MXPA98008729A - Process of trituration in wet, and crusher to implement such proc - Google Patents

Abstract

The invention relates to wet grinding, and to shredders comprising a roller or wheel (4), which rolls on a circular track (18), and is elastically compressed thereon. To make possible the rational use of this type of crusher for wet crushing, the materials to be crushed undergo several crushing operations in layer or bed. During the time in the crusher between two successive grinding operations, water or another liquid (nozzles 12) is added to the materials, which are then drained and / or dried (8 mesh), to reduce their water content to less than 20% by volume

Description

PROCESS OF SHREDDING IN HUMID. AND CRUSHER TO IMPLEMENT SUCH PROCESS FIELD OF THE INVENTION The present invention relates to wet crushing, and to crushers comprising at least one roller that runs on a circular track, and is elastically compressed against the latter.

BACKGROUND OF THE INVENTION The known crushers of the type defined above, a vertical crusher or a ring crusher, where a multigranular layer of materials is compressed for grinding between the roller and the track with sufficient pressure to crush the grains and cause their fragmentation in smaller grains, they are not suitable for wet grinding, since an excessive water content in the crushing materials reduces their efficiency. In wet grinding, the grinding materials generally have a water content of 10 to 60 weight percent, with an average of 30 percent, which is incompatible with a good grinding efficiency.

OBJECT OF THE INVENTION The object of the present invention allows the use rational shredders of this type for wet crushing.

PREFERRED MODALITIES OF THE INVENTION The processes according to the present invention consist of subjecting the materials for grinding, to several operations of crushing, by crushing them in a layer or bed of materials, and during their residence time in the crushing apparatus , and between two successive grinding operations, add water or other liquid to the materials to re-expand the layer of materials, and to make possible the progress of the materials through the grinding apparatus, to control, and possibly to ensure that the gradation of the size of its grain, and then the materials are drained and / or the moisture removed from them, to reduce their water content to less than 20 percent by volume. The draining and moisture removal operations are carried out inside the grinding apparatus, which is configured for this purpose, which makes it possible to achieve a considerable reduction in the well of the plant, avoiding the use of an auxiliary apparatus and transport elements between the different devices. For purposes of implementing the invention, use will be made of a shredder comprising a circular track, fictitiously divided into several track elements, or track circular, separated from each other, where the successive crushing operations, elements to transfer the materials from one track or track element to the next, elements to project water or other liquid on the materials during their transfer from a runway or track element to the next, and suitable elements to ensure the runoff of the materials and / or the removal of moisture from them, before their next step under the roller. In a ring crusher that has a horizontal axis, the tracks will be arranged side by side. The addition of water or other liquid to the materials after each grinding operation makes it possible, on the one hand, to improve the flow of materials and their distribution in a layer of uniform thickness on the track, and on the other hand, remove fine particles immediately after production, which makes subsequent crushing operations more efficient. The water or any other liquid can be projected onto the materials when they are still on the track, for example, by means of nozzles supplied under pressure, which then constitute one of the elements for transferring the materials from a track or track element to the following. In particular, when the crusher is of the rotating ring type, and is driven in rotation at a speed greater than the critical speed, in such a way that the centrifugal force is sufficient to maintain a layer of materials over the entire periphery of the track provided on the ring, it is possible to make use of nozzles placed inside the ring, in its upper portion, and on the side that rises, and whose jets will go towards the track to separate the materials; the action of the jets can be complemented by that of a scraper. The removal of moisture can be effected through the action of the centrifugal force in the portion of the track located upstream of the grinding roller. A pre-compression roller may be provided on the track, immediately in front of the grinding roller, to ensure a complementary moisture removal by pressure. According to a preferred embodiment of the invention, the crusher is of the rotating ring type, and the material feeding device comprises one or more shield or deflection plates configured to intersect the materials separated from the track, provided inside. of the ring, and oriented to deflect it in a direction having a component parallel to the axis of the ring; additional water sprinkler elements can be provided above the diverter plate or plates, to facilitate the flow of the materials. In an alternative way, the plate or plates Deviators can be porous, and water or other liquid can be injected through the plates, to create a liquid film that facilitates the flow of materials. The baffle plate or plates may comprise a top mesh surface, and elements for collecting and discharging water and fine shredded products passing through this surface; then they constitute an element to drain the thick materials. These can be flat or curved, and each plate can be oriented around a horizontal axis, and possibly be tilted around a vertical axis, to be able to adjust the feed speed of the materials to be crushed, and choose the point at which the materials deflected by the plates fall back on the track. The removal of moisture from the materials is done through the action of the centrifugal force, in the area of the track located between the point at which the materials diverted by the plate or diverter plates fall back onto the track and the roller . Preferably, this area will have an angular extension of at least 30 °. In the event that the track is formed inside a drum with a horizontal axis, and supply and discharge areas are configured on either side of the track, runoff elements can be provided in these areas to facilitate the discharge of the water; for the same purpose, when the track is constituted by protection plates that rest on the drum cover, which is generally the case, can be provided with drainage elements under the plates, in the "crushing area." Also a ribbed roller can be used.At its ends, the drum will be provided with ridges annular barrier formers, whose internal diameter will be selected to retain the material inside the supply and discharge areas, respectively, while at the same time, it may be possible for the water to be discharged by overflow. so that it is possible to change its internal diameter "with the object of adjusting its height (radial dimension). The materials retained by these ridges form, at least in the crushing area, a bench that prevents the compressed materials between the roller and the track from being "expelled laterally by the pressure, while at the same time, it is possible to discharge it. the water partially through this bank, if the supply area, or the discharge area, respectively, is provided with runoff elements, and partially by the overflow of the bank.

