Bulk material mill for processing coarse material

Abstract

The invention relates to a method for processing a bulk material (8) in a processing plant (1), comprising supplying bulk material (8) into a grinding and separation device (2), wherein the grinding and separation device (2) comprises a grinding device (5) and a separation device (6), the grinding of the bulk material (8) in the grinding device (5) into ground material (23), the separation of the ground material (23) in the separation device (6) into fine material (12) and coarse material (13) and the discharge of the fine material (12) from the grinding and separation device (2), the discharge of at least a part of the coarse material (13) from the grinding and separation device (2), wherein the discharged part of the coarse material (13) amounts to at least 65% by mass of the supplied bulk material (8), and wherein the discharged part of the coarse material (13) is sent for subsequent use. The invention further relates to a processing plant (1) for processing bulk material (8) and the use of a processing plant (1) with a mill and separator for removing dust from ore.

Description

[0001] Bulk material mill for coarse material processing

[0002] The present invention relates to a method for processing a bulk material in a processing plant, a processing plant for processing bulk material and the use of a processing plant with a mill and classifier for dedusting ore.

[0003] Grinding and separating devices are a frequently used means of grinding and processing raw materials. A starting material is fed into the grinding device, where it is comminuted into different fractions, for example, fractions of different grain sizes. The different grain sizes are then separated in a separation device. Sufficiently finely ground fractions are discharged from the grinding and separating device in the form of fines. Coarse fractions with excessively large grain sizes are rejected by the separation device and usually fed back into the grinding device, where they are ground again and thus further comminuted. This cycle is repeated until finally the entire feedstock is discharged from the grinding and separating device in the form of fines.Alternatively, a portion of the coarse material rejected by the separation device can be discharged and thus no longer fed into the grinding device. For example, the discharge of difficult-to-grind materials can increase the productivity of the grinding and separation device. The discharged coarse material is usually disposed of or returned to the grinding device at a later time. The discharged fine material has the desired, sufficiently fine grain size and is fed for subsequent use.

[0004] EP 3 326 720 B1 discloses a process for processing multiphase mineral raw materials. A raw material fed into a mill is crushed by grinding rollers. The ground raw material is then separated into fines and coarse material in a classifier. The fine material is discharged from the plant. A portion of the coarse material rejected by the classifier is discharged from the mill. The remaining coarse material is fed back to the grinding rollers and further crushed until it is finally discharged from the plant in the form of fines.

[0005] The processes known in the prior art have in common that the material to be ground is reduced to a desired grain size, and the reduced material is then discharged from the plant in the form of fines. The removal of undesirable substances or phases that are difficult to grind can be achieved to a certain extent via the coarse material discharge. However, the grain sizes of the coarse material discharged are difficult to control and adjust.

[0006] In this application, grain size refers to the size of individual particles, also called grains. The term "particle" is used in this application as a synonym for "grain." If the particles were perfect spheres, the grain size would represent a measure of the respective sphere diameter. However, since the particles are generally not perfectly spherical but exist in various shapes, the grain size can be interpreted as an equivalent diameter.

[0007] The object of the present invention is to efficiently and precisely separate undesirable substances and grain sizes from ground material and to discharge them from a processing plant. This object is achieved by a method for processing a bulk material according to claim 1, a processing plant for processing bulk material according to claim 12, or a use of a processing plant for dedusting ore according to claim 14.

[0008] A method according to the present invention for processing a bulk material in a processing plant comprises feeding bulk material into a grinding and separating device, grinding the bulk material in a grinding device to produce ground material, separating the ground material into fines and coarse material in a separating device, discharging the fines from the grinding and separating device, and discharging at least a portion of the coarse material from the grinding and separating device. The portion of coarse material discharged from the grinding and separating device amounts to at least 65 percent by mass of the fed bulk material. The portion of coarse material discharged can be supplied for subsequent use. The grinding and separating device comprises the grinding device and the separating device.

[0009] In technical terms, the separation of the ground material can also be referred to as sifting, classifying or sorting.

[0010] The discharged fines can be disposed of, sent to a landfill, or to one or more separate processing stages. For example, the fines can be sent to a separate fines processing plant. Alternatively, or additionally, the fines can be used as filler.

[0011] The bulk material fed in can have at least a first phase and a second phase. The coarse material can have a higher proportion of the first phase than the bulk material fed in. The coarse material can have a higher proportion of the first phase than the fine material. The fine material can have a higher proportion of the second phase than the coarse material. The fine material can have a higher proportion of the second phase than the bulk material fed in.

