RU2648705C2 - Method and device for processing and selecting material from combined multicomponent system - Google Patents

Abstract

FIELD: manufacturing technology.

SUBSTANCE: group of inventions refers to method of processing and separating material from combined multicomponent system and mill for its implementation. Method consists in that material is directed to grinding mill as loadable product. In grinding mill, abrasion is produced in layer by means of grinding rolls, material being rubbed against each other by shearing loads and abrasive wear. While grinding mill is operated in such a way that grinding layer has minimum height, exceeding diameter of one particle of one of the two components, pressing force of rollers being selected so that, to achieve pressure on surface in the range from 50 kN/m² up to 140 kN/m² relative to vertical projection of average diameter of roll surface. Mill is configured to change pressure on surface of layer in above-mentioned range.

EFFECT: method and device allow abrasion of individual components of combined multicomponent system without ductile properties.

14 cl, 3 dwg

Description

The invention relates to a method for processing and separating material from a combined multicomponent system, as well as to a vertical abrasive mill for implementing this method.

In Germany, about 80 million tons of construction waste occur annually. A significant part of them falls on concrete scrap. Concrete and, accordingly, concrete scrap mainly consist of gravel, sand and cement stone. Cement stone is used in particular for bonding two other components.

Just in those places where there are no natural deposits of gravel and sand, it would be desirable to process concrete scrap in such a way that it can be divided into separate components. Of particular interest is the restoration of used gravel and / or sand. However, it is important that the gravel and sand be completely cleaned of cement stone, if possible, because otherwise, using the reclaimed gravel or sand to produce concrete, concrete made in this way will have less strength under certain circumstances.

From WO 201 1/142663 A1, for example, a separating device is known, which makes it possible to grind concrete scrap and, if possible, also restore individual components of concrete. However, with this device, the required degree of purity of the individual processed components, such as gravel and sand, cannot be achieved at all or is achieved only under particularly favorable conditions.

When recycling concrete, it is important that in the process of processing concrete scrap in particular it is not necessary to grind gravel, since otherwise it could be used in the future for the production of concrete only as low-quality.

Recently, abrasive mills, which are, strictly speaking, purely crushing aggregates, have also been used for processing and separating materials.

Such a method is known, for example, from patent WO 2011/107124 A1. In the method described there, stainless steel slag, consisting of a silicate fraction and a metal fraction, is purposefully crushed and at the same time separated from each other. When grinding, a significant difference in the hardness of individual fractions is used, as well as a difference in density in order to achieve separation. It is significant with this method that the mill is further primarily used as a crushing unit and the feedstock is significantly crushed, and only secondarily, as an additional property, is also used to achieve separation. Separation by this method by the necessary pressure-related grinding can only be achieved if one of the components to be separated is ductile, so that it is not crushed during the grinding process. In other words, the separation occurs due to the fact that one of the components is grinded under the influence of inter-roll pressure, while the other component is not crushed. This is possible because the non-ground component has ductile properties. True, at too high pressure during grinding, this component is deformed, which happens unintentionally, but then it is not crushed.

However, a method of this kind is not applicable to the processing and separation of concrete scrap, since there are no ductile materials in the concrete scrap, and accordingly all materials or components of the concrete scrap would be crushed by the mill. Therefore, the necessary result cannot be achieved, in particular the cleaning and restoration of gravel.

The basis of the invention is the task of presenting a method and apparatus that / which would allow for efficient processing and isolation of material from a combined multicomponent system in which the components of the multicomponent system do not have ductile properties.

This problem is solved according to the invention by a method of processing and separating material from a combined multicomponent system with the characteristics of paragraph 1 and a vertical abrasive mill with the characteristics of paragraph 13 of the claims.

Preferred embodiments of the invention are indicated in the dependent claims and in the description.

With the proposed method for processing and separating a combined multicomponent system consisting of at least a first component and a second component associated with the first component, both components not having ductile properties, the material as a feed product enters an abrasive mill, which has a bowl of runners and grinding rollers, for abrasion in the layer.

In the runners' bowl during operation, a crushed layer is formed of processed and processed material, on which grinding rollers roll. When abrasion in the layer by grinding rollers in the crushed layer due to shearing load and abrasion of the particles of the components from each other, the material is divided into the first and second components, and the particles of the first component, the particles of the second component and the particles of the former component are abraded.

To be able to wear a layer of abrasive in the mill it operates with very little pressing force of rolls, so that the surface pressure is achieved only in the range of 15 kN / m to a maximum of 140 kN / m ² with respect to the vertical projection surface mean diameter drum. In this case, the pressing force is selected in such a way that directly by pressure on the surface, the first and / or second component, essentially caused by pressure, is not crushed. In other words, the processing of the material occurs mainly only by mutual abrasion of the material or particles of the first and / or second component. Pressure-related grinding is not provided. If grinding is carried out, this occurs mainly by the mutual friction of materials against each other

In addition, the abrasive mill is operated so that the milled layer has a minimum height exceeding the particle diameter of one of the two components. Following abrasion in the layer or processing in the crushed layer, at least the first and second components are removed from the circular processing process in the abrasive mill and sorted.

The main idea of the proposed method can be considered the use of an abrasive mill, in particular a vertical abrasive mill, no longer as a grinding unit, in which the crushed material is “crushed” by the pressure of the rollers, but the use of an abrasive mill, in particular a grinding layer formed in the abrasive mill, for processing and separating the feed material into its constituent elements, in particular into the first and second components. This processing and separation of the feed material occurs inside the crushed layer by mutual grinding action, i.e. abrasion of the material.