A rotating mesh, which has a horizontal axis, can be placed at the crusher outlet to select the crushed products. The rejections of the rotating screen can be returned to the track or to the entrance of the crusher, by means of an internal re-cycling device which comprises a conduit arranged inside the crusher, transversely to the track, elements for supplying the rejections of the mesh to the conduit, and possibly elements to facilitate the flow of the rejects through the conduit. The mesh can be integral with the body of the crusher, or it can be supported and driven by individual elements. Water injection elements can be provided in the rotating mesh to facilitate the discharge of the crushed products, and possibly reconstitute with them a pulp of a composition suitable for subsequent processing. According to a first alternative embodiment, the crusher comprises two tracks axially separated from each other inside a drum, with a horizontal axis, two rollers, each suitable for traversing on a track, elements to carry the materials to be crushed towards inside the drum, between the two tracks, and elements to discharge the crushed materials at the two ends of the drum. According to another alternative embodiment, the crusher comprises several tracks separated axially from each other inside a drum with a horizontal axis, several rollers, each suitable for traversing a track, elements for introducing the materials to h into the drum at one end, elements for transferring the materials from one track to the next, and elements for discharging the hed materials at the other end of the drum, draining elements for discharging the water that is provided between the tracks.

BRIEF DESCRIPTION OF THE DRAWINGS The following description makes reference to the accompanying drawings, which show, by way of non-limiting examples, a preferred embodiment of the invention, and two alternative embodiments: In these drawings: Figure 1 is a diagrammatic representation, in cross-section, of a shredder designed in accordance with the invention, Figure 2 is a cross-section along the line AA 'of Figure 1, showing the roll and the internal equipment of the shredder in Figure 3 is a view, analogous to that of the Figure 1, of an alternative embodiment. Figure 4 is a view, analogous to that of Figure 2, of another alternative embodiment.

DETAILED DESCRIPTION OF THE INVENTION The her shown in Figures 1 and 2 is a ring type her constituted by a drum 2 having a horizontal axis supported by one or more pairs of bearings or runners 6 that allow its rotation about its axis . The drum is driven in rotation in the direction of the arrow R by conventional elements, not shown. It is constituted by a cover, whose middle part is internally covered with wear plates, and forms a ring that supports the hing track. A roller 4 is placed inside the cover, to travel on track 18 when the drum is driven in rotation. The roller is integral with an arrow parallel to the axis of the drum, and whose ends, which are located outside the drum, are mounted on bearings able to move in sliding ways, or to be supported by pivoting arms; springs or presses act on the bearings to compress the roller against the track with a previously determined adjustable force. This configuration is conventional, and the arrow and the bearings have been omitted from the drawings, to avoid damaging their readability. The roller can be driven crazy or driven in rotation by a gear motor. In the embodiment shown in Figures 1 and 2, the surface of the track and the peripheral surface The roll is cylindrical, but could be truncated or crindicroconical, or could be formed of several portions having different diameters, as described, for example, in Patent Number 91 09788 in the name of the applicant. The materials for grinding are introduced into the drum by means of a launcher 20 disposed at one end of the drum; at the other end, where the hed materials are discharged, the cover is extended by a cylindrical mesh 14, which is surrounded by a collecting element 15. The nozzles 24, placed inside the mesh 14, make it possible for the hed materials to be sprayed to improve the selection, and possibly produce a pulp of a composition suitable for subsequent processing. A launcher 15, arranged in the drum, transversely to the track, with an appropriate inclination, makes it possible for the rejections of the mesh to be returned to the supply area of the shredder. This launcher is supplied at one of its ends, for example, by means of a device for scraping the inner surface of the mesh; water injection elements can be provided to facilitate the flow of the rejects along the launcher. The her is equipped with a device for feeding materials through passages, constituted by water injection nozzles 12 and an 8 mesh.