[0012] The bulk material being fed can be a solid with different phases. The bulk material being fed can be a raw material with multiple mineral phases. The bulk material being fed can be a composite material, such as concrete or a composite plastic. The bulk material being fed can be in one piece or in the form of multiple solids.

[0013] The first phase and the second phase can be bound together in the bulk material. The first phase and the second phase can be loose in the bulk material.

[0014] The first phase and the second phase may contain particles. The particles of the first phase may, on average, have a larger grain size than the particles of the second phase. The particles of the first phase may, on average, have a higher density than the particles of the second phase. The particles of the first phase may, on average, have a larger grain size and a higher density than the particles of the second phase.

[0015] The first phase and the second phase may have different grindabilities. The second phase may have better grindability than the first phase. The second phase may be ground faster and / or into smaller particles, i.e., into particles with a smaller grain size. Due to its grain size, the second phase may be concentrated in the fines by the separation device. Due to its grain size, the first phase may be concentrated in the coarses by the separation device.

[0016] The first phase can contain the same material as the second phase. The first phase can consist of the same material as the second phase. The first phase and the second phase can be largely identical, differing only in grain size.

[0017] The first phase may contain a different material than the second phase.

[0018] The maximum particle size in the fine material can be 0.1 millimeters, preferably 0.05 millimeters, preferably 0.01 millimeters, preferably 0.005 millimeters. The maximum particle size can only represent a theoretical limit. In practice, the separation into fine material and coarse material is additionally influenced by other factors, such as the density and / or shape of the particles, so that particles with a larger grain size than the maximum grain size are sometimes enriched in the fine material. The maximum grain size can therefore represent a grain size limit below which 90 mass percent, in particular 95 mass percent, preferably 99 mass percent of the particles in the fine material fall.

[0019] The second phase may have a grain size that is not preferred for further processing, in particular non-preferred grain sizes. This non-preferred grain size or grain sizes can be discharged from the grinding and separation device as fines.

[0020] In the bulk material being fed in, the first phase can be arranged at least partially, in particular completely, within the second phase. In the bulk material being fed in, the second phase can be arranged partially, in particular completely, within the first phase. In the bulk material being fed in, the first phase can be arranged at least partially connected to the second phase.

[0021] The particles of the bulk material fed into the feed can be composed of the first phase and the second phase. The bulk material fed into the feed can also contain additional phases. During grinding, the first phase and the second phase can be at least partially separated from each other. During grinding, the first phase and the second phase can be at least partially separated from each other and from the other phases. During grinding, the particles of the first phase and / or the particles of the second phase can be crushed.

[0022] The discharged part of the coarse material can be at least 70 mass percent, in particular at least 75 mass percent, in particular at least 85 mass percent, preferably at least 95 mass percent of the bulk material fed in.

[0023] The discharged fine material may amount to a maximum of 35 mass percent, in particular a maximum of 25 mass percent, in particular a maximum of 15 mass percent, preferably a maximum of 10 mass percent, preferably a maximum of 5 mass percent of the bulk material fed in.

[0024] The discharged fine material may amount to at least 1 mass percent, in particular at least 2 mass percent, in particular at least 3 mass percent, in particular at least 5 mass percent, in particular at least 10 mass percent of the bulk material fed in.

[0025] The grinding and separating device may comprise a grinding device and a separating device. The grinding device may be a mill, in particular a vertical mill. The separating device may be a classifier, in particular a rotary classifier. The grinding and separating device may be a mill-classifier combination.

[0026] The separation device can separate the material into fines and coarse materials. The fines can be discharged from the grinding and separation device. The ground material rejected by the separation device, the so-called coarse material, can be discharged separately from the grinding and separation device. Portions of the coarse material rejected by the separation device can also be fed back into the grinding device.

[0027] The sifter, especially the rotary sifter, can have an adjustable speed. The sifter can be driven by a motor. A control unit can control the motor and thus the speed of the sifter, in particular continuously.

[0028] The discharged fines can be controlled via the speed of the classifier. A grain size distribution in the fines can be controlled or at least influenced via the speed of the classifier. A density distribution in the fines can be controlled or at least influenced via the speed of the classifier. The proportion of the fed bulk material discharged as fines can be controlled via the speed of the classifier. A theoretical maximum value for the grain sizes in the fines can be set via the speed of the classifier. A theoretical maximum value for the densities in the fines can be set via the speed of the classifier.