In accordance with the invention, it was found that by the formation of a grinding layer according to the invention with extremely little compression by means of rollers in the grinding layer, the process of abrasion between the individual components of the material consisting of a combined multicomponent system occurs or only becomes possible.

Thus, the use of abrasion in accordance with the invention in a layer allows using an abrasive mill to separate multicomponent systems whose components do not have ductile properties. You can even make this kind of separation of multicomponent systems whose components are fragile. In other words, grinding does not essentially occur in the mill, since the compressive force of the rollers is designed in such a way that grinding by means of the rollers or their effect directly on the crushed layer becomes impossible. Separation and the related partial grinding of the constituent parts of a multicomponent system is achieved mainly through the abrasion process that occurs in the crushed layer.

In the context of the invention, abrasion can be understood as cleaning several components from sticking to each other by mutual friction against each other. In this case, the separation of the components occurs, in particular due to the shearing forces arising during friction against each other on the surfaces, leading to the cleaning of the individual components.

Another main idea underlying the invention is to form a ground layer so that it has a minimum height exceeding the particle diameter of one of the two components. In this case, a more solid or dense of the two components of the combined multicomponent system is selected. By calculating the parameters of the crushed layer, it is achieved that the harder component is not crushed under the influence of inter-roll pressure. In this regard, it is not necessary to talk about the hardest of the components. It is preferable, for example, also when the height of the ground layer is at least equal to the average size of one of the components. Thus, with a sufficient degree of probability, it is ensured that during the processing not grinding caused by pressure occurs, but mainly processing or grinding due to the abrasion processes in the grinding layer, i.e. abrasive grinding.

In accordance with the invention, a combined multicomponent system may also consist of a larger number of components than the two given here as an example. A harder component in accordance with the invention can also be understood as a more firmly bonded component.

Preferably, the selected roller pressing force, which may alternatively be referred to as grinding rollers, is selected so that surface pressure is in the range of 15 kN / m ² to a maximum of 140 kN / m ² . The pressing force in particular depends on the size of the rollers, the size of the vertical mill and / or the weight of the rollers. In this case, the pressure on the surface is used as the initial value, so that the guiding value exists regardless of the size of the rollers or mill. The preferred surface pressure range depends on the materials to be processed, and the surface pressure is selected so that substantially no pressure-related grinding of the milled material occurs. Since there are many different degrees of hardness during the processing of a natural multicomponent system over the entire width of a multicomponent system, the proposed method cannot completely exclude that a small part will be subjected to undesirable crushing or cannot be successfully processed.

In addition, the invention is based on the unexpected conclusion that, despite the fact that, in fact, the pressure on the surface is too small for the abrasion mill to operate, processing of the feed material is still possible. This is mainly due to the fact that, in contrast to the previous mode of operation of the mill, true grinding does not occur anymore, and the materials mainly mutually process each other, and are not processed by rollers. This even leads to the fact that the proposed method also allows you to process and separate materials whose components essentially do not have differences in density.

Preferably, the pressing force is selected so that the shear forces between the particles resulting from abrasion in the layer are from 5 kN / m ² to 70 kN / m ² , in particular from 7 kN / m ² to 20 kN / m ² . These ranges of shear forces between the particles of the various components of the combined multicomponent system provide the possibility of good abrasion in the crushed layer, so that the processing and separation of the combined multicomponent system can be performed in the mill. Moreover, thanks to the shear forces available, it is also possible to achieve a sufficiently high purity of the individual components without risking to produce too strong grinding.

In this case, the component that is essential for setting the shearing forces is the force of the rolling presses. Ideally, it should be adjusted so that, as a result of the rotation of the plate of the runners in combination with the rollers, as well as the rotation of the rollers in the crushed layer, the necessary shearing forces arise. In other words, various cutting and friction forces act on the material being processed: On the one hand, the cutting and friction forces between individual particles of the material; on the other hand, shearing forces that are transmitted through the rollers to the material.

Typically, when using an abrasive mill as a crushing unit, the rollers are driven into rotation by a ground layer. Therefore, in the standard state, it can be assumed that the peripheral speed of the rollers will be similar to the relative speed of the ground layer located on the rotating plate of the runners. However, if the rollers rotate more slowly than the plate of runners or the crushed layer, then as a result of different speeds at the points of contact there are shearing forces that are used for the abrasion in the layer according to the invention.

More precisely, the occurrence of shearing forces mainly depends on the speed of particles conducted longitudinally under the mill, compared with the peripheral speed of the rollers with which they fly past the particles or with which the particles fly past.

In contrast to the standard operating mode during grinding by means of an abrasive mill with the proposed method, it is necessary to significantly increase the height of the ground layer. For the proposed method, the ground layer preferably has a maximum height of 8% of the diameter of the bowl of runners, however, preferably about 4% of the diameter of the bowl of runners. In the normal operating mode of the abrasive mill, the material being crushed is actively crushed or crushed by rollers. In this case, it is desirable that the grinding gap, i.e. the distance between the grinding rollers and the plate of runners or the bowl of runners, is not too large so that the forces transmitted through the grinding rollers to the crushed layer can be actively used for crushing the crushed material. If the grinding gap is too large, it can turn out, on the one hand, that the material to be crushed will only partially compact and, therefore, sufficient pressure will not be exerted on the material to be crushed, and, on the other hand, that the material to be crushed will flow out of the grinding gap so that it will be squeezed out, not crushed.

