TW201540365A - Method and device for preparing and separating a material comprising a composite multi-substance system - Google Patents

Abstract

The invention relates to a method for preparing and separating a material comprising a composite multi-substance system. The material is hereby fed as feed material to a roller mill. An in-bed attrition takes place in the roller mill by means of grinding rollers in a grinding bed, wherein the material is reciprocally attrited through shear stresses and abrasion. The roller mill is operated in such a way that the grinding bed has a minimum height that is greater than the diameter of one of the particles of one of the two compo-nents, and the pressing force of the rollers is selected in order to achieve a contact pressure in the range of from 50 kN/m2 to 140 kN/m2 with respect to the vertically pro-jected area of the average roller diameter. Furthermore the invention relates to a vertical roller mill which is further developed to carry out the method according to the invention.

Description

Method and apparatus for preparing and separating a material comprising a synthetic multi-material system

The present invention relates to a method for preparing and separating a material comprising a synthetic multi-material system, and also to a vertical roll mill for carrying out the method.

About 80 million metric tons of construction waste is produced each year in Germany. Most of this construction waste is crushed concrete. Concrete is basically composed of coarse sand, sand and cement stone, and therefore, the crushed concrete is basically composed of coarse sand, sand and cement stone. Cement stone is especially used to bond two other ingredients.

Especially in areas where natural grit and sand deposits are absent, the milled concrete needs to be prepared such that it can be separated into its individual components. In particular, the focus here is on the recovery of the coarse sand and/or sand used. However, it is essential here that the coarse sand and sand should be purified as completely as possible relative to the cement stone, otherwise the concrete produced in this way may be used when the recovered coarse sand or sand is used for the production of concrete. Has a lower strength.

WO 2011/142663 A1 discloses, for example, a separating apparatus for comminuting milled concrete and, if possible, capable of recovering the individual components of the concrete. However, with the use of such equipment, the desired level of purity of individual recycled components such as grit and grit may not be achieved or may be achieved only under particularly advantageous conditions.

An essential feature of concrete recycling is that, in particular, the coarse sand will not be comminuted during the preparation of the milled concrete, since: otherwise, it can only be used further for the production of inferior quality concrete.

In modern times, a roller mill that is actually a pure pulverizing unit has also been used to prepare and separate materials.

For example, this method is known from WO 2011/107124 A1. In the method described therein, the stainless steel slag composed of the citrate portion and the metal portion is pulverized in a targeted manner, and thereby the portions are separated from each other.

A significant difference in hardness and density difference between the individual portions is utilized during comminution to achieve separation. An essential feature of this method is the continued use of the mill primarily as a comminution unit and the apparent comminution of the supplied feedstock, and also achieves separation only as a secondary downstream property. Through the required pressure-based comminution, this method only allows separation to be achieved with one of the components to be separated, such that it is not comminuted during the grinding process. In other words, separation occurs when one component is ground by roll pressure and the other component is not comminuted. This is possible because of the ductile nature of the ingredients that will not be comminuted. In the case where the pressure during the grinding is slightly too high, the composition is actually deformed, which is not desirable, however, it is not pulverized.

However, this method cannot be used for the preparation and separation of milled concrete because the milled concrete does not have any ductile components and all components or components of the milled concrete will therefore be comminuted by the mill. Therefore, the desired result cannot be achieved, especially the purification and recovery of the coarse sand.

One object of the present invention is to indicate a method and an apparatus in which the method is applied In the case of the apparatus, it is possible to prepare and separate one of the materials comprising the synthetic multi-material system, wherein the composition of the multi-substance system does not have any ductile properties.

This object is a method for preparing and separating a material comprising a synthetic multi-material system and a vertical roller mill having the features of claim 13 according to the invention, according to the invention. The machine is reached.

Advantageous embodiments of the invention are indicated in the scope of the appended claims and in the [embodiments].

According to the method of the invention for preparing and separating a synthetic multi-substance system comprising at least a first component and a second component of the first component, and wherein the two components do not have any ductile properties, The material is fed as a feed material to a roll mill having a grinding disc and a grinding roll for in-bed wear.

A polishing bed of one of the treated material and the material to be treated is formed on the grinding disc during operation, and the grinding rolls are rolled on the grinding bed. During the abrasion in the bed, the material is separated into the components by the shearing stress and abrasion between the particles of the first component and the second component by the grinding roller in the polishing bed, wherein The particles of the first component, the particles of the second component, and particles of the same composition are reciprocally worn.

In order to promote the in-bed wear in the roll mill, the roll mill is operated using one of the rolls with very low punching pressure so that the vertical projected area relative to the average roll diameter reaches only 15 kN/m ² up to a maximum A contact pressure in the range of 140 kN/m ² . Accordingly, the pressing force is selected such that the pressure-based comminution of the first component and/or the second component does not substantially proceed directly via the contact pressure. In other words, the preparation of the material occurs substantially only via the reciprocating wear of the material and the particles of the first component and/or the second component. No pressure based comminution is provided. In the case of a pulverization, this is achieved primarily by the reciprocating abrasion of the material.

Additionally, the roller mill is operated such that the polishing bed has a minimum height greater than the diameter of the particles of one of the two components. After the in-bed wear and treatment in the polishing bed, at least the first component and the second component are removed from the processing circuit of the roller mill and sorted.

