous milling processes are particularly suitable here, so that only coarse particles having a predetermined size can be produced.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The method described herein with reference to the drawings and the apparatus used therefor are particularly suitable for treating metal-containing material particles. These may be, for example, sponge iron or metallurgical residues having metallic bonding properties and exhibiting plastic properties at elevated temperatures. For simplicity of explanation, only the sponge iron will be referred to as a material in the following description. The material is highly pyrophoric so that special restrictions exist especially with regard to its storage and shipping and must be normally observed.

The roller press 1 shown schematically in FIG. 1 includes two oppositely acting press rollers 2 and 3, between which a press nip portion 4 is formed. The press nip 4 described above is formed substantially the same over the entire length. The sponge iron particles 5 are supplied to the roller nip 4 through the gravity feeder 6. They are supplied in high temperature form, in particular the sponges being pressed at elevated temperatures which ensure some ductility and release the binding of the material particles. Thus strip plate 7 is made, which extends substantially over the entire length of press rollers 2 and 3. Thanks to the ductile properties of the spongy iron particles 5 they are bonded together without the addition of a binder. The roller nip 4 is usually at least 5 mm, preferably at least about 10 mm. In many cases roller nips of up to 10-30 mm are used. The temperature of the sponge iron particles 5 supplied is preferably 600-720 ° C. Depending on the material to be compressed, high temperature compression in the range of 450-900 ° C. is carried out. For example, the temperature is 700-900 ° C. for direct reduced iron or metallurgical dust in a rotary hearth and 500-600 ° C. for metallurgical residues in a tubular furnace. to be.

Subsequently, the mill 8 is supplied with the strip plate 7 described above. According to Fig. 1, the mill 8 comprises two oppositely driven mill rollers 9 and 10, which are provided on the circumference with suitable grinding teeth 11. In the example of FIG. 1, the mill rollers 9 and 10 directly produce sponge iron granulate 12 or its pre-product to be ground once again. Compression by roller press 1 must be carried out after the production of assembly 12 described above so that a mass material having a density sufficient for the assembly materials to be dropped into the steel furnace is present. Powdered sponges do not have such properties. Moreover, the sponge iron in powder form is selectively absorbed by the dust removal device so that a significant amount of gas flow as well as an agglomeration phenomenon are often caused.

The embodiments according to FIGS. 8A, 8B and 9A, 9B are now described as embodiments of roller press 1.

8a and 8b show press rollers 2 and 3 provided on their outer surface with a profile (contoured area) in the form of pockets 13 and 13 ', respectively. The pockets 13 and 13 ', respectively, do not exhibit a known size for briquette rollers. Moreover, the distance between the rollers 2 and 3 needs to be increased to produce the desired plate strip 7. The press rollers 2 and 3 described above are designed in substantially the same shape. However, they are joined in a shape in which pockets 13 and 13 'are staggered with respect to each other. Thus, the protruding web shaped portion 14 between the two pockets 13 ′ in roller nip 4 is configured to coincide with the center of the opposing pocket 13. The web portions 15 between the two pockets 13 coincide with the center of the pockets 13 ′ of the press roller 3 in the roller nip 4. Thus, plate strip 7 has a wave like shape when viewed in cross section. The thickness thereof thus becomes the same almost everywhere, and its wavy valleys 16 also serve as a predetermined breakpoint for the subsequent grinding process. Therefore, an impression opposite to the above profile on the roller is produced on the major side 17 of the front side and the major side 18 of the rear side. The fact that the pockets 13 and 13 'are arranged in an offset pattern with respect to each other in the form of a ring-like row encircling on the surfaces of the rollers 2 and 3, respectively, is as uniform as possible despite the provision of such a profile. The result is a strip plate of one thickness.

Another possible design method of the press rollers 2 and 3 described above is made according to the embodiment shown in FIGS. 9A and 9B, wherein profiled web portions 19 and 20 are provided on the outer circumference, respectively. These are elongated in an inclined shape, for example, as shown in FIG. 9B, where these web portions are formed in a counter-inclination form from the center to form a kind of arrowhead shape. The two press rollers 2 and 3 are manufactured substantially identical in turn, but their profiled web shaped portions 19 and 20 are arranged so as to be staggered in an offset shape with respect to each other as the rollers rotate. Profiled mesh shaped portions (webs) 20 are to engage the space between the corresponding profiled webs 19 of the other press roller 2 and vice versa. This also results in the formation of a kind of wavy profile that depends on the shape of the profiled webs 19 and 20. The profiled webs 19 and 20 described above may be provided, for example, by welding. Largely different materials are suitable for the design of the press roller surface. Collars of powder-metallurgical material can also be used. Furthermore, a method can also be used to inter-engage V-shaped webs arranged in opposite directions to create a desired break point (the webs intersect in the roller nip).