In contrast, in accordance with the mode of operation according to the invention, it is required that particles or components of the abradable multicomponent system occur in the ground layer. Therefore, it is preferable if the height of the milled layer is significantly greater than in abrasive mills used exclusively for grinding. Due to the greater height of the ground layer, there is more movement of particles or components in the ground layer relative to each other, so that abrasion in the layer is achieved.

In principle, the height of the crushed layer can be adjusted by means of the pressing force of the rollers, the flow of feed material, the speed of rotation of the bowl of runners, the height of the retaining threshold of the bowl of runners and / or the internal recirculation flow.

Moreover, the increase in the pressing force of the grinding rollers due to the associated increase in pressure on the surface reduces the height of the crushed layer. An increase in the flow of feed material, meaning that more grinding material is loaded into the abrasive mill per unit time, increases the height of the grinding layer. In contrast, a higher rotational speed of the bowl of the runners reduces the height of the milled layer, since the existing milled material is faster removed from the bowl of the runners. The support threshold of the runner bowl is located on the edge of the runner bowl and serves to reduce or prevent the spillage of crushed material from the bowl. If the retaining threshold rises, then the height of the ground layer increases.

The next parameter that can be used to control the height of the ground layer is the internal recirculation flow. At the same time, in particular in abrasive mills with an integrated sifter, we are talking about the number of particles that are removed during sifting and again returned to the bowl of the runners for further processing. If the internal recirculation flow is increased, then the height of the ground layer also increases. The internal recirculation flow can be influenced, for example, both by adjusting the sifter and by the volume of the process air stream.

It turned out to be preferable, for example, if the material bonding of the multicomponent system is increased, the pressing force is increased so that, despite the increased material bonding, the necessary forces are obtained for abrasion in the layer. However, since in the ideal case the height of the crushed layer should be maintained at the same level, it is necessary to bring other parameters into account, since as a result of an increase in the pressing force, the height of the crushed layer decreases in the first place. In this case, it is preferable to increase the flow of feed material and / or the internal recirculation flow. Alternatively or additionally, the rotation speed of the bowl of runners can also be reduced. Adjusting these parameters is also possible without stopping the process, so if, for example, during the tests it is established that the material fastening of the multicomponent system has become stronger than before, it will be possible to respond to this by means of the parameters indicated here.

Another possibility is to increase the height of the retaining threshold. However, it is impossible or difficult to do this without stopping the process, so this option is used mainly when the abrasive mill used must be reconfigured to another multicomponent system or calculated in relation to it.

If the material fastening of the multicomponent system is reduced, then the pressing force also decreases, as a result of which, in principle, the height of the crushed layer would increase. To counter this, the above parameters can be aligned in the opposite direction.

When operating an abrasive mill, in principle, it is desirable to provide the highest possible throughput, that is, to process as much feed material as possible per unit time. If the flow of material increases to increase throughput, it is preferable that, in order to maintain the height of the ground layer, in particular, the rotation speed of the bowl of runners is increased. Although an increase in the pressing force of the rollers would also reduce the height of the crushed layer, but this would lead to a change in the variable abrasion in the layer. In particular, as a result of the increase in the pressing force of the rollers, the pressure during grinding would increase, that is, the force transmitted by the rollers to the crushed layer, as a result of which the pressure on the surface also increases. This can lead to poor processing and separation of the multicomponent system. Therefore, it is preferable that if the flow of feed material increases, this is only compensated by an increase in the speed of rotation of the bowl of runners. The same thing can be done if the internal circulation is forcedly increased. This happens, for example, when a higher degree of splitting of the materials is required, and therefore less material is finely disintegrated by the screener. This leads, as shown above, to the fact that more material is returned to the runners plate and, as a result, as with an increase in the flow of the loaded material, the height of the crushed layer increases. It is also preferable here to regulate this mainly only by matching, in particular, increasing, the rotation speed of the bowl of the runners, so that the height of the crushed layer remains unchanged.

Various types of abrasive mills are known. In some, the rollers are driven directly, in others, in particular, of the LOESCHE type, the rollers themselves are not activated, and due to the friction forces arising between the rollers and the crushed layer, they are rotated. In the normal operation of the abrasive mill, in which the abrasive mill is used for grinding, this is relatively uncomplicated. However, when using the abrasive mill for abrasion in the layer, it was found that due to the extremely small pressing forces of the grinding rolls, increased attention should be paid to the rotation of the grinding rolls.

In this regard, it is preferable if the abrasive mill at the time of start-up has a greater compressive force of the rollers than the compressive force selected during operation. This is necessary to first bring the rollers, which have a starting torque requiring overcoming, into rotation. Then, during work on abrasion in the layer, the friction existing between the crushed layer and the grinding rollers is in most cases sufficient to maintain the rotation of the rollers.

In this regard, it is preferable if the rotation of the rollers during operation is monitored, and the pressing force of the rollers is at least periodically increased if rotation of the rollers is too weak. Too little rotation of the rollers causes the shear forces transmitted by the rollers to the crushed layer to change and accordingly the quality of abrasion in the layer also changes. By briefly increasing the pressure force of the rollers, it is achieved that they have sufficient rotation or a sufficient momentum to rotate. In the context of the invention, too low rotation of the rollers is understood if the peripheral speed of the roller is less than 50% of the material flow rate under the roller. It can be approximately assumed that the material flow under the roller corresponds to the rotation speed of the bowl of runners or the plate of runners under the roller. Depending on the material, adjustments of a few percent may be provided to enable a better determination of speed.