A core concept of the method according to the invention can be seen in that a roll mill (especially a vertical roll mill) is no longer used as a comminution unit (where the material to be comminuted is passed through the rolls) Pressure ("stamping"), but the roller mill (especially the grinding bed formed on the roller mill) is used to separate and prepare the feed material into its components, in particular to separate and prepare The first component and the second component. This separation and preparation of the feed material occurs in the polishing bed via reciprocating frictional stress (i.e., abrasion of the material).

Corresponding to the present invention, it is recognized that the formation according to the invention of the polishing bed is carried out via the rollers in the grinding bed using only a very low compressive stress, in the synthesis of the multi-substance system An abrasion process occurs or promotes between the individual components of the composition.

In the case of the in-bed wear according to the invention, it is therefore also possible to separate the multi-material system in the case of a roller mill, the components of which do not have any ductile properties. It is even possible to use a multi-substance system for this separation, the components of such multi-material systems being brittle. In other words, the grinding essentially no longer occurs in the mill, since the pressing force of the rolls is sized such that the comminution is substantially no longer possible via the rolls or their direct influence on the grinding bed. . The separation of the components of the multi-substance system and the associated portion The comminution system is primarily achieved via this abrading process occurring in the polishing bed.

Within the scope of the present invention, abrasion can be understood as the purification of a plurality of components from their own adhesives by reciprocating rubbing against each other. The separation of the components is thereby effected, inter alia, by shear forces on the surface which results in the purification of the individual components which are produced by the rubbing of the components against each other.

An additional core concept that forms the basis of the present invention is to form the polishing bed such that it has a minimum height greater than the diameter of the particles of one of the two components. In particular, a harder or tougher component of the two components of the synthetic multi-body system is selected. This design of the grinding bed ensures that the harder components are not comminuted by the roll pressure. In this connection, it does not necessarily have to be the hardest component of the ingredients. For example, it is also advantageous where the height of the polishing bed is at least as high as the average of one of the components. In this way, there is sufficient chance to ensure that there is no pressure-based comminution during the preparatory process, but there is essentially a preparation and comminution due to the abrading process in the grinding bed, so there is an abrasive-based comminution.

In accordance with the teachings of the present invention, the synthetic multi-substance system can also be composed of more components than the two components indicated herein by way of example. More viscous ingredients are also understood to be harder ingredients in accordance with the meaning of the present invention.

Preferably the roller and the like (which may also be described alternatively as polishing rollers) of a selected punch force chosen such that a contact pressure is generated in the range of m ² of 15kN / m ² to a maximum of 140kN / a. The pressing force depends inter alia on the size of the rolls, the size of the vertical mill, and/or the weight of the rolls. Accordingly, the contact pressure is used as a reference value such that there is a pilot variable regardless of the size of the rolls or the mill. The preferred range of contact pressures is dependent on the awaiting treatment material, wherein the contact pressure is selected such that substantially no pressure based comminution of the abrasive material is present. Because there are many different hardnesses throughout the breadth of the multi-substance system when processing a natural multi-substance system, it is not possible to completely rule out a small portion that is subjected to a poor pressure comminution or unsuccessful treatment.

The invention is further based on the surprising discovery that the processing of the feed material is possible regardless of the fact that the operation of a roll mill is actually much lower than the contact pressure. This is basically the case: in contrast to the mode of operation of the mill to date, the actual grinding no longer occurs, but rather the materials are treated substantially reciprocally with each other and are not processed by the rolls. This situation even leads to the possibility of preparing and separating materials in the case of applying the method according to the invention, the composition of which essentially does not have any density difference.

The punching pressure was advantageously selected so that the shear forces between such particles generated during abrasion in the bed is in the range 5kN / m ² to 70kN / m ² of, in particular between 7kN / m ² and 20kN Between /m ² . The indicated range of shear forces between the particles of the different components of the synthetic multi-material system promotes good wear of one of the polishing beds, such that the synthetic multi-substance system Separation can be carried out in the mill. Here, the shear forces present also allow for a sufficiently large purity of the individual components between themselves without risking too much comminution.

A component necessary in the adjustment of the shear forces is the impulse of the rolls. The pressing force should be desirably set such that the grinding plate is rotated by the rotation of the rolls and the rolls to produce the desired shear force in the grinding bed. In other words, different shearing forces or frictional forces act on the material to be treated. On the one hand, the shearing forces and frictional forces of the individual material particles between themselves, and on the other hand, the shear forces applied to the material via the rollers.

Usually, when a roll mill is used as a pulverizing unit, the rolls are set to Rotating by the grinding bed. In the standard state, it can therefore be assumed that the peripheral speed of the rolls has a magnitude similar to the relative speed of the grinding bed located on the rotating grinding plate. However, if the rolls rotate relatively slowly compared to the grinding plate or the grinding bed, the different speeds at the points of contact result in the creation of shear forces that can be used for in-bed wear in accordance with the present invention.

More specifically, the shear force is compared to the peripheral velocity of the roller by sweeping the particles guided along the underside of the mill or sweeping the particles. The production line is based essentially on the speed of the particles.

In contrast to the standard mode of operation when grinding with a roller mill, it is necessary to significantly increase the height of the grinding bed in the case of applying the method according to the invention. For the method according to the invention, the polishing bed preferably has a maximum height of 8% of the diameter of the abrasive disk, but is preferably about 4% of the diameter of the abrasive disk. In the conventional mode of operation of a roll mill, the abrasive material is actively comminuted or crushed by the rolls. Accordingly, it is desirable to make the grinding gap (i.e., the distance between the grinding rolls and the grinding plate or the grinding disk) not too large, so that the force incorporated into the polishing bed by the grinding rolls can be actively Used to pulverize the abrasive material. If the grinding gap is too large, on the one hand, the abrasive material can be caused to be only partially compressed, and therefore no suitable pressure is applied to the abrasive material, and on the other hand, the abrasive material flows out of the grinding gap so that it is Shifted without being shattered.