[0029] The discharged coarse material can be controlled via the speed of the classifier. A grain size distribution in the coarse material can be controlled via the speed of the classifier. A density distribution in the coarse material can be controlled via the speed of the classifier. The proportion of the fed bulk material discharged as coarse material can be controlled via the speed of the classifier. A theoretical minimum value for the grain size in the coarse material can be set via the speed of the classifier. A theoretical minimum value for the density in the coarse material can be set via the speed of the classifier.

[0030] A preferred limit value for the grain size in the fines can be set via the speed of the classifier. The person skilled in the art is aware that this grain size limit value does not necessarily represent a 100 percent sharp limit. The discharged fines are generally influenced not only by their grain size, but also, for example, by their density and / or shape. The adjustable preferred limit value for the grain size can therefore be interpreted as a quantile value. A significant proportion, for example at least 90 percent by mass, preferably at least 95 percent by mass, preferably at least 99 percent by mass, of the discharged fines can have grain sizes smaller than or equal to the set preferred limit value.A significant proportion, for example at least 90 mass percent, preferably at least 95 mass percent, preferably at least 99 mass percent of the coarse material rejected by the classifier may have grain sizes larger than the set preferred grain size limit value.

[0031] A preferred limit value for the density of the fines can be set via the speed of the classifier. Those skilled in the art will be aware that this density limit value does not necessarily represent a 100 percent sharp limit, because the discharged fines are influenced not only by their density but also, for example, by their grain size and / or shape. The adjustable preferred limit value for the density can therefore be considered a quantile value. A significant proportion, for example at least 90 percent by mass, preferably at least 95 percent by mass, preferably at least 99 percent by mass, of the discharged fines can have densities less than or equal to the set preferred limit value.A significant proportion, for example at least 90 mass percent, preferably at least 95 mass percent, preferably at least 99 mass percent, of the coarse material rejected by the classifier may have densities greater than the set preferred density limit value.

[0032] The bulk material fed in can consist primarily of ore, in particular metal ore, preferably iron ore. The bulk material fed in can have an ore content of at least 10 mass percent, preferably at least 30 mass percent, preferably at least 50 mass percent. The bulk material fed in can have a metal ore content of at least 10 mass percent, preferably at least 30 mass percent, preferably at least 50 mass percent. The bulk material fed in can have an iron ore content of at least 10 mass percent, preferably at least 30 mass percent, preferably at least 50 mass percent.

[0033] The metal content in the metal ore can be at least 0.1 mass percent, preferably at least 1 mass percent, preferably at least 5 mass percent of the metal ore. The iron content in the iron ore can be at least 1 mass percent, preferably at least 10 mass percent, preferably at least 30 mass percent, preferably at least 50 mass percent of the iron ore.

[0034] The bulk material fed in may consist primarily of concrete, in particular old concrete or recycled concrete. The bulk material fed in may contain at least 10 percent concrete by mass, preferably at least 30 percent concrete by mass, and preferably at least 50 percent concrete by mass.

[0035] The concrete added as bulk material may contain cement paste, hydrated cement, or set cement and aggregate. In the following, the term "cement paste" will be used to refer to cement paste, hydrated cement, and set cement. The cement paste and aggregate can be separated from each other in the grinding device. The cement paste contained in the added concrete may exhibit better grindability than the aggregate contained in the added concrete. The cement paste contained in the added concrete can be largely discharged as fines. The aggregate contained in the added concrete can be largely discharged as coarse material.

[0036] The process can be a process for ore processing, in particular metal ore processing, in particular iron ore processing. Metal ore can be a mixture of rock and metal. The metal can generally be present as a metal compound in the metal ore. According to the present invention, the term "metal compound" also encompasses all sulfidic and oxidic compounds. Iron ore can be a mixture of rock and iron. The iron can generally be present as an iron compound in the iron ore.

[0037] Metal contained in metal ore can be separated from rock contained in the metal ore by the grinding device. The rock may be more grindable than the metal. After the grinding process, the rock may, on average, have a smaller grain size than the metal. After the grinding process, the rock may be at least partially in the form of dust. Due to the smaller grain size, the rock can be specifically enriched in the fines using the separation device and discharged as such. Due to the larger grain size, the metal can be specifically enriched in the coarse material and discharged as such. Through this selective enrichment, metal and rock can be separated efficiently and precisely.