To facilitate the actuation of the abrasive mill, in particular the rotation of the grinding rollers, with very little compressive forces admissible for abrasion in the layer, the roller supports are preferably calculated with a larger gap than usual. This, on the one hand, reduces the starting torque, and on the other hand, reduces the risk of stopping or the fact that the grinding rolls will have too low a rotation speed.

In a preferred embodiment, the abrasive mill is operated in a central discharge mode and / or in an air stream mode. In the operating mode as a mill with a purely central discharge, the processed milled material, in particular by rotating the bowl of runners, moves through an existing retaining threshold and falls into the area under the bowl of runners. From here it can be removed. When operating in the air mode, the crushed material falling down over the edge of the runner plate is picked up by the flow of process air and, in particular, is blown up. A sifter is most often located above the bowl of runners, to which the processed crushed material is moved by a stream of technological air. Sifting takes place in the sifter, so that sufficiently finely processed ground material is removed from the processing process, while the ground material to be further processed as the so-called oversize product is returned to the processing process.

In connection with the invention, abrasion in a layer is also called a grinding process in particular, since it can be considered remotely related to standard grinding processes, but differs from them by a different grinding technique. However, abrasion in the milled layer is carried out by means of an abrasive mill, so that to facilitate understanding, terminology for mills is used, although in the strict sense of the word grinding does not occur anymore. In the combined mode of central unloading and air stream, the flow of technological air that passes around the bowl of runners does not pick up all the shredded material overflowing, but only a part of it. Another part falls down and with the help of transporting devices is removed from under the bowl of runners.

In a preferred embodiment of the invention, the material to be processed and released from the combined multicomponent system is concrete scrap. Concrete scrap itself consists mainly of gravel, sand and cement stone. By the proposed method, gravel and sand by abrasion in the layer are separated from each other and from cement stone and cleaned. By abrasion in the layer, in particular, the cement stone is rubbed off from gravel and sand, so that in accordance with the proposed method, gravel and sand are again essentially pure and can again be used for concrete production.

In a further preferred embodiment of the method, a vertical abrasive mill with a screener is used, which can also be integrated. In addition, the process air flow is controlled in such a way that one component, for example, cement stone, and, at least partially, compounds from the first and second components, for example cement stone and sand, are transferred from the overflowing material to the screener, time as the first cleaned component, for example, gravel and sand, as a large product is removed from the grinding process.

It is further provided that at the screener, at least part of the crushed second component, for example, crushed cement stone, and insufficiently crushed particles of the second components, as well as splices from the first and second component, for example, cement, are removed from the grinding process as a fine grinding material stones, as well as compounds of cement stones and sand, are removed from the screener and sent back to the bowl of runners. In addition, sand can be removed from the removed large product by sieving, so as to enable further separation of the multi-component systems from more than two components.

According to a preferred embodiment of the invention, the vertical abrasive mill is operated in a combined central discharge and air jet mode. At the same time, the flow of process air, which flows from below around the bowl of runners, is configured in such a way that it moves upwards only light or small materials, in particular crushed cement stone and adhesions of cement stone and sand, upward in the direction of the screener. The cleaned heavy components, such as sand and gravel, can fall down towards the flow of process air and as a large product are removed from the grinding process. In addition, fused material, also called fusion, from components such as gravel, sand and cement stone, can be removed from the grinding process as a large product. This material that has not yet been sufficiently processed can be detected by sorting processes and, in accordance with the invention, is directed back to the abrasion process in the layer.

Subsequent separation by screening is suitable for separating gravel and sand. Material transferred by the flow of process air to the screener is screened there. As a fine grinding material, depending on the sifter setting, for example, only crushed cement stone is output, while the rest of the material is sent back to the runners bowl. The grinding of cement stone occurs according to the proposed method mainly not by exposure to compression, but by abrasion in the layer. In other words, the cement stone is rubbed by other particles, as well as other cement stones. Such grinding also allows you to remove the cement stone from gravel and sand, without crushing the sand and gravel itself.

The proposed method can be preferably carried out by means of an abrasive mill with a rotating bowl of runners, during operation of which a crushed layer is formed from the crushed material, and with at least two stationary, rotating grinding rollers, which roll over the crushed material during operation. In this case, preferably, a sifter is placed above the grinding rollers and an additional device is provided for determining and maintaining the minimum grinding gap between the bowl of runners and the grinding rollers.

The basis of the vertical abrasive mill according to the invention is the conclusion that during abrasion in the layer, it is necessary or possibly significantly less compression of the crushed product in the crushed layer than in a conventional crushed layer, which, for example, is present when crushing coal. Due to slight compression or force impact through the grinding rollers, there is a problem associated with locally different degrees of hardness and other properties of the crushed layer, which can occur with significant differences. For example, in some places as a result of slight compression and a relatively large height of the crushed layer, there may be more air inclusions than in others. If the grinding rollers work with constant pressing force, there is a danger that in places where there are more air inclusions, the grinding rollers will compress the crushed layer much more strongly than in others. In this case, it may even happen that the grinding rollers break through to the bowl of runners. All of these options and the phenomena that manifest themselves lead to an unstable course of the grinding rollers, which in turn leads to vibrations during operation of the entire vertical mill, which can be undesirable, and partly even harmful. For example, if too strong vibrations occur, it is necessary to stop the processing by means of a vertical abrasive mill.