In contrast, the movement of the particles or components of the multi-substance system to be abraded in the grinding bed is required in accordance with the mode of operation according to the invention. It is therefore preferred if the height of the polishing bed is significantly higher than the height of the roller mill for exclusive use in the case of grinding. The greater height of the polishing bed results in more relative movement of the particles or components in the polishing bed between themselves, such that the in-bed wear is achieved accordingly.

In principle, the height of the grinding bed can be adjusted by means of the pressing force of the rolls, a feed mass flow rate, a grinding disc speed, a height of one of the grinding discs holding the rim and/or an internal circulation flow.

An increase in the punch pressure of the grinding rolls reduces the height of the grinding bed by an associated increase in one of the contact pressures. An increase in one of the feed mass flows (i.e., if more abrasive material per time unit is fed to the roller mill as a feed material) increases the height of the grinder. In contrast, as the existing abrasive material is removed more quickly from the abrasive disk, a higher abrasive disk speed reduces the height of the polishing bed. The retaining rim of the abrasive disc is located at the edge of the abrasive disc and serves to reduce or prevent the abrasive material from escaping the edge of the disc. If the height of the retaining rim rises, the height of the grinding bed also increases.

One of the parameters that can be used to adjust the height of the grinding bed is the internal circulation flow. Accordingly, particularly in the case of a roller mill having an integrated classifier, the number of such particles removed during the sorting and recycled back to the grinding disc for further processing is a problem. If the internal circulation flow rate increases, the height of the grinding bed also increases. For example, the internal circulation flow can be influenced by means of a classifier setting and also by means of the volume of the process air flow.

For example, it has proven advantageous to increase the material engagement of the multi-substance system to increase the ram pressure in order to achieve the necessary force for wear in the bed, regardless of the increased material engagement. However, because the height of the grinding bed should ideally remain constant, other parameters must be adapted as the height of the grinding bed is initially reduced by increasing the pressure of the press. Accordingly, it is preferred to increase the feed mass flow rate and/or the internal circulation flow rate. Alternatively or additionally, the grinding disc speed can also be reduced. The setting of such parameters is also possible during ongoing operations such that if, for example, the material bonding of the multi-substance system is determined to be greater than The material is joined and it is possible to react to it via the parameters indicated herein.

An additional possibility is to increase the height of the retaining rim. However, this situation is not possible during ongoing operations, or only if there are difficulties. Therefore, if the roller mill used is to be switched to a different multi-substance system or to be designed for this different multi-substance system, this change is mainly used.

If the material of the multi-material system is reduced in engagement, the pressing force is correspondingly reduced, whereby in principle the grinding bed will increase. To counteract this increase, the previously mentioned parameters can now be adjusted in opposite directions.

During the operation of a roll mill, it is in principle necessary to process as high a yield as possible, that is to say as much material as possible per unit of time. If the mass flow is increased in order to increase the yield, it is advantageous in particular in the case of increasing the grinding disc speed in order to maintain the height of the grinding bed. An increase in the pressure of the rolls will actually also reduce the height of the bed, but this situation will result in a change in one of the in-bed wear variables. In particular, the higher pressing pressure of the rolls will increase the grinding pressure (i.e., the force incorporated into the grinding bed by means of the rolls), thereby also increasing the contact pressure. This situation can result in poor preparation and separation of one of the multi-substance systems. It is therefore preferred that if the feed mass flow rate is increased, then this situation should only be compensated by an increase in one of the grinding disc speeds. If the internal recirculation is forcibly increased, the same situation as described above can also be performed. For example, this is a situation where one of the materials is required to have a higher degree of collapse and thus less material is removed via the classifier as a fine. As has been indicated previously, this situation results in more material being fed back to the grinding plate and causing the grinding bed height to increase in a manner similar to the condition in which one of the feed mass flows is increased. It is also preferred here to control this situation substantially only via one of the grinding disc speeds (especially an increase) such that the height of the grinding bed remains constant.

Different roller mill types are known. In some roll mills, the rolls are driven directly. In other roll mills (especially of the LOESCHE type), the rolls themselves are not driven, but are set to rotate via the friction generated between the rolls and the grinding bed. This situation is relatively problem-free in the normal operating mode of a roll mill where the roll mill is used for grinding. However, when a roll mill is used for in-bed wear, it has been determined that the focus on the rotation of the grinding rolls due to the extremely low punch pressure of the grinding rolls is increased.

In this connection, it is preferred to operate the roller mill during startup with a higher pressure than the one selected during the operation. This situation is necessary in order to initially set the rolls with one of the starting torques to be overcome to be rotated. Subsequently, during the in-bed abrading operation, the friction between the grinding bed and the grinding rolls is sufficient to maintain the rotation of the rolls in most cases.

