Clay calcination with inert material discharging
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- GEBR PFEIFFER SE
- Filing Date
- 2024-07-31
- Publication Date
- 2026-06-10
AI Technical Summary
In the process of preparing raw tone, inert substances are not effectively removed, leading to increased energy consumption and ecological footprint during thermal treatment, as these substances do not react and thus waste energy.
A method involving a grinding and separation process where raw tone is separated into activated fine goods and inert coarse goods, with the inert substances being enriched in the coarse goods and recycled back into the grinding process, reducing their proportion in the final product and minimizing energy expenditure during subsequent thermal treatment.
This approach reduces energy consumption and wear in the calcination system by separating inert substances from the fine goods, allowing for more efficient processing and potentially improving the quality of the final cement products.
Smart Images
Figure EP2024071681_06022025_PF_FP_ABST
Abstract
Description
[0001] Clay calcination with inert material discharge
[0002] The present invention relates to a method for processing raw clay in a processing bed, a processing plant for processing raw clay and the use of a mill-classifier combination for discharging inert materials from ground raw clay.
[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. By discharging difficult-to-grind materials, for example, the productivity of the grinding and separation device can be increased.
[0004] During raw clay processing, raw clay is typically first ground and then subjected to further treatment or use, such as calcination. DE102011014498A1 discloses a process for producing clinker additives, in which clay is calcined by thermal treatment in a kiln at a temperature of 600 to 1000 degrees Celsius. EP3909682A1 discloses a process for activating a clay mixture, in which the clay mixture is ground in a mill at a temperature of 300 to 1000 degrees Celsius. WO2021228430A1 discloses a process for separating clay raw material into fines and coarse particles using a sifter.
[0005] During calcination, the ground raw clay is heated to a predetermined temperature and thereby activated. Inert substances contained in the raw clay do not react. The energy used to heat the inert substances is thus lost. A particular object of the present invention is to reduce the inert substances in the ground raw clay and thereby reduce energy consumption during calcination and the ecological footprint.
[0006] A first aspect of the present invention comprises a method for processing raw clay in a processing plant. The method comprises feeding raw clay into a grinding and separating device, wherein the grinding and separating device comprises a grinding device and a separating device. The raw clay is then ground in the grinding device to produce ground raw clay. The ground raw clay is then separated into fines and coarse material in the separating device. The fines are discharged from the grinding and separating device. At least a portion of the coarse material is discharged from the grinding and separating device. The raw clay has a first fraction and a second fraction. The first fraction comprises activatable clay. The second fraction comprises at least one inert substance. The first fraction, in particular the activatable clay, can be enriched in the fine material.The second fraction, in particular the at least one inert substance, can be enriched in the coarse material or in the discharged coarse material.
[0007] Discharging at least a portion of the coarse material may mean discharging only a portion of the coarse material. In particular, not all of the coarse material is then discharged, but rather a portion of the coarse material is fed back into the grinding device. The portion of the coarse material not discharged can be fed back into the grinding device. The portion of the coarse material not discharged falls back onto the grinding device.
[0008] In particular, inert materials are predominantly enriched in the coarse material, whereas activatable clay is predominantly enriched in the fine material.
[0009] The second fraction, in particular the at least one inert material, may have poorer grindability than the first fraction, in particular the activatable clay. Poorer grindability means, in particular, that with the same initial grain size and grinding performance or grinding time, the resulting grain size is larger than that of fractions with better grindability. The second fraction, in particular the at least one inert material, may, on average, have larger grain sizes than the first fraction, in particular the activatable clay.
[0010] The enrichment of the first fraction, in particular the activatable clay, in the fines is determined in particular by the composition of the raw clay. The enrichment of the second fraction, in particular the at least one inert substance, in the coarse material is determined in particular by the composition of the raw clay. The enrichment of the first fraction, in particular the activatable clay, in the fines is determined in particular by the grindability of the first fraction compared to the second fraction. The enrichment of the second fraction, in particular the at least one inert substance, in the coarse material is determined in particular by the grindability of the first fraction compared to the second fraction.
[0011] The enrichment of the first fraction, in particular the activatable clay, in the fine material can be controlled, for example, by adjusting the separation device, for example, by adjusting the speed of a classifier. The enrichment of the second fraction, in particular the at least one inert substance, in the coarse material can be controlled, for example, by adjusting the separation device, for example, by adjusting the speed of a classifier.