In view of this, the invention found that for the first time there was a need to provide a device for vertical mills to determine and maintain a minimum grinding gap between the bowl of runners and the grinding rollers. This device allows you to prevent grinding mills as a result of various properties of the crushed layer could break through to the bowl of runners.

There are various ways to implement these devices. For example, in a preferred embodiment, suitable stoppers or buffers may be provided for the grinding rollers. Another possibility is to appropriately calculate the hydraulic system of the grinding rollers.

In a preferred embodiment of the invention, a hydraulic system for adjusting during operation the pressing force of the grinding rollers, which counteracts the force of gravity grinding rollers to allow the pressure to the surface in the range of 15 kN / m ² to 140 kN / m ² with respect to the vertical projection of the average surface drum diameter. Typically, the hydraulic system of vertical abrasive mills, in particular of the LOESCHE type, is calculated so that the pressing force of the grinding rollers acts in the same direction as the force of gravity. Typically, a surface pressure of 600 kN / m ² to 1000 kN / m ² or higher should be achieved through a hydraulic system. However, when abrasion in the layer is undesirable.

Due to the size of the grinding rollers in various grinding systems and their weight up to 45 tons, it is necessary to provide an inverse hydraulic system to reduce the gravity of the grinding rollers, which presses on the crushed layer. Moreover, the well-known hydraulic system, which is used in part for turning the grinding rollers, can no longer be used, since although it reduces the pressure of the grinding rollers on the crushed layer, it is not suitable to maintain this pressure, i.e., the pressing force, at a constant level , and it is designed only for the smooth rotation of the grinding rollers, for example, for maintenance purposes.

In a preferred embodiment of the invention, a monitoring system is provided on each grinding roller that monitors the rotation of the grinding rollers during operation. This is necessary when using a vertical abrasive mill for abrasion in a layer, since, as has already been shown, the work is carried out with very little pressing force, so that it may turn out that the grinding rollers will no longer rotate enough. Thanks to the control systems provided, it is possible to detect this condition and take appropriate countermeasures, for example, to temporarily increase the pressing force.

Below the invention will be described in detail on the basis of schematic embodiments with reference to the figures. The following is shown:

FIG. 1 is a structural diagram of a concrete processing according to the invention;

FIG. 2 is a sectional view of a vertical abrasive mill; and

FIG. 3 a fragment of the vertical abrasive mill of FIG. 2.

In FIG. 1, as an example of the proposed method for processing and recovering material from a combined multicomponent system, a structural diagram 10 for processing concrete scrap is shown. The concrete scrap processing method described below in detail can be applied in the same or similar way to other material systems whose individual components do not have ductile properties. The following implementation should be considered only as a model in order to clearly demonstrate by examples the exact implementation of the proposed method and its advantages. Moreover, the individual methods of the method, which in this example are described as related, can also be performed individually, and, accordingly, they should be considered separately as part of the invention.

Typically, granular concrete with fractions from 0 mm to 63 mm is made from concrete scrap by crushing and separating reinforcing steel. Then, as a rule, gravel and sand fractions are sorted. However, these fractions still have not neglected adhesion of the cement stone. Therefore, the use of regenerated gravel and sand as a filler in the production of concrete instead of primary gravel and sand is considered technically permissible only in an amount up to a maximum of 15%.

By the proposed method, the limit of a maximum of 15% of the regenerated material as a substitute for gravel and sand can be significantly shifted upward.

For this, granular concrete with a grain size, for example, up to 80 mm, is used as a starting material or as a loading product 11. This granular concrete, also called concrete scrap, is fed into an abrasive mill 12 as an infused product. The abrasive mill 12 is operated by the method in FIG. 1 in a combined mode of central discharge and air stream and is also called a vertical abrasive mill. The processes occurring in the abrasive mill 12, as well as the operating mode of the abrasive mill 12 will be discussed in more detail below with reference to FIG. 2.

The abrasive mill 12 is operated in accordance with the invention as a unit abrasive in a layer, and not as a crushing unit. So, in the sifter provided in the abrasive mill 12, which in principle can also be connected to the abrasive mill 12, the treated and crushed cement stone 16 can be removed from the circular processing process.

As a material that does not pass through a sieve, a large product 13, consisting mainly of processed gravel, sand and still fused material, is removed from the treatment in the abrasive mill 12, the proportion of which is still significantly less than in the loaded product 11. The fused material here may represent in particular, gravel and / or sand with cement stone sticking. Then the large product 13 is screened 14, by which sand 17 can be removed as a fraction from 0 mm to 2 mm. This sand 17 is so well cleaned by the proposed method 10 that it can, like the primary sand, be used in the manufacture of concrete.

The large product 13, having a grain size of more than 2 mm, is then sorted by density 15. It serves to remove purified gravel 18 having a higher density from the circular processing process. Material that does not have a sufficiently high density - here we are talking in particular about gravel and / or sand, on which there are still cement stone splices - is again sent to abrasion in a layer in an abrasive mill 12.