In this connection, if it is determined that the rotation of the rolls is too low, it is preferred to monitor the rotation of the rolls during operation and increase the pressure of the rolls at least over time. Insufficient rotation of one of the rolls causes a change in the shear force introduced into the grinding bed by the rolls, and the quality of the in-bed wear changes accordingly. Through the short-term increase in the pressure of the rolls, it is ensured that the rolls have a sufficient rotation or a sufficient angular momentum. According to the meaning of the invention, one of the rolls being insufficiently rotated is understood to mean that the peripheral speed of the roll is less than 50% of the speed of the material flow below the roll. By approximating, the flow of material below the roller can be assumed to correspond to the rotational speed of the abrasive disk or the abrasive plate below the rollers. Depending on the material, a few percent adjustment can be provided to facilitate a better estimate of this speed.

In order to facilitate the start of the roller mill (especially the setting of the rotation of the grinding rollers), it is advantageous to use the roller bearing in the case of applying only the low allowable pressing force for the wear in the bed. The ground is designed to have a larger play than usual. This situation on the one hand reduces the starting torque and on the other hand also reduces the risk of stopping or the grinding rolls having a rotational speed which is too low.

According to a preferred embodiment, the roller mill operates in an overspeed and/or air flow mode. In this mode of operation as a pure overspeed mill, the prepared abrasive material is conveyed, in particular via the rotation of the grinding disc, over a possible holding rim and falls into an area below the grinding disc. . The abrasive material can be transported away from here. In the air flow mode of operation, the abrasive material falling down the abrasive plate is absorbed by means of a process air stream and is especially blown upwards. Above the grinding disc, in most cases there is a sorter that is delivered to the sorter by means of the process air stream. The classification takes place in the classifier such that the abrasive material that is sufficiently finely prepared is discharged from the preparatory process, and the abrasive material to be further processed is fed back to the preparatory process by so-called removal.

In connection with the present invention, in particular, the in-bed attrition is also described as a grinding process, as this may be considered to be less relevant to a standard grinding process, but different from a different comminution technique. However, the in-bed attrition is carried out by means of a roll mill, and therefore the term for the mill is applied for easier understanding, but no further grinding takes place in the practical sense. In a combined overspeed and airflow mode, not all of the overspeed abrasive material is absorbed by the process air stream that is swept around the abrasive disc, but only a proportion of it is absorbed. An additional ratio falls down and is transported away from the grinding disc by the transfer member.

According to a preferred embodiment, the material comprising the synthetic multi-material system to be prepared and separated is milled concrete. The milled concrete itself consists mainly of coarse sand, sand and cement stone. The method according to the invention allows the grit and the grit to be separated from each other and separated from the cement stone and purified by means of in-bed abrasion. Through the in-bed wear, in particular, The grit and grit are wiped off from the cement stone so that after the process according to the invention, the grit and grit are again substantially present in a pure form and can therefore be reused for concrete production.

In a further advantageous embodiment of one of the methods, a vertical roller mill having a classifier (which may also be integrated) is used. Additionally, a process air stream is set such that a component (e.g., cement stone) and at least a portion of the compound from the first component and the second component (such as cement stone and grit) are by means of the process air stream. The super-speed abrasive material is delivered to the classifier, and the first purified component, such as grit and grit, is removed from the polishing process as a rough material.

Further supposing that at least one proportion of the pulverized second component (such as pulverized cement stone) is removed from the polishing process as a fine material at the classifier, and the second component is less than pulverized particles and the first component Adhesives of a component and the second component, such as cement stone and cement stone and grit compounds, are removed by the classifier and fed back to the abrasive disk. In addition, the grit can be separated from the rough material removed by means of a screen to facilitate further separation in the case of a multi-substance system comprising two or more components.

According to an advantageous embodiment, a vertical roller mill operates in the combined overspeed and air flow modes. The process air stream (which sweeps from below the grinding disc) is set such that it transports only light or small materials in the upward direction of the classifier, especially the smashed cement stone and cement stone and grit adhesives. . Purified heavy components such as grit and grit may be dropped downwardly from the process stream and discharged as a rough material from the polishing process. In addition, the adherends of such components as coarse sand, sand, and cement stone may be discharged as a rough material from the grinding process. The material that is still under-prepared can be detected by means of a picking process and fed back to the in-bed abrading process according to the present invention.

In order to separate the coarse sand and the sand, one of the subsequent separations by means of screening is suitable. The material that achieves the classifier using the process air flow is classified elsewhere. Depending on the setting of the classifier, for example, only the pulverized cement stone is discharged as a fine material, and the remaining material is fed back to the grinding disk. The comminution of the cement stone occurs corresponding to the method according to the invention substantially without a compressive stress but via in-bed abrasion. In other words, the cement stone is ground by other particles and other cement stone. By this grinding, it is also possible to remove the cement stone from the sand and the coarse sand without crushing the sand and the coarse sand itself.

The method according to the invention preferably employs a rotatable grinding disc (one of which is formed on the rotatable grinding disc during operation) and has at least two stationary rotatable grinding rolls (which are in operation) This is carried out by rolling the mill on the abrasive material. In this case, a classifier is preferably disposed above the grinding rolls and additionally provides a means for defining and maintaining a minimum grinding gap between the grinding disc and the grinding rolls.

The vertical roller mill according to the present invention is based on the recognition that one of the abrasive materials on the grinding bed is significantly less compressed than in the case of using one of the conventional grinding beds for coal milling, for example. In-bed wear is necessary or may cause this significantly lower compression in the in-bed wear. However, via this low compression or force effect through the abrasive rolls, there is a problem associated with the localized different hardness and additional properties of the polishing bed which can be of a significantly different level. For example, due to the low compression and relatively large height of the grinding bed, there may be more air inclusions at some points than at other points. If the abrasive rolls are operated with a constant punch pressure, there is a risk that at the point where there are more air inclusions, the grinding rolls compress the polishing bed significantly larger than at other points. It can even cause the grinding rolls to impact as far as the grinding disc. All such variations and phenomena caused by the non-smoothing of the grinding rolls Row. This situation in turn causes vibrations throughout the operation of the vertical mill, which can be undesirable and even partially deleterious. For example, if too much vibration is caused, the preparatory process of applying the vertical roller mill must be stopped.