[0038] Iron contained in iron ore can be separated from rock contained in the iron ore by the grinding device. The rock may be more grindable than the iron. After the grinding process, the rock may, on average, have a smaller grain size than the iron. After the grinding process, the rock may be at least partially in the form of dust. Due to the smaller grain size, the rock can be specifically enriched in the fines using the separation device and discharged as such. Due to the larger grain size, the iron can be specifically enriched in the coarse material and discharged as such. Through this selective enrichment, iron and rock can be separated efficiently and precisely.

[0039] The process can be a process for processing old concrete or recycled concrete. In the following, the term "old concrete" will be used to represent old concrete or recycled concrete. The process can be a process for recycling old concrete. The process can be a process for processing and recycling old concrete. The processing and recycling of raw materials, particularly concrete, has become increasingly important in recent years due to ecological and economic aspects. Concrete can contain different aggregates, also known as gravel or sand, which are bound together by cement paste. The aggregates present in the concrete can be separated from the cement paste in the grinding device. The cement paste can be more grindable than the aggregates. The cement paste can be present as cement paste dust after the grinding process.For further use of the aggregate, it can be advantageous if the aggregate is free of cement paste, especially cement paste dust. The cement paste dust can be concentrated in the fines by the separation device and thus separated from the aggregate. The aggregate can be concentrated in the coarse material by the separation device.

[0040] The process can be a process for processing clay in connection with clay calcination. The process can be a process for processing slags, in particular metallurgical slags. The coarse material can be rejected by the separation device toward the grinding device. The coarse material can be directed from the separation device into a grit cone. The rejected coarse material can be conveyed to the grinding device. The grit cone can direct the rejected coarse material to the grinding device. The separation device can be arranged vertically above the grinding device. The rejected coarse material can be conveyed back toward the grinding device by gravity.

[0041] The discharge of at least a portion of the coarse material from the grinding and separation device can take place between the separation device and the grinding device. The discharge of at least a portion of the coarse material from the grinding and separation device can take place via a conveyor screw. For example, the coarse material rejected by the separation device can fall onto the conveyor screw due to gravity. The semolina cone can guide at least a portion of the rejected coarse material onto the separation device, in particular the conveyor screw. The discharge of at least a portion of the coarse material from the grinding and separation device can take place via a chute. The discharge of at least a portion of the coarse material from the grinding and separation device can take place via a chute with subsequent air exclusion. The discharge of at least a portion of the coarse material from the grinding and separation device can take place via an air conveyor trough.The discharge of at least part of the coarse material from the grinding and separation device can take place via an air conveyor trough with subsequent air exclusion.

[0042] All coarse material rejected by the separation device can be discharged from the grinding and separation device.

[0043] The discharged coarse material can be fed to a second separation device. The second separation device can divide the discharged coarse material into at least two fractions, in particular at least three fractions, with different grain sizes. The second separation device can be, for example, a screening device or a second classifier.

[0044] During concrete processing, the cement paste contained in the charged concrete can be largely discharged as fines. The aggregate contained in the charged concrete can be largely discharged as coarse material and fed to the second separation device. The discharged aggregate can be divided into aggregates of different grain sizes in the second separation device. The discharged aggregate can be divided into sand and gravel, for example, in the second separation device. The separation device can be arranged above the grinding device. The discharge of at least some of the coarse material can take place between the separation device and the grinding device.

[0045] A processing plant according to the present invention for processing bulk material comprises a grinding and separating device, a first discharge device, and a second discharge device. The grinding and separating device can comprise a grinding device and a first separation device. The grinding device can be designed to grind bulk material fed into the grinding and separating device into ground material. The first separation device can be designed to separate the ground material into fines and coarse material. The first discharge device can be designed to discharge the fines from the grinding and separating device. The second discharge device can be designed to discharge at least a portion of the coarse material from the grinding and separating device. The processing plant further comprises a second separation device.The second separation device can be designed to separate the discharged coarse material into at least a first fraction and a second fraction. Particles in the first fraction can have, on average, a smaller grain size than particles in the second fraction. The second separation device can be designed to separate the discharged coarse material into at least a first fraction, a second fraction, and a third fraction. The second separation device can be designed to separate the discharged coarse material into at least a first fraction, a second fraction, a third fraction, and a fourth fraction. The fractions can have different average grain sizes.