Further, a procedure is possible, not shown here, when the sand is also sorted by density, in order, if necessary, to separate cement stone adherence or other impurities that are still present here and again to be sent to the grinding mill for processing.

Thus, the proposed method 10 allows you to extract from concrete scrap, in particular granular concrete 11, gravel 18 and sand 17 so purified that these components can be used in the manufacture of concrete similarly to primary gravel and sand. Due to this, a significantly higher share of return is achieved than the still possible share of 15%.

Sorting according to density can occur as dry sorting by density, for example, using air separators, air-jigging machines and / or by sorting in an air-vortex layer. Alternatively, wet density sorting may also be performed. However, the materials returned to the abrasion mill 12 must be dried again. As methods of wet sorting, for example, separation in heavy liquids is possible, both static and dynamic, jigging sorting, sorting in a screw separator or focus, as well as a method of sorting in a vortex layer.

Next, abrasion mill 12 will be described in more detail, as well as its operation for abrasion in a layer with reference to the detailed FIG. 2.

In FIG. 2 is a schematic sectional view of a vertical LOESCHE type abrasive mill 30. An important component of the abrasive mill 30 is a truncated cone shaped grinding roller 31 rolling over the grinding layer 41. In the partial view shown here, only two grinding rollers 31 are shown in sectional view. However, vertical abrasive mills 30 with three, four, six or more grinding rollers.

The crushed layer 41 is formed in the bowl of the runners 32. The grinding rollers 31 themselves, which alternatively can also be called rolls, are provided as stationary, but rotating around the drawn axis. In turn, the bowl of runners 32, as indicated, can rotate around a central axis. If the bowl of the runners 32 rotates, then the ground product 42 located on the base also rotates. Thus, as a result of friction between the ground product 42 and the outer contour of the grinding rollers 31, the grinding rollers 31 are rotated.

A sifter 34 is provided above the bowl of runners 32, which can be either dynamic or static. Below will be considered in more detail corresponding to the invention, the abrasion process in the layer.

The product being loaded or crushed 42, for example, concrete scrap, is sent through a material loading device 35 to the processing process. In this case, the loading device for the material 35 is arranged in such a way that the loaded product 42 is loaded in the central zone of the bowl of the runners 32.

By rotating the bowl of the runners 32, the crushed product is firstly accelerated, and secondly, spirals outward, so that it is crushed by the grinding rollers 31. However, in accordance with the proposed method of abrasion in the layer, the grinding rollers 31 are operated in a different way than usual It is known in abrasive mills 30. However, they are mainly used not for crushing the crushed product.

In accordance with the proposed method, the grinding rollers 31 exert only very little pressure on the surface of the crushed layer 41. It is in the range from 15 kN / m ² to a maximum of 140 kN / m ² . Preferably, it is in particular in the range of 30 kN / m ² to 80 kN / m ² . This pressure on the surface serves mainly to introduce sufficiently large shearing forces into the milled layer so that the particles therein mutually abrade each other.

Typically, the grinding rollers have an average diameter of up to 2.8 m and a weight of up to 45 tons. With such a large weight, significantly greater surface pressure could be achieved than within which abrasion in the layer would be possible. For this reason, not indicated in FIG. 2 inverse hydraulic system, which serves to counteract the gravity of the rollers 31. This hydraulic system can act as a negative force on the swing arm 33 of the grinding rollers 31. In other words, the inverse hydraulic system presses the swing lever 33 so that the roller 31 is slightly it rises or a force acts on the roller against its gravity.

As a result of further loading of the new crushed material 42, as well as the rotation of the bowl of runners 32, which may also be called the plate of runners, the material in the bowl of runners 32, which has already been partially processed, is forced out and flows through the retaining threshold 36 into the gap between the bowl of runners 32 and the body mills.

Due to the operation of the mill both in the central unloading mode and in the air stream mode, the first screening takes place in this place. A part of the processed material that has not passed through a sieve is moved by the process air 37 coming from below in the direction of the sifter 34, and the other part can be removed from the circular processing process as a large product that did not pass through the sieve.

In this case, the quantity of process air 37 supplied is essential for the first sifting. Additionally, the scapula 38 can also affect sifting. In this case, the process air 37 is regulated in combination with the scapula 38 in such a way that as a large product 51 that has not passed through the sieve, mainly gravel and sand can be removed from the circular processing process. Then, as described in relation to FIG. 1, is screened.

As a large product 51 that has not passed through a sieve from the circular processing process, intergrown materials from gravel and / or sand with cement stone that are still not sufficiently worn can also be removed. Then, the fused materials, as already described with respect to FIG. 1, together with the new concrete scrap, are again sent to the circular processing process.

By means of the process air and the optionally provided blade ring, the first screening is carried out, which can be considered density sorting.

The injected process air 37 carries to the screener 34, in particular, crushed cement stone, as well as sand particles with adhering cement stone. There is a second screening. It also deals with density sorting.

Here, by means of a sifter 34, a sufficiently ground cement stone, in particular, is withdrawn from the circular processing process. This crushed cement stone together with the outgoing process air is removed from the circular processing process through the outlet for the process air.

Insufficiently crushed cement stone or fused material of cement stone and sand is again routed through the cone 40 to the bowl of the runners 32 and thereafter subjected to further abrasion in the layer.

