KR20090031402A - Method for hot granulating metal-containing substance particles, such as sponge iron, metallurgical dusts, metallurgical residues, etc - Google Patents

Abstract

A method for hot granulating of substance particles containing metals, such as sponge iron, metallurgical dusts, metallurgical residues, etc is provided to manufacture a granule having a certain size only by applying a recirculation and a filtration system. A method for hot granulating of substance particles containing metals, such as sponge iron, metallurgical dusts, metallurgical residues, etc comprises the following steps of: passing through a material particle(5) at high temperature of 450~900°C range in a roller press(1); producing a strip plate having a consecutive wave typed profile; and a manufacturing a granule having irregular size of the particle by pulverizing the strip plate.

Description

METHOD 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.

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. It is to provide a method for hot-compacting the containing material particles to a high temperature.

In order to achieve the above object, the method according to the present invention comprises the following steps:

Supplying hot material particles to a roller press;

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

Grinding the strip plate into relatively coarse particles (granules).

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 bonding 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 sponge is to be processed on-site, it is granulated (coarse) in correspondence with 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.

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.

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 comprises two oppositely acting press rollers 2 and 3, between which a press nip portion 4 is formed. The press nips 4 described above are formed substantially the same over the entire length. The sponge iron particles 5 are fed to the roller nip 4 via a gravity feeder 6. They are supplied in the on form, in particular the sponges being pressed at elevated temperatures which ensure some ductility and release the binding of the material particles. The strip plate 7 is thus made, which extends substantially over the entire length of the press rollers 2 and 3. Thanks to the ductile properties of the spongy iron particles 5 they are joined 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 supplied sponge particles 5 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 above-mentioned strip plate 7 is supplied to the grinder 8. 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 the sponge iron granulate 12 or its pre-product to be ground once again. Compression by the roller press 1 must be carried out after the production of the 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 an embodiment of the 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 in order 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 coupled 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 the roller nip 4 is configured to coincide with the central portion of the opposing pocket 13. The mesh 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. The plate strip 7 thus has a wave like shape when viewed in cross section. Its thickness thus becomes the same almost everywhere, and its wavy valleys 16 also serve as a predetermined breaking point for the subsequent grinding process. Hence, impressions are created on the front face 17 and back face 18 corresponding to the above profile on the roller. 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, despite the provision of such a profile. The result is a strip plate of as uniform thickness as possible.

Another possible design of the press rollers 2 and 3 described above takes place according to the embodiment shown in FIGS. 9A and 9B, in which 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 in turn made substantially the same, but their profiled web shaped portions 19 and 20 are arranged so that they are offset in an offset shape relative to each other upon rotation of the rollers. Profiled meshed portions (webs) 20 of one press roller 3 are engaged in the space between 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 conforms to 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 that operate in opposite directions, each of which is provided with a tooththing 11. The toothed portion 11 of the mill roller 9 consists of three toothed rims 21 arranged in parallel. A predetermined interval is given between the rims, respectively. The grinder roller 10, which cooperates with it, comprises four tooth rims 22 designed in a manner similar to the tooth rims 21 described above. The saw tooth rims are arranged in a staggered form such that they engage one by one in the space between the tooth rims 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 depends on the width of the strip plate 7 and the size of the desired assembly according to the inventors' final analysis.

According to FIGS. 6A and 6B, the grinder 8 may be designed like a grinder roller 23 operating against a fixed stop 24. The mill 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 proper grinding.

This configuration corresponds, for example, to the embodiment of the 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. With respect to FIG. 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. The sponge iron particles 5 are provided to the roller nip 4 in a very uniform and continuous manner because of the effect of some precompression by the screw 29.

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 a centrifugal roller 31, which includes teeth or protruding linings 33 in a chute 32. These crushed 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 is rotated 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 fed to the apparatus of the embodiment according to FIG. 10 via a gravity feeder 6. Helical feeders may also be used here. In the roller press 1, the strip plate 7 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 so that granulated particles of a certain size or less are discharged directly as the final output 12. Pre-assembled material 12 'of a predetermined size or more is fed to a secondary mill, ie mill 30 according to FIG. The final granulated material released is then provided to the final output 12. Iterative control over the final material from the mill 30 is not usually done.

In the embodiment according to FIG. 11, the hot sponge particles 5 are again fed via a gravity feeder 6. Other forms of supply are also available. A strip plate 7 is formed in the 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 supplied through the grinding device 30 and again in the flow of material particles onto the filtration device 35. Thus, iterative control is made through the filtration device 35, and only sponge particles below a certain size are released.