The nozzles 12, mounted on a supply tube, not shown, are arranged in such a way that their jets are directed towards the surface of the track, to separate the layer of materials from it. The action of the nozzles could possibly be assisted by a scraper, parallel to the axis of the drum, and arranged near the surface of the track, as described in Patent Number 91 09788, in the name of the applicant; preferably, the edge of the scraper will not be in contact with the surface of the track, but at a short distance from it, to reduce wear. The mesh 8 is constituted by a flat or curved grid and a collection container. It is mounted on a support 26, so as to be able to pivot about a vertical or inclined axis 28, thanks to a system of connecting rod and press, not shown. Possibly it can be mounted to be able to pivot around a horizontal axis, in order that it is possible to change its angle of inclination. A launcher 17 serves to supply the mesh 14 with water and fine crushed materials collected in the collector element of the mesh 8. Elements can be provided to transmit oscillations or vibrations to the mesh 8. As seen in cross section, the interior of the crusher can be divided into five clearly defined areas: a crushing area BC, an elevation area CD, a scraping area DE, a feeding and draining area DF, and a moisture removal area FB. In the longitudinal cross section, the interior of the crusher can be divided into three areas: a supply area 30, a crushing area 31, and a discharge area 32. The inner lining of the supply and / or discharge areas , it can be designed to make it possible for the water to discharge by runoff. In the operation, the materials to be crushed are introduced by means of the launcher 20 to the supply area 30 of the drum, and there form in this area a layer of materials whose progress, parallel to the axis, is controlled by the device of food. A flange 21 of the drum 2, whose internal diameter is substantially equal to that of the layer of materials present on the track, forms a barrier that allows the formation of this layer. The speed of rotation of the drum is greater than the critical speed, in such a way that the layer of materials is retained on the wall of the drum by the centrifugal force, over its entire periphery. Some of the water contained in the materials may be discharged into this area by runoff. To take an elementary volume of the layer of materials present on the track, for example, at the upstream end of the BC crushing area, this first volume undergoes crushing by compression between the roller 4 and the track 18, and then, the rest is compressed against the track by centrifugal force, it is raised towards the scraping area, where it is separated from the track and breaks by the jets of water from the nozzles 12. The grains of material that form this elementary volume, then fall on the mesh 8, where water and grains that are sufficiently fine, pass through the screen surface, are collected by the collecting element, and are transported towards the rotating mesh 14 by means of the launcher 17, while the thicker grains slide along the mesh. The orientation and angle of inclination of the mesh are such that the downward movement of the materials on the mesh is accompanied by a movement that is parallel to the axis of the drum, and whose length is equal to a fraction of the width of the track. By adjusting the orientation of the mesh, it is possible to control the progress of the materials, to force them to go through several grinding cycles, before being discharged from the crusher. The action of the mesh as an element of the step feed device is comparable to that of the diverter plates in the shredder, which is the subject of the aforementioned patent Number 91 09788. The drained materials fall from the mesh on the track, where they reconstitute a layer from which moisture is removed, through the action of the centrifugal force, in the area FB, between the point where they fall and the crushing area BC. To allow satisfactory moisture removal, the angular extent of the FB area must be at least 30 °; the relative positions of roll 4 and screen 8 will be selected to meet this requirement. The centrifugal force also produces, in the area of moisture removal, a gradation of grain sizes of the solid