In this connection, it is recognized in the present invention that it is first necessary in a vertical mill to provide a means for defining and maintaining a minimum grinding gap between the grinding disc and the grinding rolls. This means ensuring that the grinding rolls are prevented from impinging on the grinding disc via the different properties of the grinding bed.

Different possibilities are envisaged in order to implement this component. For example, a corresponding baffle or baffle bumper for the abrasive rolls can be provided in an advantageous embodiment. Another possibility is to design the hydraulic system of the grinding rolls accordingly.

According to a preferred embodiment, a hydraulic system is provided to adjust the ram pressure of the grinding rolls during operation. This hydraulic system of such grinding rolls of gravity offset relative to the vertical projection area of the average diameter of the roll to promote a contact pressure in the range of 15kN / m ² to 140kN / m ² of the. The hydraulic system in a vertical roller mill (especially of the LOESCHE type) is typically designed such that the pressing force of the grinding rollers acts in the same direction as gravity. Generally, by means of the hydraulic system, a contact pressure of 600 kN/m ² up to 1000 kN/m ² or more will be achieved. However, this situation is not desirable in the in-bed wear.

Due to the size of the grinding rolls in different mill systems and their weights of up to 45 tons, it is necessary to provide an inverse hydraulic system to reduce the weight of the grinding rolls stamped on the grinding bed. The hydraulic systems already known (which are used in part to transfer out the grinding rolls) cannot be used here, since they do indeed actually reduce the pressure of the grinding rolls on the grinding bed, but are not suitable for this pressure ( Therefore, the pressing force is maintained at a constant level. In fact, it’s only One of the grinding rolls is counted for rapid removal (for example) for maintenance purposes.

According to an advantageous embodiment, a monitoring system is provided on each of the grinding rolls and the rotation of the grinding rolls is monitored during operation. This situation is necessary when using a vertical roll mill for wear in the bed, because: as already stated, the work takes place with a very low pressure, which means that the grinding rolls are no longer used. Rotate enough. With the aid of the supply monitoring system, this state can be detected and appropriate countermeasures can be initiated, for example by temporarily increasing the impulse.

The invention will be explained in more detail below with reference to the drawings, in which, by way of example, FIG. 1 shows a flow chart for the preparation of concrete according to the invention; FIG. 2 shows a vertical roller mill Cross section; and Figure 3 shows the cutting of the vertical roller mill of Figure 2.

As an example, for the method of the present invention for preparing and separating materials comprising a synthetic multi-material system, Figure 1 shows a flow chart 10 for preparing milled concrete. The methods for the preparation of milled concrete described in more detail below can also be applied to other material systems in the same or similar manner, wherein the individual components do not have ductile properties. The following design should be considered merely as an example to illustrate the exact implementation of the method according to the invention and its advantages as an example. The individual method steps described in relation to this example may also be performed individually, and thus each should be considered separately as part of the present invention.

Typically, concrete particles are produced from milled concrete at a fraction of 0 mm to 63 mm via rupture and separation of the reinforced steel. Subsequently, it usually happens as a part of coarse sand and sand. classification. However, these parts have adhesives that are still not negligible in cement stone. The use of recycled coarse sand and grit as agglomerates up to a maximum of 15% in the production of concrete as a substitute for primary grit and grit is therefore considered to be technically sound.

This threshold value of 15% of the maximum value of the recycled material as a substitute for coarse sand and grit can be significantly shifted upward by means of the method according to the invention.

For this purpose, concrete particles having a particle size of, for example, up to 80 mm are used as starting materials or feed products 11. This concrete granule (which is also described as milled concrete) is fed as a feed material to the roller mill 12 according to the invention. Roll mill 12 is operated in a combined overspeed and air flow mode in accordance with the method of Figure 1, and is also described as a vertical roll mill. The process occurring in the roll mill 12 and the mode of operation of the roll mill 12 will be described in more detail below with reference to FIG.

The roller mill 12 operates as an in-bed wear unit corresponding to the present invention, and does not operate as a pulverizing unit. The pre-compressed and comminuted cement stone 16 can thus be removed from the preparatory circuit at a classifier provided in the roller mill 12, which can in principle also be arranged downstream of the roller mill 12.

By means of overspeed, the rough material 13 is removed from the preliminary preparation in the roll mill 12, the rough material 13 consisting essentially of the prepared coarse sand, sand and still adhering material, but the proportion thereof is significantly smaller than the proportion of the feed material 11 . The material with the adhesive may in particular be coarse sand and/or sand with an adhesive of cement stone. Subsequently, the rough material 13 is subjected to the screen 14, and in the case of the screen 14, the sand particles 17 can be removed as a part of 0 mm to 2 mm. This grit 17 is so well purified via the process 10 according to the invention such that it can be used similarly to the primary grit in concrete production.

The rough material 13 having a size of more than 2 mm is then subjected to density picking Member 15. This situation is used to allow the purified coarse sand 18 having a higher density to be discharged from the processing loop. Further, the material which does not have a sufficiently high density (especially the coarse sand and/or sand, on which the cement stone adhesive still exists) is fed into the bed in the roller mill 12 for wear.