[0012] By removing coarse material during raw clay processing, the proportion of inert materials in the ground raw clay can be reduced, thereby lowering energy consumption during subsequent calcination. Furthermore, wear and tear in the calcination plant can be reduced.
[0013] The fines may have a smaller grain size than the coarse material. The fines may, on average, have a smaller grain size than the coarse material. The particles in the fines may, especially on average, have a smaller diameter than the particles in the coarse material.
[0014] Inert materials can be defined as substances or materials that are almost chemically inert. Inert materials can be defined as substances or materials that are difficult or impossible to activate thermally. Inert materials can be defined as substances or materials that cannot be activated at a temperature of 1000 degrees Celsius. Inert materials can be defined as substances or materials that do not change at a temperature of 1000 degrees Celsius. Inert materials can have low solubility. Inert materials can be non-flammable. Inert materials in raw clay can be quartz and / or feldspar, in particular.
[0015] In particular, the inert material does not include any of the following substances: pyrite, marcasite, limestone, wood or coal.
[0016] The proportion of the first fraction, in particular the activatable clay, may be higher in the fines compared to the raw clay. The proportion of the second fraction, in particular the at least one inert substance, may be higher in the coarse material compared to the raw clay. The proportion of the first fraction, in particular the activatable clay, may be higher in the fines than in the coarse material. The proportion of the second fraction, in particular the at least one inert substance, may be lower in the fines than in the coarse material.
[0017] The fines and coarse materials can be discharged from different locations, particularly at different vertical positions, within the grinding and separating device. The fines can be discharged at the separating device or in the vicinity of the separating device. The coarse materials can be discharged between the separating device and the grinding device. The coarse materials can be discharged below the grinding device. The coarse materials can be discharged below (relative to the vertical position) the fines discharge.
[0018] The raw clay can be ground or crushed in a grinding device, especially a mill. Crushing involves, in particular, the separation of particles so that the starting particles are smaller than the input particles. Grinding can also involve the comminution of solid particles. Grinding or comminution differs significantly from deglomeration. In deglomeration, individual particles are separated, although the particles are not present in a composite and the individual particles are generally not crushed.
[0019] The grinding and separating device can be a mill-classifier combination. The grinding device can be a roller mill, a vertical roller mill, or a vertical roller mill. The separating device can be a classifier, in particular a rotary classifier.
[0020] The discharge of at least a portion of the coarse material can be carried out via a screw conveyor. The discharge of at least a portion of the coarse material can be carried out via a chute.
[0021] The proportion of coarse material removed can be between 1 mass percent and 90 mass percent, in particular between 10 mass percent and 80 mass percent of the raw clay added. The proportion of coarse material removed can be between 1 and 80 mass percent or between 10 mass percent and 90 mass percent of the raw clay added. The proportion of coarse material removed can be between 10 mass percent and 60 mass percent, in particular between 20 mass percent and 50 mass percent, in particular between 30 mass percent and 40 mass percent, of the raw clay added. The proportion of coarse material removed can be between 5 mass percent and 40 mass percent, in particular between 10 mass percent and 30 mass percent, in particular between 15 mass percent and 25 mass percent of the raw clay added. The proportion of coarse material removed can be a maximum of 90 mass percent, in particular a maximum of 80 mass percent of the raw clay added.The proportion of coarse material discharged may not exceed 20 percent by mass, in particular not exceed 15 percent by mass, of the raw clay fed in. The remaining portion of the raw clay fed in may be discharged from the grinding and separation device as fines.
[0022] The proportion of discharged coarse material may amount to at least 10 mass percent, preferably at least 30 mass percent, preferably at least 50 mass percent, of the coarse material rejected by the classifier. The proportion of discharged coarse material may amount to at least 20 mass percent, preferably at least 40 mass percent, of the coarse material rejected by the classifier.
[0023] The proportion of coarse material discharged can be between 10 mass percent and 95 mass percent, preferably between 20 mass percent and 85 mass percent, preferably between 30 mass percent and 75 mass percent, of the coarse material rejected by the classifier.
[0024] The fines can be discharged from the grinding and separation device by means of a gas stream, in particular a hot gas stream. The discharged fines can be fed to a calcining plant. In the calcining plant, the discharged fines, in particular the activatable clay present in the discharged fines, can be calcined into calcined clay powder.
[0025] The discharged fines can be calcined in the calcining plant at a temperature of 300 degrees Celsius to 1000 degrees Celsius, in particular 400 degrees Celsius to 900 degrees Celsius, in particular 550 degrees Celsius to 800 degrees Celsius.