particles, which improves the work of the crusher. When leaving the area of moisture removal, the materials enter the crushing area, to start a new cycle. In this way, the materials pass several times between the roller and the track, before reaching the edge of the track adjacent to the unloading area 32, the number of grinding cycles being equal to the proportion of progress per turn, or step , to the width of the track. It can be considered that each fraction of the track that has a width equal to one step, forms a fictional track element. When the materials reach the unloading area, they are diverted by the mesh 8 towards the rotating mesh 14. The grains of crushed materials, whose dimensions are larger than those of the openings of the mesh 14, are returned to the crusher inlet, Through the internal reclosing device 16. The fine grains and water are discharged at 22. On the outlet side, the drum is provided with a flange 23, whose internal diameter is approximately equal to that of the material layer. This flange allows the formation, in the discharge area 32, of a material bank, which prevents an excessive amount of materials from entering the water, when the fluidity of the layer of the materials present on the track is excessive, and it opposes the expulsion of the materials through the effect of the pressure of the roller in the crushing area. The flanges 21 and 23 can be designed in such a way that their internal diameter can be changed to adapt it to the nature and / or the behavior of the crushed materials; for example, they can be formed of interchangeable segments or rings. As shown in Figure 3, a pre-compression roller 5 can be placed on the track, just before the grinding area, to complement the removal of moisture from the layer of materials, and prevent the water discharged by the removal of moisture on top of the material layer reaches the crushing roller. Known elements will be used to adjust the pressure exerted by the roller 5 on the layer of materials. Measures can be taken to facilitate the download Ie of water in the crushing area: grooving the roller, providing runoff elements under the track protection plates, and so on. Instead of being integral with the drum 2, the mesh 14 could be supported and driven in an independent manner. For example, it could rotate at a speed less than the critical speed, and could be equipped with lifting elements or buckets that make it possible for the recycling launcher 16 to be supplied with the rejects. Instead of comprising a single track fictitiously divided into track elements, the shredder could comprise several tracks axially spaced from one another along the drum, providing elements of runoff and / or moisture removal between the tracks. The shredder shown in Figure 4 comprises two tracks, 18 'and 18", arranged on any side of the median plane of the drum, and axially spaced apart from each other, and two rollers 4' and 4", which run each on a track. The materials to be crushed are carried by a launcher, or any other supply element, not shown, to the space between the two tracks, where they form, through the effect of centrifugal force, a layer that is worn on the two tracks through feeding devices. - Each track is equipped with a step feeding device, for example, of the same type as that of the shredder of Figures 1 and 2, which ensures the movement of the materials from the middle towards each end of the drum. These devices are not shown in Figure 4. The drum cover is extended at each of its ends by a cylindrical mesh 14 ', 14"equipped with 24', 24" water injection nozzles. The collecting elements 15 ', 15"collect the water and the fine grains that have passed through the meshes, and two recycle devices, 16', 16" make it possible for the rejections of the mesh to be sent back to the middle area of the drum. Each half of the crusher of Figure 4 operates as the crusher of Figures 1 and 2. For the same production capacity, this construction makes it possible for the width of the track to be divided in two, which facilitates the discharge of water into the area of moisture removal. Many changes can be made to the described embodiments through the use of equivalent technical elements, and it is clearly understood that those changes fall within the scope of the invention.