In addition, a method is conceivable, however, the method is not described herein, wherein sand is also fed to the density picking member to separate any adhesive of the cement stone or other impurities that may still be present there and Feed again to the grinder.

Thus, in the case of the method 10 according to the invention, it is possible to extract the coarse sand 18 and the sand particles 17 from the milled concrete (especially the concrete particles 11), the extraction being carried out in high purity so that the components can be similar Used in concrete production in primary coarse sand and sand. A recirculation rate that is much higher than the rate of 15% possible to date is thus achieved.

Density picking can be achieved as dry density picking, for example, by means of wind classifiers, air grips and/or air fluidized bed picking. Alternatively, wet density picking can also be performed. However, the material fed back to the roller mill 12 must then be dried again. Possible examples of wet picking methods are: settling or swimming separation (both statically and dynamically), setting picking, spiral separator or hearth picking, and fluidized bed picking methods.

The roller mill 12 and its operation for in-bed wear will be explained in more detail below with reference to detail 2 .

Figure 2 shows a schematic cross-sectional view of a vertical roller mill 30 of the LOESCHE type. The necessary components of the roller mill 30 are constituted by a frustoconical grinding roller 31 rolled on the polishing bed 41. In the partial cross-sectional view shown here, only two grinding rolls 31 are shown. However, a vertical roller mill 30 having three, four, six or more grinding rolls can also be used.

A polishing bed 41 is formed on the grinding disc 32. Grinding roller 31 itself (it can also be replaced The generation is described as a roller) placed in a fixed position, but rotatable about the axis shown in the drawings. The abrasive disk 32, in turn (as indicated), is rotatable about its central axis. If the grinding disc 32 rotates, the abrasive material 42 present on the polishing bed also rotates. Accordingly, the grinding roller 31 is set to rotate via friction between the abrasive material 42 and the outer contour of the grinding roller 31.

The classifier 34 is disposed above the grinding disk 32 and can be designed both dynamically and statically. The in-bed abrading process in accordance with the present invention is described in more detail below.

The feed or abrasive material 42 (eg, milled concrete) is fed to the preparatory process via the material feedthrough 35. The material feedthrough 35 is thus formed such that the feed material 42 is fed into the central region of the abrasive disk 32.

Via the rotation of the grinding disc 32, on the one hand, the abrasive material is accelerated and on the other hand, the abrasive material is spirally conveyed outwards, so that the grinding roller 31 is rolled over the abrasive material. However, in correspondence with the in-bed wear method according to the present invention, the grinding roller 31 is operated in a manner different from that generally known in the roller mill 30. The grinding rolls are thus essentially not used for pressure comminution of the abrasive material.

Corresponding to the method according to the invention, only very low contact pressure is applied by the grinding roller 31 to the grinding bed 41. This contact pressure is in the range of 15kN / m ² to a maximum of 140kN / m ² of. In particular, it is preferably in a range between 30kN / m ² and 80kN / m ^2. This contact pressure is basically used to incorporate a sufficiently large shear force into the grinding bed 41 such that the particles present there are worn back and forth with each other.

Grinding rolls typically have an average diameter of up to 2.8 m and have a weight of up to 45 t. With this large weight, a contact pressure that is much higher than the maximum possible value in the case of wear in the bed will be achieved. For this reason, an inverse hydraulic system is provided (not shown in Figure 2). Shown) to counteract the gravity of the roller 31. This hydraulic system can apply a negative force to the rocker arm 33 of the grinding roller 31. In other words, the reverse hydraulic system is stamped onto the rocker arm 33 such that the roller 31 rises slightly and a force opposite to its gravity acts on the roller.

Through the further feeding of the new abrasive material 42 and the rotation of the grinding disc 32 (which may also be described as a grinding plate), the partially prepared material on the grinding disc 32 is displaced and overflows to hold the rim 36 to reach The gap between the grinding disc 32 and the mill housing.

The first classification occurs at this time by operation of the mill in both the overspeed and air flow modes. One of the ratios of the overspeed processing material is delivered by process air 37 flowing in from the direction in the direction of the classifier 34, whereby another ratio can be removed from the processing loop as an overspeed rough material.

An essential feature for the first classification is the amount of process air 37 supplied. In addition, the classification can also be affected by the blade ring 38. Accordingly, the process air 37 is adjusted in conjunction with the blade ring 38 such that coarse sand and sand are substantially removed from the processing loop as the overspeed rough material 51. This overspeed rough material is then subjected to screening as described with reference to FIG.

It is also possible to use as the overspeed rough material 51 to remove the adhering material of the coarse sand and/or sand having the cement stone which has not been sufficiently worn out from the treatment circuit. As already stated with respect to Figure 1, the adhesive materials are then fed back to the processing loop along with the new milled concrete.

The first classification is performed via process air and optionally blade rings, which can be considered as density picking.

The blown process air 37 carries, in particular, the pulverized cement stone and also carries sand particles with cemented stone to the classifier 34. The second classification occurs here. This second category is also selected for density.

Here, in the case of using the classifier 34, especially from the processing loop A cement stone that is crushed enough. The pulverized cement stone is removed from the process loop by using the process air at the process air outlet.

The insufficiently comminuted cement stone or the cement material comprising the cement stone and the sand material is fed back to the grinding disc 32 via the coarse sand cone 40 and fed into an additional bed at the other.