In the embodiment according to FIG. 1, a grinder 8 shown in more detail in FIGS. 5A and 5B is used. The mill 8 comprises two milling rollers 9 and 10 operating in opposite directions, each of which is provided with a tooththing 11. The tooth section 11 of the mill roller 9 consists of three tooth rims 21 arranged in parallel. A predetermined interval is given between the rims, respectively. The mill roller 10 operating in coordination therewith comprises four tooth rims 22 designed in a similar manner to the tooth rims 21 described above. The tooth teeth are arranged in a staggered fashion so that they engage one by one in the space between the tooth edges 21 so that the two mill teeth 11 overlap each other. When the strip plate 7 is fed from above, the grinder 8 reliably achieves grinding into an assembled or pre-granulate state. The number of tooth rims or tooth crests described above is determined by the inventors' final analysis depending on the width of strip plate 7 and the size of the desired assembly.

According to FIGS. 6A and 6B, the grinder 8 may be designed like a grinder roller 23 operating against a fixed stop 24. The grinder roller comprises four tooth rims cooperating with the 5-tooth 26 of the fixed restraint device 24 designed as a slide. The mill roller 23 rotates clockwise with respect to the teeth 26 described above. Since the teeth 26 are arranged staggered with respect to the tooth rims 25 they overlap each other and thus allow for proper grinding.

This configuration corresponds, for example, to the embodiment of mill 8 schematically illustrated in FIG. 2.

Other embodiments will now be described with reference to FIGS. 3 and 4, where only the differences will be mainly described as compared to the embodiments described above. Therefore, the same reference numerals are used for the same or similar components in the above-described embodiment, which will be referred to together with the above description.

1 The major difference in the embodiment of FIG. 3 lies in the use of a screw feeder 27. The sponge iron particles 5 are supplied at a high temperature through the filling nozzle 28 of the spiral feeder 27. Since there is some effect of precompression with the screw 29, the spongy iron particles 5 are provided to the roller nip 4 in a very uniform and continuous manner.

 An apparatus similar to FIG. 2 is illustrated in FIG. 4. However, this device also uses gravity feeder 27. The feeder extends over the entire effective feed distance of the press rollers 2 and 3.

Another embodiment of the grinding apparatus is shown in FIG. 7. The device 30 is arranged downstream of the pre-crushing device. For example, the mill according to FIGS. 5 and 6 may be arranged upstream of it. They may be adjusted to pre-mill the intended material to an intermediate assembly size rather than to the final state. The pre-crushed pieces 12 'are fed to the centrifugal roller 31 at a chute 32 comprising a tooth or protruding lining 33. These shredded pieces 12 'are thus hit against one side of the chute 32 designed as impact plate device 34. This results in repeated grinding of the material particles 12 in the final assembled state. The centrifugal roller 32 rotates clockwise, whereby the crushed pieces hit the impact plate 34. In order to prevent abrasion, the shock plates 34 should be provided with a corresponding stable design.

The sequence of various schematic processes for producing an assembly of sponge iron is described below with reference to FIGS. Here, for simplicity of explanation, a schematic illustration of the individual units is made. Therefore, in these units, it may be relied on the design details described in the above-described embodiments and the design configuration according to the prior art.

The sponge iron particles 5 are supplied to the apparatus of the embodiment according to FIG. 10 through the gravity feeder 6. Helical feeders may also be used here. In the roller press 1, the strip plate 7 which is connected to the grinder 8 is extended. In this structure, the grinder 8 has the structure of the grinder which concerns on FIG. However, other pulverizers or shredders of other configurations described above may also be used here.

Pre-granulate particles 12 ′ are provided to the filtration means 35 such that granules of a certain size or less are directly discharged as the final output 12. Pre-assembled material 12 'of a certain size or more is fed to a secondary mill, ie mill 30 according to FIG. The final granulated material released is then provided in final output 12. Repeated control of the final material arriving from the mill 30 is not normally achieved.

In the embodiment according to FIG. 11, the hot sponge particles 5 are again fed through the gravity feeder 6. Other forms of supply are also available. The strip plate 7 is formed in roller press 1 and subsequent milling takes place in the mill 8. The resulting pre-material 12 'is fed to a screen device 35, from which the final product, of a certain size or less, the final product 12 is released. The pre-material 12 'exceeding the above specified size is fed through the grinding device 30 and again in the flow of material particles onto the filtering device 35. Thus iterative control is made through the filtration device 35, where only the sponge iron particles below a certain size are released.