Claims (19)

1. NOVELTY OF THE INVENTION Having described the foregoing invention, it is considered as a novelty, and therefore, the content of the following is claimed as property: CLAIMS 1. A process for the wet grinding of minerals or mineral materials, which consists of subjecting the materials to be crushed, to several crushing operations, by grinding in a layer or bed of materials, and during its residence time in the grinding apparatus, and between two successive grinding operations, adding water or other liquid to the materials to destroy the layer of materials and to make possible the progress of the materials to T through the crusher apparatus, to be controlled , and possibly to make it possible to ensure the grading of the size of their grains, and then drain the materials and / or remove the moisture from them, in order to reduce their water content to less than 20 percent.
2. 2. A shredder to implement the process according to claim 1, characterized in that it comprises a circular track (18, 18 ', 18"), which can be divided fictitiously into several elements, or several circular tracks, where the successive crushing operations; one or more rollers (4, 4 ', 4") capable of traversing the track or tracks, and elastically compressed against them; elements (8, 12) for transferring materials from a track or track element to the following: elements (12) for projecting water or other liquid onto the materials during their transfer from one track or track element to the next, and suitable elements to ensure the runoff of the materials and / or the removal of moisture from them, before your next step under a roller.
3. 3. The shredder according to claim 2, characterized in that it comprises nozzles (12) capable of projecting water or other liquid under pressure on the material bed formed on the track or tracks (18), these nozzles also being one of the elements to transfer the materials from one track or track element to the next. .
4. A shredder constituted by at least one rotary ring, having a horizontal axis, at least one roller (4) placed inside the ring, to be able to travel on the track (18) constituted by the inner face of the ring, and elastically compressed against it; elements to carry the materials that are going to be crushed on the track; a device for feeding post-steps materials, including elements to move axially downstream the materials separated from the track, and return them on the latter to undergo another trituration cycle; and elements for unloading the crushed materials, characterized in that the material feeding device comprises elements for separating the materials from the track, these elements being constituted by nozzles (12) placed inside the ring, in its upper portion and on the rising side , and whose jets are directed towards the surface of the track.
5. 5. The shredder according to claim 4, characterized in that the elements for separating the materials from the track, further comprise a scraper arranged transversely to the track, downstream of the nozzles, considering the direction of rotation of the ring.
6. The shredder according to claim 4 or 5, characterized in that the material feeding device comprises at least one baffle plate (8) arranged to intersect the materials separated from the track, and because the plate is permeable.
7. 7. The shredder according to claim 6, characterized in that the deflection plate or plates (8) are constituted by flat or curved meshes, and because elements (17) are provided for collect the water and the fraction of materials that has passed through the mesh, and to download them.
8. 8. The shredder according to claim 6 or 7, characterized in that the deviating plate (8), or each of them, can be oriented by rotating around a substantially vertical axis (28).
9. 9. The shredder according to claim as claimed in claim 6, 7, or 8, characterized in that the shifting plate or each of them, can be tilted by its rotation about a substantially horizontal axis.
10. The shredder according to claim 1 in any of claims 4 to 9, characterized in that it comprises an area (FB) for removing moisture from the materials, between the point where the materials separated by the feeding device fall back on the track and the crushing area (BC), and because the area of moisture removal has an angular extension of at least 30 ° C.
11. The shredder according to claim 1, characterized in that it comprises a pre-compression roller (5) placed on the track (18), immediately in front of the shredder roller (4), to ensure the Removal of moisture from materials by pressure.
12. 12. The shredder according to claim as claimed in any of claims 4 to 11, characterized in that it is constituted by a drum (2) having a horizontal axis, whose interior is divided, from the entrance to the exit, in a supply area ( 30), a grinding area (31) occupied by the track (18), and a discharge area (32), and because the supply area and / or the discharge area is provided with runoff elements.
13. 13. The shredder according to claim 1 in any of claims 4 to 12, characterized in that it comprises a rotating mesh (14) arranged coaxially with the ring, on the exit side of the crushed material.
14. The shredder according to claim 13, characterized in that it comprises an internal recycling device (16) capable of transporting the rejections of the rotating screen (14) to the supply area (30) of the shredder.
15. 15. The shredder according to claim 12, characterized in that the drum (2) is provided with an annular rim (21, 23) at each of its ends.
16. 16. The shredder according to claim 15, characterized in that the flanges (21, 23) are designed in such a way that their internal diameter is You can modify.
17. The shredder according to claim 4, characterized in that it comprises two tracks (18 ', 18") axially spaced apart from one another, inside a drum (2) having a horizontal axis, two rollers (4 ', 4"), each capable of traveling on a track, elements to carry the materials that are to be crushed in the drum, between the two tracks, and two rotating meshes (14', 14") each disposed at one end of the drum
18. 18. The shredder according to claim 1 in any of claims 4 to 16, characterized in that it comprises several tracks axially spaced from each other inside a drum having a horizontal axis, several rollers. , each one capable of traversing a track, elements for introducing materials to be crushed in the drum at one end, elements for transferring materials from one track to the next, and items for unloading the crushed materials at the other end of the drum, and because between the tracks provide elements of runoff to discharge the water.
19. 19. The shredder according to claim as claimed in any of claims 4 to 18, characterized in that the peripheral surface of the roller or rollers is grooved.