In addition, the roller speed sensor 46 is disposed on the roller 31, and the roller speed sensor 46 detects the speed of the roller 31 during operation. This is necessary because the roller can be rotated too slowly via the low pressure, and the roller 31 is stamped onto the grinding bed in the in-bed wear with low punch pressure. If this rotation is detected by means of the roller speed sensor 46, the punching force can be temporarily increased to thereby increase the rotation of the roller.

An essential feature of the method according to the invention and successful in-bed wear is that the grinding bed is designed to be sufficiently high that there are sufficient particles fed into the material to allow for reciprocating wear. The possible influence values for the grinding bed will be explained in more detail below in FIG.

Figure 3 shows the cutting of the roller mill 30 of Figure 2. The same reference numerals as in FIG. 2 are further used herein.

In order to influence the height s of the grinding bed, the feed mass flow rate m _m , _in , the punching force F _{W of the} grinding roller 31 , the grinding disk speed n _S , the height h of the holding rim 36, and the internal circulation flow rate are basically obtained. The internal circulation flow is not shown here in Figure 3. Substantially by the mass feed flow rate considerations _m m, _in the portion of material removed classifier.

The effects of the individual set parameters are explained in more detail below, and in each case it is assumed that the other parameters are kept constant. The aim here is to vary the height s of the grinding bed, in particular below the roller 31, that is to say between the roller 31 and the grinding disc 32. This area is also known as the grinding gap.

In a simple manner, the height s of the grinding bed can be varied via a change in the pressing force F _W of the roller 31 which affects the contact pressure. The contact pressure is the force acting directly on the grinding bed below the roller. If the punching pressure F _{W of the} roller is increased, the abrasive material is largely compressed or pulverized such that the grinding bed height s is reduced. Vice versa, if the roll 31 is punched onto the grinding bed 41 with a lower punching force F _W , the height s of the grinding bed increases.

The increase _in the feed mass flow m _m , _in increases the height s of the grinding bed. If more material per time unit is fed to the grinding disc 32, more abrasive material is located on the grinding disc 32, wherein the residence time of the abrasive material on the grinding disc is assumed to be equal. From this situation it is forcibly seen that the mass flow m _{m,on on the} mill also increases. Since there is therefore more material on the grinding disc 32, the height s of the grinding bed is also higher.

The effect of feeding the mass flow m _m,in can occur in two ways. In one aspect, more feed material can be fed to the roller mill 30 per unit of time. On the other hand, the classifier can be set differently such that there is a higher removal rate at the classifier, which means more material is fed back to the grinding disk 32. The removal rate can also be increased by increasing the process air flow because, in this case, less abrasive material is removed as a rough material from the processing loop, but rather as a potential fine material to the classifier. The feed mass flow m _m,in and the internal circulation flow substantially affect the discharge mass flow m _m,out . If the internal circulation flow increases, refer to the increased cyclic load. In other words, more material is located in the preparatory loop within the mill. In different expression modes, this means that the discharge mass flow m _{m, out} is reduced at least over time. If the feed mass flow m _m,in increases, so that more feed material is fed into the mill, the discharge mass flow m _{m,out is} also forced to increase.

The different possibilities for varying the height of the grinding bed are to increase the disk speed n _S . If the disk speed is increased, the grinding bed height s is reduced. The higher grinding disc speed n _S reduces the residence time of the material to be treated on the grinding disc 32. Therefore, the mass flow rate m _{m,on on the} grinding disc also becomes lower. The height s of the grinding bed is also forced to decrease accordingly.

One additional possibility for influencing the height s of the grinding bed is to hold the rim 36. If the height h is increased, more material accumulates on the polishing plate. This means that, in principle, more material must be present on the grinding disc 32 so that it can discharge the mass flow m _{m, out} and flow from the grinding disc 32.

An essential feature of all the parameters stated herein is that these parameters reciprocally influence each other. The higher holding rim 36 does on the one hand actually result in a higher grinding bed and on the other hand results in a longer residence time of the feed material on the grinding disk 32. Depending on the pressing force F _{W of the} roller 31, this situation results in better wear between the rollers and, in some cases, a poor long stress period and thus in some cases leads to a lower yield in some cases.

As an example, the individual features of the method according to the invention and the vertical roller mill according to the invention are shown here in combination. However, it is apparent that each of these features can also be used individually.

Likewise, especially in Figures 1 and 2, the examples relate to the preparation of milled concrete. However, the method according to the invention can also be used to prepare and separate many different synthetic multi-material systems. For example, in-bed wear in a roll mill (in other words, it promotes only the frictional stress of the material to be treated and does not constitute any actual comminution) can also be used for the preparation of natural slate, which consists of argillaceous rock and impurities (such as , composed of lime, ore or other organic ingredients. It is therefore necessary to ensure the frictional stress of the natural slate in order to produce a ground slate, wherein the individual particles continue to have a plate-like form, regardless of their fineness.

Similarly, the method is suitable for treating clouds consisting of layered citrate and possibly impurities mother. To date, major pure deposits have been utilized. However, this is only the case where a suitable preliminary method for dry abrasion and separation has not been known so far.

The method according to the invention can also be used to prepare kaolin containing industrial grit consisting of kaolin, feldspar and quartz grit. Use and preparation of graphite ore (which consists of graphite and ore substrates) and clay or bentonite (which is contaminated by sand or non-layered tantalate and collapsed by the wear of heavy mineral sand used to separate viscous components) And the density separation of the rutile, zircon, ilmenite or the like from the coated sand fraction below is possible in the case of applying the method according to the invention. It is even possible to prepare FeCr slag which consists of digested slag, corresponding metals and, in some cases, stabilized slag. However, an essential feature here is that the metal component must be a non-ductile component, otherwise the abrasion according to the method of the invention is not possible, otherwise the frictional stress according to the meaning of the invention cannot be achieved.