According to the embodiment illustrated in FIG. 12, hot sponge particles are fed through gravity feeder 6. Other modified feeders may be selected here. The hot iron as described above is formed into strip plate 7 in roller press 1 and subsequently crushed in mill 8. As in the other embodiments of FIGS. 10 and 11, the most different grinding apparatus may be used here. The aforementioned pre-material 12 'released from the mill 8 is fed to the filtration device 36. The filtration device 36 comprises a two-stage screen whose final output, spongy iron assembly 12, is released via two stages of screens 37 and 38. Pre-material 12 'having a size larger than the screen particle size of filtration step 37 is fed through mill 30 and provided in the final product 12 in milled form. Pre-material 12 'falling through two screen stages, namely the second screen stage 38, is released as fine amount 39 and mixed again with the spongy iron particles 5 from the top of the gravity feeder 6. The final output 12 is therefore guaranteed to be no larger or smaller than the size range of certain coarse-grained materials.

All of the methods as described above can be combined with one another, for example, in the embodiment shown in FIG. 12, the flow of material released from the mill 30, as in FIG. May be mixed with 'again.

Several variations of the above described methods can be used to produce assembled materials for recycling residues in metallurgical networks (melting furnaces). In contrast, sponge iron through direct reduction of ore can be used as raw material for steel production and put into the furnace for this purpose. The process according to the invention is therefore basically well suited for metallurgical recycling processes and for preparations for the use of raw materials.

1 shows a schematic diagram of a roller press comprising two mill rollers.

2 is a schematic view of a roller press with another embodiment of a crusher;

3 is a schematic view of a roller press with a screw-type feed and a mill of a first variant;

4 is a schematic illustration of a roller press with a spiral feeder and a mill of a second variant;

5A is a schematic front view of the grinder of the first variant;

5B is a top view of the grinder of FIG. 5A.

6A is a schematic front view of the grinder of the second modification.

6B is a top view of the grinder of FIG. 6A.

7 is a schematic front view of a grinder of the third modification.

8A is a schematic view showing a part of the roller press of the first embodiment;

FIG. 8B is a schematic plan view of the press roller of the roller press of FIG. 8A; FIG.

9A is a schematic view of a portion of the roller press of the second embodiment;

FIG. 9B is a schematic plan view of the press roller of the roller press of FIG. 9A; FIG.

10 is a process flow diagram showing the process progress of a first variant of the apparatus for producing granulate material.

FIG. 11 is a process flow diagram showing the process progress of a second variant of the apparatus for producing granulate material. FIG.

12 is a process flow diagram showing the process progress of a third variant of the apparatus for producing granulate material.

Claims (12)

In the apparatus for producing molten iron, A feeder (feeder) for inserting metal-containing material particles such as sponge iron, metal dust, metallurgical residues, and the like; A roller press configured to produce a continuous strip plate by feeding the substance particles under a roller pressing action; A pulverizer for pulverizing the continuous strip plate to produce granulated material (granule); And Apparatus for producing molten iron, characterized in that it comprises a supply means for supplying the granulated material as a raw material for steel production or injecting the granulated material into the melting furnace. The molten iron manufacturing apparatus according to claim 1, wherein the roller press is configured such that longitudinal sections (profiles) are formed on both main sides of the continuous strip plate. 3. The roller press according to claim 2, wherein the roller press is configured to form longitudinal sections (profiles) on both sides of the main side having the same shape and pitch, but offset in the axial direction with respect to each other in the longitudinal direction of the continuous strip plate. Molten iron manufacturing apparatus, characterized in that configured to be made. The molten iron manufacturing apparatus according to any one of claims 1 to 3, wherein the feeder is a screw feeder. 5. Apparatus according to any one of claims 1 to 4, wherein the mill comprises two mill rollers driven in opposite directions with saw blades provided around it. The molten iron according to any one of claims 1 to 4, wherein the grinder comprises a grinder roller and a stationary restraint device 24, wherein the mill roller is configured to act on the stationary restraint device. Manufacturing equipment. The molten iron manufacturing apparatus according to any one of claims 1 to 6, further comprising a pre-milling apparatus. 8. The apparatus for producing molten iron according to claim 7, wherein a centrifugal roller and an impact plate are arranged downstream of the pre-grinding apparatus. 9. The device according to any one of claims 1 to 8, further comprising a screen device having a predetermined screen size and a second grinder, whereby pre-materials of sizes below the designated screen size are directly discharged as final granulated material. On the other hand, the molten iron manufacturing apparatus, characterized in that the pre-material more than the specified screen size is supplied to the second mill. 10. The apparatus of claim 9, wherein the output of the second grinder and the input of the screen device are in a circulating relationship so that all-material having a size exceeding the specified screen size is fed back upstream of the screen device. Molten iron manufacturing apparatus characterized in that the configuration. The device according to any one of claims 1 to 8, further comprising a screen device having a two-stage screen and one second grinder, thereby discharging the final granulated material between the two screen stages. A pre-material of a size less than the specified screen size of the two screens is released and mixed with metal-containing particles upstream of the roller press, and a pre-material having a size larger than the specified screen size is passed through the second mill. Apparatus for producing molten iron, characterized in that to be supplied. The molten iron manufacturing apparatus according to any one of claims 1 to 11, further comprising a converter for supplying the granulated material.