[0046] The processing plant can alternatively be designed without a second separation device. The processing plant can have a control system designed to control the processing plant such that the portion of the coarse material discharged via the second discharge device amounts to at least 65 percent by mass of the bulk material fed in. The control system can be purely control-oriented or perform closed-loop control based on a measured value. The measured value can be indicative of the relative or absolute quantity of the discharged portion of the coarse material. The measured value can, for example, represent the mass flow of the discharged portion of the coarse material.

[0047] The grinding and separating device can be a mill-classifier combination. The grinding device can be a mill, in particular a vertical mill. The mill can comprise several grinding rollers. The mill can comprise a grinding table.

[0048] The second separation device can be arranged directly downstream of the second discharge device. The first discharge device can be arranged higher than the first separation device. The first discharge device can be arranged vertically above the first separation device.

[0049] The ground material can be transported from the grinding device to the first separation device by means of a process gas stream, in particular heated air. The first discharge device can be an air duct. The fine material can be transported from the first discharge device, in particular by means of a process gas stream, to a filter or a cyclone. In the filter or cyclone, the fine material can be filtered out of the process gas stream and collected. The process gas stream can then be fed back to the grinding and separation device.

[0050] The second discharge device may be a screw conveyor. The second

[0051] The discharge device can be a chute with air seal. The second

[0052] The discharge device can be an air chute with air seal. The second

[0053] Discharge device can be arranged between the first separation device and the

[0054] The second discharge device can be arranged vertically between the first separation device and the grinding device.

[0055] The second discharge device can be designed to discharge at least 65 mass percent, in particular at least 75 mass percent, in particular at least 85 mass percent, preferably at least 95 mass percent of the fed-in bulk material as coarse material.

[0056] The first discharge device can be designed to discharge a maximum of 35 mass percent, in particular a maximum of 25 mass percent, in particular a maximum of 15 mass percent, preferably a maximum of 5 mass percent of the fed-in bulk material as fine material.

[0057] The first separation device can be a sifter, in particular a rotary sifter. The speed of the sifter can be adjustable, in particular continuously adjustable.

[0058] The processing plant may further comprise a motor. The separation device, in particular the classifier, may be driven by the motor.

[0059] The grinding and separating device can comprise a control unit. The control unit can be configured to control the proportion of fines discharged via the first discharge device. The proportion of fines can be specified in relation to the bulk material fed in. The control unit can be electronically connected to the motor. The control unit can be configured to regulate the speed of the motor and thus the speed of the classifier. The control unit can be configured to continuously regulate the speed of the motor and thus the speed of the classifier. The proportion of fines discharged can be regulated via the speed of the classifier. A theoretical maximum grain size in the fines can be regulated via the speed of the classifier.

[0060] The second separation device can be a classifier. The second separation device can be a sieve device. The second separation device can be designed to separate the discharged coarse material into a first fraction and a second fraction. The second separation device can be designed to separate the discharged coarse material into a first fraction, a second fraction, and a third fraction. The second separation device can be designed to separate the discharged coarse material into a first fraction, a second fraction, a third fraction, and a fourth fraction. The fractions can have different average grain sizes than one another. The fractions can have different average densities than one another. The fractions can have different average grain sizes and densities than one another.

[0061] A further aspect of the invention includes the use of a processing plant with a mill and classifier for dedusting ore. The ore is discharged from the processing plant predominantly as coarse material.

[0062] The classifier can be arranged above the mill. "Above" means, in particular, that the classifier is arranged vertically higher than the mill relative to the subsoil, in particular the earth's surface. The classifier can be arranged centrally above the mill in the vertical direction. The classifier can be arranged offset above the mill transversely to the vertical direction. The classifier is arranged, in particular, above a grinding table of the mill. The classifier is arranged, in particular, above the mill's grinding rollers.

[0063] The classifier is, in particular, a rotary classifier. The classifier comprises elements rotating around an axis, in particular a vertical axis.

[0064] Dedusting can be defined as the removal of small particles, especially undesirable small ones. Finely ground dust can cause problems during further processing of the refined ore. Particles with a grain size of less than 0.02 millimeters, especially less than 0.01 millimeters, can be referred to as dust.