On rolls 31, roll tachometers 46 are additionally provided, which during operation set the speed of rolls 31. This is necessary because, due to the slight pressing force with which rolls 31 press against the crushed layer during abrasion, it may happen that the rolls rotate too slow. If this is recognized by the tachometer of the rollers 46, then the pressing force can be temporarily increased to thereby increase the rotation of the rollers.

Essential for the proposed method and for successful abrasion in the layer is the formation of a sufficiently high ground layer so that there are enough particles of the loaded product to enable mutual abrasion. Possible impacts on the milled layer will be discussed in detail below in FIG. 3.

In FIG. 3 shows a fragment of the attrition mill 30 of FIG. 2. In this case, the same reference signs are still used as in FIG. 2.

In order to influence the height of the ground layer s, mainly the feed stream m _{m, in} , the pressing force F _{W of the} grinding rollers 31, the rotation speed of the runner bowl n _s , the height h of the retaining threshold 36, as well as the internal recirculation flow are available. The internal recycle stream here in FIG. 3 is not indicated. It is essentially a material not passed by the sifter that is part of the feed stream m _{m, in} .

Next, the influence of individual adjustable parameters will be examined in detail, and accordingly it is assumed that other parameters in this regard remain unchanged. Moreover, the goal is to vary the height of the crushed layer s, in particular under the rollers 31, that is, between the rollers 31 and the bowl of runners 32. This zone is also called the grinding slit.

In a simple manner, the height of the ground layer s can be varied by changing the pressing force F _{W of the} rollers 31, which affects the pressure on the surface. The pressure on the surface is the force that acts on the crushed layer directly under the rollers. With an increase in the pressing force F _{W of the} rollers, the product being crushed is more densely compacted or crushed, so that the height of the crushed layer s decreases. Conversely, the height of the crushed layer s increases if the rollers 31 press on the crushed layer 41 with a lower pressing force F _W.

Strengthening the flow of feed material m _{m, in} increases the height of the ground layer s. If more material is loaded into the runner bowl 32 per unit of time, then with the supposedly the same residence time in the runner bowl, there is more material to be crushed. It inevitably follows from this that the material flow in the mill m _{m, on is} also increased. Therefore, when there is more material in the bowl of the runners 32, the height of the ground layer s is higher.

The impact on the flow of the loaded material m _{m, in} can occur in two ways. Firstly, more material per unit time can be loaded into the abrasive mill 30, and secondly, the sifter can be configured differently, so that there will be more sieve in the sifter, i.e. there will be more outflow in the sifter, so that more material will be again sent to the bowl of runners. Oversize product can also be increased by increasing the flow of process air, since in this case less material to be crushed as a large product is removed down from the circular processing process and is instead transported to the screener as a potential fine grinding material. The feed stream m _{m, in} , as well as the internal recycle stream, significantly affect the flow of unloaded material m _{m, out} . If the internal circulation flow increases, then it is said that the circulating mass is increasing. In other words, there is more material inside the mill in a circular process. This means, to put it differently, that thereby the flow of unloaded material m _{m, out} , at least temporarily decreases. If the flow of feed material m _{m, in} increases, that is, more feed material flows into the mill, then inevitably the flow of feed material m _{m, out} also increases

Another possibility to change the height of the ground layer is to increase the speed of rotation of the bowl n _s . If it increases, then the height of the ground layer s decreases. By increasing the speed of rotation of the bowl of runners n _s , the residence time of the processed material in the bowl of runners 32 is reduced. Accordingly, the flow of material in the bowl of runners m _{m, on} is also reduced. As a result of this, the height of the ground layer s inevitably decreases.

Another possibility of influencing the height of the crushed layer s is the retaining threshold 36. If its height h increases, more material accumulates on the plate of runners. This means that, in principle, there should be more material in the bowl of runners 32 so that it can flow _out of the bowl of runners 32 with the flow of unloaded material m _{m, out} .

It is essential for all the parameters presented here that they mutually influence each other. Thus, a higher retaining threshold 36, although it leads, on the one hand, to a higher grinding layer, but, on the other hand, to a longer residence time of the feed material in the bowl of the runners 32. This results, depending on the pressing force F _{W of the} rollers 31 to better abrasion with each other, but under certain conditions also to an undesirable long exposure time and, accordingly, as a result of this under certain conditions to reduce throughput.

As an example, here were shown in combination the individual features of the proposed method, as well as corresponding to the invention of a vertical abrasive mill. But it is obvious that these signs can be respectively applied separately.

Similarly, the example, in particular in figures 1 and 2, was correlated with the processing of concrete scrap. However, the proposed method can be applied to the processing and separation of many different combined multicomponent systems. For example, abrasion in a layer in an abrasive mill, which, in other words, provides the possibility of only an abrasive effect on the material being processed and does not actually perform grinding, can also be used for processing natural slate, consisting of shale and impurities such as lime, ores or other organic components. At the same time, it is essential that an abrasive effect on the natural slate is provided for the production of slate flour, the individual particles of which, despite the fineness of grinding, still have a plate shape.

Similarly, the method is suitable for processing mica, which consists of layered silicates and possible impurities. At the same time, until now, mainly pure deposits have been developed. However, this was only because suitable processing methods for dry abrasion and separation have not yet been known.