In the case of the use of the method according to the invention and the roller mill according to the invention, it is therefore possible to prepare and separate the synthetic multi-material system simply and efficiently.

Claims (14)

A method for preparing and separating a material comprising a synthetic multi-material system, wherein the synthesized multi-material system is composed of at least a first component and a second component connected to the first component, and wherein the two Any of the components does not have any ductile properties, wherein the material is fed as a feed material (42) to have a grinding disc (32) and has a grinding roller (31) for in-bed wear. a roll mill (30), wherein a grinding bed (41) comprising a material to be treated and a processed material is formed on the grinding disk (32) during operation, wherein the grinding rolls (31) are during operation The grinding bed (41) is rolled on the surface of the bed by means of the grinding rolls (31) in the grinding bed (41) via the particles of the first component and the second component in their own Separating the material into the components by shear stress and abrasion, wherein the particles of the first component, the particles of the second component, and particles of the same composition are reciprocally worn, wherein the in-bed wear is performed only the use of such grinding rollers (31) one of the punch force (F _W) is operated Roll mill (30), to achieve a contact pressure in the range of 15kN / m ² to 140kN / m ² with respect to the vertical projection area of the average diameter of the roll, which is selected such that the first component and / or the second The pressure-based comminution of the two components is substantially not directly carried out via the contact pressure, wherein the roller mill (30) is operated such that the polishing bed (41) has a greater than one of the two components A minimum height of the diameter of the particles, and wherein at least the first component and the second component are removed from the processing loop of the roller mill (30) and sorted. The method of claim 1, characterized in that the pressing force is selected such that a shear force between the particles generated during wear in the bed is between ⁵ kN/m ² and 70 kN/m ² , in particular It is in the range of 7 kN/m ² to 20 kN/m ² . The method of claim 1 or 2, wherein the height (s) of the polishing bed is controlled to a maximum of 8% of the diameter of the abrasive disk. The method of any one of claims 1 to 3, characterized in that the height (s) of the grinding bed is controlled to be about 4% of the diameter of the grinding disk. The method of any one of claims 1 to 4, characterized in that, by applying a required pressing force (F _W ), by means of a feed mass flow (m _m,in ) The grinding disc height (s) is adjusted by a grinding disc speed (n _S ), a height (h) of one of the grinding discs (31) holding the rim, and/or an internal circulating flow rate. The method of any one of claims 1 to 4, wherein if the material joining of the multi-substance system is increased, the pressing force (F _W ) is increased to achieve in-bed wear, wherein The feed mass flow rate (m _m,in ) increases, the height (h) of the retaining rim increases, the internal circulation flow rate increases and/or the grinding disc speed (n _S ) decreases to maintain a grinding bed height ( s). The method of any one of clauses 1 to 6, wherein the feed mass flow rate (m _m,in ) is increased to increase the yield rate, wherein the grinding disc speed (n _S ) is increased. In order to maintain a grinding bed height (s). The method of any one of claims 1 to 7, characterized in that the grinding rolls (31) having a higher pressing force (F _W ) than that selected during operation are used during startup. The roll mill (30) is operated at a pressure (F _W ). The method of any one of claims 1 to 8, characterized in that the rotation of the grinding rolls (31) is monitored during operation, and if the grinding rolls (31) are determined to be too low Upon rotation, the pressing force (F _W ) of the grinding rolls (31) is increased at least over time. The method of any one of claims 1 to 9, characterized in that the roller mill (30) is operated in an overspeed and/or air flow mode. The method of any one of claims 1 to 10, characterized in that the milled concrete comprising coarse sand, sand and cement stone is fed as a material, and by means of the in-bed wear The coarse sand and the sand are separated from each other and separated from the cement stone. The method of claim 11, wherein the method is characterized in that Using a vertical roller mill having a classifier (34), the process air flow is adjusted such that the cement stone and at least a portion of the cement stone and grit from the overspeed abrasive material are conveyed by means of the process air stream Up to the classifier (34), and the coarse sand and the grit are removed as the rough material from the grinding process, and the crushed cement stone is removed from the grinding process as the fine material at the classifier (34), and the cement stone is removed. And the compound of cement stone and grit is removed by the classifier (34) and fed back to the grinding disc (32), and the grit is separated from the discharged rough material by screening. A vertical roller mill having a rotatable grinding disc (32), a grinding bed (41) of abrasive material (42) formed on the rotatable grinding disc (32) during operation, having at least two stationary rotatable a grinding roller (31) which is rolled on the polishing bed (41) during operation, has a sorter (34) disposed above the grinding rollers (31), and has a means for defining and maintaining the grinding disc (32) a member of a minimum grinding gap between the grinding rolls (31), wherein a hydraulic system for adjusting the pressing force (F _W ) of the grinding rolls (31) during operation is provided, gravity of such grinding roll offset with respect to the vertical projection area of the average diameter of the roll to promote a contact pressure in the range of 15kN / m ² to 140kN / m ² of the. A vertical roller mill according to claim 13 wherein a monitoring system (46) is provided on each of the grinding rollers (31) for monitoring the grinding during operation. The rotation of the grinding roller (31).