[0065] Dust removal can be achieved by discharging fines. The particle size in the fines can be controlled by the speed of the classifier. A maximum value for the particle size in the fines can be controlled by the speed of the classifier. Ore contains, in particular, metal compounds and rocks. The ore, in particular the metal compounds and rocks, can be ground in the mill. The ground metal compounds can be concentrated primarily in the coarse material. The ground rocks can be concentrated primarily in the fines. The ore can be metal ore, in particular iron ore. The ore is ground and crushed in the mill. Metal compounds contained in the ore, in particular iron compounds, can be dissolved from rocks contained in the ore through grinding.The ground rock and metal compounds, especially iron compounds, can be transported to the classifier, where they can be largely separated from each other. The ground rock can be concentrated primarily in the fines. The ground metal compounds, especially iron compounds, can be concentrated primarily in the coarse material.

[0066] In the following, advantageous embodiments of the invention are explained in more detail with reference to the attached figures.

[0067] Figure 1 shows a schematic representation of a processing plant according to the invention for processing bulk material.

[0068] Figure 2 shows a vertical section through a processing plant according to the invention for processing bulk material.

[0069] Fig. 1 shows a schematic representation of a processing plant 1 according to the invention. The processing plant 1 comprises a grinding and separating device 2, a first discharge device 3 and a second discharge device 4. The grinding and separating device 2 comprises a grinding device 5 and a first separation device 6.

[0070] Bulk material 8 stored in a silo 7 is conveyed via a conveyor belt 9 and a first rotary valve 10 to a material feed opening 11 of the grinding and separating device 2 and fed to the grinding device 5. After the grinding process, the bulk material 8 is transported by a process gas stream to the first separation device 6. The first separation device 6 is designed as a rotary classifier in the embodiment shown in Fig. 1. The first

[0071] Separation device 6 separates the ground bulk material 8 into fine material 12 and coarse material 13.

[0072] The fine material 12 is discharged via the first discharge device 3 by means of a

[0073] Process gas stream is discharged from the grinding and separation device 2 and transported to a filter 14. In the filter 14, the fine material 12 is separated from the process gas stream and collected. The fine material 12 collected in the filter 14 can be discharged from the filter 14 via a second rotary valve 15. Part of the filtered process gas stream is returned to the grinding and separation device 2 via a pipeline 16. The remaining process gas stream is discharged from the treatment plant 1 via an outlet 17.

[0074] The coarse material 13 is discharged from the grinding and separating device 2 via the second discharge device 4. In the embodiment shown in Fig. 1, the second discharge device 4 is designed as a screw conveyor. The discharged coarse material 13 is fed to an intermediate storage device 19 via a third rotary valve 18.

[0075] From the intermediate storage 19, the coarse material 13 can then be discharged from the processing plant 1 or fed to a second separation device 20. The second separation device 20 shown in Fig. 1 is a screening device and separates the coarse material 13 into four fractions B, C, D, and E with different grain sizes. The fine material 12 discharged from the filter 14 can be considered a first fraction A. The second separation device 20 accordingly separates the coarse material 13 into a second fraction B, a third fraction C, a fourth fraction D, and a fifth fraction E.

[0076] Fig. 2 shows a section of a processing plant 1 according to the invention. Essentially, Fig. 2 depicts the grinding and separation device 2 of the processing plant 1. Bulk material 8 is fed into the grinding device 5 via the material feed opening 11. In the embodiment shown in Fig. 2, the grinding device 5 comprises a grinding table 21 and several grinding rollers 22. The grinding rollers 22 comminute the bulk material 8 into ground material 23.

[0077] A process gas stream, for example air or hot gas, is introduced into the grinding and separating device 2 via an air inlet opening 24 in the lower region of the grinding device 5. The process gas stream transports sufficiently finely ground material 23 to the first separation device 6. In the embodiment shown in Fig. 2, the first separation device 6 is a rotary classifier. The first separation device 6 comprises a vane wheel 25 driven by a motor 26. The grinding and separating device 2 further comprises a control unit 27. The control unit 27 is electronically connected to the motor 26 and is designed to control the motor 26 and thus the rotational speed of the vane wheel 25. The rotational speed of the vane wheel 25 can be continuously regulated by the control unit 27 via the motor 26.

[0078] Sufficiently finely ground material 23 is discharged from the first separation device 6 as fine material 12 via the first discharge device 3. The grinding and separating device further comprises a semolina cone 28. Insufficiently finely ground material 23, so-called coarse material 13, is rejected by the separation device 6 toward the semolina cone 28. The semolina cone 28 guides the coarse material 13 to the second discharge device 4. In the embodiment shown in Fig. 2, the second discharge device 4 is designed as a screw conveyor. The coarse material 13 is discharged from the grinding and separating device 2 via the second discharge device 4. The discharged coarse material 13 is then supplied for subsequent use.