According to the embodiment illustrated in FIG. 12, hot sponge particles are fed through a gravity feeder 6. Other modified feeders may be selected here. Said hot sponge iron is formed into the strip plate 7 in the roller press 1, and subsequently crushed in the grinder 8. As in the other embodiments of FIGS. 10 and 11, the most different grinding apparatus may be used here. Said pre-material 12 ′ discharged from the mill 8 is fed to the filtration device 36. The filtration device 36 comprises a two-stage screen, the final output of which is the spongy iron assembly 12 is released via two stages of screens 37 and 38. The pre-material 12 ′ of a size larger than the screen particle size of the filtration step 37 is fed through the mill 30 and provided to the final product 12 in milled form. The pre-material 12 ′ falling through the two screen stages, namely the second screen stage 38, is released as a fine amount 39 and the spongy iron particles 5 from the top of the gravity feeder 6. Mixed again). Thus, it is ensured that the final output 12 is not larger or smaller than the size range of a given granulated material.

All methods 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. 12 ') may be mixed again.

Claims (9)

In a method for hot-compacting metal-containing material particles 5 such as sponge iron, metal dust, metallurgical residues, etc. Supplying hot material particles (5) to the roller press (1), wherein the material particles (5) pass through the roller press (1) at a high temperature in the range of 450 ° C to 900 ° C; A process of producing a continuous strip plate 7 by the roller press 1, wherein the front plate 17 and the rear plate 18 of the strip plate 7 correspond to the profile of the roller press 1. A portion 16 is formed, and the valley portion 16 formed on the front surface 17 and the valley portion 16 formed on the rear surface 18 are offset from each other in the longitudinal direction of the strip plate 7. Producing a strip plate (7) having a continuous wave profile with a uniform cross section along the longitudinal direction of the strip plate (7); And Grinding the strip plate (7) to produce granulates of irregular particle size having a density of less than 5 g / cm 3. 2. Process according to claim 1, characterized in that the strip plate (7) is produced with a roller nip in the range of 5 mm to 40 mm. 3. The method of claim 1 or 2, wherein the density of the granulated material is greater than or equal to 3 g / cm 3 and less than 5 g / cm 3. 3. The method according to claim 1, wherein the material particles 5 pass through the roller press 1 at a high temperature in the range of 600 ° C. to 700 ° C. 4. Way. 3. The granulated material 12 according to claim 1 or 2, wherein the strip plate 7 is made of irregular particle size by supplying the crushed pieces to the impact grinder 30 after the strip plate 7 has been ground. A method for high temperature granulation of metal-containing material particles, characterized in that pulverized. 3. Method according to claim 1 or 2, characterized in that the hot material particles (5) are supplied by a spiral feed device (27). 3. The pair of rollers 2, 3 constituting the roller press 1 have the same profile, and the profiled webs 19, 20 are mounted on the rollers 2, 3. Arranged to stagger in an offset shape relative to each other upon rotation of the profiled webs 20 of one roller 3 so as to engage the space between the corresponding profiled webs 19 of the other roller 2. A method for high temperature granulation of metal-containing material particles. A feeder for supplying metal-containing material particles such as sponge iron, metallurgical dust, metallurgical residue, and the like; A roller press (1) comprising a pair of rollers (2, 3) for compressing the metal-containing material particles supplied from the feeder by a roller pressing action to produce a continuous strip plate; A pulverizer for pulverizing the continuous strip plate manufactured by the roller press (1) to produce granulated material; And Supplying the granulated material as a raw material for steel production, or injecting the granulated material into the melting furnace, The pair of rollers 2, 3 each have the same profile with the webs 14, 15, 19, 20 on the outer circumference, the webs 14, 15, 19, 20 having the roller 2 , Spaced between the corresponding profiled webs 14, 19 of the roller 2 so that the profiled webs 15, 20 of one roller 3 are staggered in an offset shape with respect to each other upon rotation of 3). The pair of rollers 2 and 3 are spaced apart so that the size of the nip is 10 mm to 30 mm so that the valley portion 16 is formed corresponding to the webs of the roller and the cross section along the longitudinal direction is thick. Apparatus for hot assembly of metal-containing material particles, characterized in that it produces a strip plate having a uniform continuous wavy profile. 9. The web of claim 8 wherein the webs 14, 15, 19, 20 Apparatus for high temperature granulation of metal-containing material particles, characterized by an arrowhead shape or a V-shape.