The proposed method can also be used in the processing of kaolin-containing industrial sands, consisting of kaolin, feldspar and quartz sand. Also, by the proposed method, it is possible to use and process graphite ore, which consists of graphite and ore matrices, and clay or concrete, contaminated with sand or non-layered silicates, as well as splitting by abrasion of sands of heavy minerals to separate cohesive components and subsequently separating by rutile density, zircon, ilmenite, etc., from the empty sand fraction. FeCr slags can even be processed, consisting of decaying slag, the corresponding metal and, under certain conditions, stabilized slags. However, it is significant that the metal component is not a ductile component, since otherwise abrasion by the proposed method would not have been possible, since the abrasion in accordance with the invention would not have been possible.

The proposed method, as well as the abrasive mill according to the invention, make it possible to process and separate combined multicomponent systems in a simple and effective way.

Claims (14)

1. A method of processing and separating material from a combined multicomponent system, wherein the combined multicomponent system consists of at least a first component and a second component connected to the first component, and both components do not have ductile properties, the material being supplied as a charged product (42) abrasive mill (30) with a bowl of runners (32) and grinding rollers (31) for abrasion in a layer, moreover, in the bowl of runners (32) during operation a crushed layer (41) is formed from the processed and material, moreover, the grinding rollers (31) during operation roll over the crushed layer (41), and when abrading in the layer by grinding rollers (31) in the abrasive layer (41), the material is divided into the first and second particles by shearing load and mutual abrasion components, the particles of the first component, the particles of the second component and the particles of the previous component mutually abrasing each other, and for abrasion in the layer, the abrasive mill (30) is operated only with such a pressing force (F _W ) of the grinding rollers (31), which allows you to achieve surface pressure in the range from 15 kN / m ² to 140 kN / m ² relative to the vertical projection of the surface of the average diameter of the drum, which is selected so that by pressure on the surface essentially did not directly carried out by pressure grinding the first and / or the second component, and the abrasive mill (30) is operated in such a way that the crushed layer (41) has a minimum height exceeding the particle diameter of one of the two components, and moreover, at least e, the first and second components are removed from the circular processing process in the abrasive mill (30) and sorted. 2. The method according to p. 1, characterized in that the pressing force is selected so that the shear forces between the particles arising during abrasion in the layer are in the range from 5 kN / m ² to 70 kN / m ² , in particular from 7 kN / m ² to 20 kN / m ² . 3. The method according to p. 1, characterized in that the height of the ground layer (s) is adjusted to a maximum of 8% of the diameter of the bowl of runners. 4. The method according to p. 1, characterized in that the height of the ground layer (s) is adjusted to about 4% of the diameter of the bowl of runners. 5. The method of claim. 1, characterized in that at the required clamping force (F _W) height of the grinding layer (s) is controlled by the flow of feed material _{(m m, in),} the speed of rotation the grinding table (n _s), the height (h ) the retaining threshold of the bowl runners (31) and / or internal recirculation flow. 6. The method according to p. 1, characterized in that when the material bonding of the multicomponent system is strengthened, the pressing force (F _W ) to achieve abrasion in the layer increases, and to save the height of the crushed layer (s), the flow of the loaded material (m _{m, in} ) increases , the height (h) of the retaining threshold increases, the internal recirculation flow increases, and / or the rotation speed of the bowl of runners (n _s ) decreases. 7. The method according to p. 1, characterized in that to increase the throughput increases the flow of the loaded material (m _{m, in} ), and to maintain the height of the crushed layer (s) increases the speed of rotation of the bowl of runners (n _s ). 8. The method according to claim 1, characterized in that the abrasive mill (30), when driven, is operated with a higher pressing force (F _W ) of the grinding rollers (31) than the pressing force (F _W ) selected during operation. 9. The method according to p. 1, characterized in that the rotation of the grinding rollers (31) is controlled during operation and that the pressing force (F _W ) of the grinding rollers (31) is at least temporarily increased if rotation of the grinding rollers is too weak (31). 10. The method according to p. 1, characterized in that the abrasive mill (30) is operated in the central discharge mode and / or air stream. 11. The method according to p. 1, characterized in that the material is loaded with concrete scrap from gravel, sand and cement stone, and that gravel and sand are separated from each other and from the cement stone by abrasion in the layer. 12. The method according to p. 11, characterized in that a vertical abrasive mill with a sifter is used (34), that the flow of process air is adjusted in such a way that cement stone and at least partially cement compound are not passing through the sieve stone and sand are transported by a process air stream to the sifter (34) and that gravel and sand as a large product are removed from the grinding process, that the sifter (34) has ground cement stone as a thin material ol derived from the grinding process and the cement stone, as well as compounds of the cement paste and sand does not pass through the sifter (34) and are sent back into the bowl of runners (32) and that derived from the major product is separated by sieving the sand. 13. A vertical abrading mill with a rotating bowl of runners (32), in which during operation a crushed layer (41) is formed from the crushed product (42), with at least two stationary, rotating grinding rollers (31), which during operation are rolled over the crushed layer ( 41), with a sifter (34) located above the grinding rollers (31) and with a device for determining and maintaining the minimum grinding gap between the runners bowl (32) and grinding rollers (31), while a hydraulic system is provided for adjusting the pressing force ( F _W ) of the grinding rollers (31) during operation, counteracting the gravity of the grinding rollers to provide pressure on the surface in the range from 15 kN / m ² to 140 kN / m ² relative to the vertical projection of the surface of the average diameter of the roller. 14. A vertical abrasive mill according to claim 13, characterized in that on each grinding roller (31) a monitoring system (46) is provided for monitoring the rotation of the grinding rollers (31) during operation.

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