Claims

Claims 1. A method for processing a bulk material (8) in a processing plant (1), comprising: - feeding bulk material (8) into a grinding and separating device (2), wherein the grinding and separating device (2) comprises a grinding device (5) and a separating device (6), - grinding the bulk material (8) in the grinding device (5) to ground material (23), - Separating the ground material (23) in the separation device (6) into fine material (12) and coarse material (13), - discharging the fine material (12) from the grinding and separating device (2), and - discharging at least a portion of the coarse material (13) from the grinding and separating device (2), and wherein the discharged portion of the coarse material (13) amounts to at least 65 mass percent of the bulk material (8) fed in.

2. A method for processing a bulk material according to claim 1, wherein the bulk material (8) fed in has at least a first phase and a second phase, wherein the coarse material (13) has a higher proportion of the first phase than the bulk material (8) fed in.

3. A method for processing a bulk material according to claim 2, wherein the first phase and the second phase comprise particles, wherein the particles of the first phase have on average a larger grain size than the particles of the second phase and / or the particles of the first phase have on average a higher density than the particles of the second phase.

4. A method for processing a bulk material according to claim 2 or 3, wherein the first phase comprises a different material than the second phase.

5. A method for processing a bulk material according to one of the preceding claims, wherein a maximum grain size of particles in the fine material (12) is 0.1 millimeters, preferably 0.05 millimeters, preferably 0.01 millimeters, preferably 0.005 millimeters.

6. A method for processing a bulk material according to one of the preceding claims, wherein the discharged part of the coarse material (13) amounts to at least 75 mass percent, in particular at least 85 mass percent, preferably at least 95 mass percent of the fed-in bulk material (8).

7. A method for processing a bulk material according to one of the preceding claims, wherein the separation device (6) is a sifter, in particular a rotary sifter.

8. A method for processing a bulk material according to claim 7, wherein a grain size distribution in the coarse material (13) can be controlled or at least influenced via a speed of the classifier.

9. A method for processing a bulk material according to one of the preceding claims, wherein the bulk material (8) consists primarily of ore, in particular metal ore, preferably iron ore.

10. A method for processing a bulk material according to one of claims 1 to 8, wherein the bulk material (8) consists primarily of concrete, in particular old concrete or recycled concrete.

11. A method for processing a bulk material according to one of the preceding claims, wherein the separation device (6) is a first separation device (6) and the discharged coarse material (13) is fed to a second separation device (20), wherein the second separation device (20) divides the discharged coarse material (13) into at least two fractions, in particular at least three fractions, in particular at least four fractions, with mutually different grain sizes and / or densities.

12. A processing plant (1) for processing bulk material (8), comprising: a grinding and separating device (2) comprising a grinding device (5) and a first separating device (6), wherein the grinding device (5) is designed to grind a bulk material (8) fed into the grinding and separating device (2) into ground material (23), and the first separating device (6) is designed to separate the ground material (23) into fine material (12) and coarse material (13); a first discharge device (3) for discharging the fine material (12) from the grinding and separating device (2); a second discharge device (4) for discharging at least a portion of the coarse material (13) from the grinding and separating device (2); a controller designed to control the processing plant (1) such that the portion of the coarse material (13) discharged via the second discharge device (4) amounts to at least 65 percent by mass of the bulk material (8) fed in; and a second separation device (20), wherein the second separation device (20) is designed to separate the discharged coarse material (13) into at least a first fraction and a second fraction, wherein particles in the first fraction have on average a smaller grain size and / or lower density than particles in the second fraction.

13. Processing plant for processing bulk material according to claim 12, wherein the grinding and separating device (2) comprises a control unit (27), wherein the control unit (27) is configured to control the proportion of the fine material (12) discharged via the first discharge device (3).

14. Use of a processing plant (1) with mill and classifier for dedusting ore, wherein the classifier is arranged above the mill and the ore is discharged from the processing plant (1) predominantly as coarse material (8) by a discharge device (4) arranged between the classifier and the mill.

15. Use of a processing plant with mill and classifier for dedusting ore according to claim 14, wherein the dedusting takes place via the discharge of fine material (12).

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