[0026] In the calcining plant, hot gas can be used to heat the discharged fines. The hot gas used in the calcining plant can then be fed to the grinding and separation device, in particular the grinding device. This can reduce energy consumption. The hot gas can transport ground particles, in particular ground raw clay, from the grinding device, in particular in a vertical direction, to the separation device.
[0027] Hot gas can be recirculated between the grinding and separation device and the calcining system. The hot gas can be further heated during the return from the calcining system to the grinding and separation device. The hot gas can be heated in the calcining system.
[0028] The fines can be discharged from the grinding and separation device via an air stream, in particular a hot gas stream. The fines can be discharged from the grinding and separation device by the hot gas. The discharged fines can be fed to a fines separation device, also referred to as a separation device. The fines separation device can be a filter or a cyclone separator. In the fines separation device, the fines can be separated from the air stream, in particular the hot gas stream. The fines separated from the air stream can be fed to the calcining system. The remaining air stream can also be fed to the calcining system. The remaining air stream can be fed back to the grinding and separation device. Part of the remaining air stream can be fed back to the grinding and separation device, and part of the remaining air stream can be fed to the calcining system.
[0029] The calcined clay powder can be cooled after the calcination plant. The calcined clay powder, in particular the cooled calcined clay powder, can be a further processing product. A portion of the discharged coarse material, in particular of the at least one inert substance, can be added to the further processing product. The calcined clay powder can be mixed with a portion of the discharged coarse material to form a further processing product. The calcined clay powder can be the further processing product, in particular without the addition of discharged coarse material. The calcined clay powder can be mixed with a portion of the discharged at least one inert substance to form a further processing product. The proportion of calcined clay powder in the further processing product can be 5 mass percent to 99.9 mass percent, in particular 20 mass percent to 85 mass percent, in particular 35 mass percent to 70 mass percent.The proportion of calcined clay powder in the further processing product can range from 6% to 55% by mass.
[0030] The proportion of the discharged coarse material in the further processing product can be 0.1 mass percent to 95 mass percent, in particular 15 mass percent to 80 mass percent, in particular 30 mass percent to 65 mass percent.
[0031] Cement powder, cement clinker, and / or additives, in particular cement additives, may be added to the further processing product. Cement clinker and / or cement additives may be added to the further processing product.
[0032] The calcined clay powder can be mixed with cement powder, cement clinker, and / or additives, especially cement additives, to produce a further processing product. The calcined clay powder can be mixed with cement clinker and / or cement additives to produce a further processing product. The cement additives can include gypsum or granulated blast furnace slag.
[0033] The proportion of cement powder in the further processing product can be between 20 and 90 mass percent, in particular between 40 and 70 mass percent. The proportion of cement clinker in the further processing product can be between 20 and 90 mass percent, in particular between 40 and 70 mass percent. The proportion of additives in the further processing product can be between 3 and 50 mass percent, in particular between 10 and 40 mass percent.
[0034] The calcined clay can be added to concrete. The processed product can be added to concrete.
[0035] The grinding and separating device may be a first grinding and separating device.
[0036] The calcined clay powder can be fed to a second grinding and separation device. The second grinding and separation device can comprise a second grinding device and a second separation device. The further processing product can be fed to a second grinding and separation device. The calcined clay powder mixed with cement powder, cement clinker, and / or additives can be fed to a second grinding and separation device.
[0037] The calcined clay powder can be ground in the second grinding and separating device and, in particular, subsequently discharged from the second grinding and separating device.
[0038] The calcined clay powder can be ground together with cement clinker in the second grinding and separation device to form a cement mixture. The further processing product can be ground in the second grinding and separation device to form a cement mixture. The cement mixture can then be discharged from the second grinding and separation device.
[0039] The proportion of calcined clay powder in the cement mixture is, in particular, 6% to 55% by mass. However, the proportion of calcined clay powder in the cement mixture can also be 3% to 90% by mass, in particular 20% to 85% by mass, and in particular 30% to 70% by mass.
[0040] The calcined clay powder can be mixed with a portion of the discharged coarse material before the second grinding and separation device. The calcined clay powder can be mixed with a portion of the discharged coarse material in the second grinding and separation device. A portion of the coarse material discharged from the first grinding and separation device can be added to the second grinding and separation device.
[0041] The calcined clay powder can be mixed with cement powder, cement clinker, and / or additives before the second grinding and separation device. The calcined clay powder can be mixed with cement powder, cement clinker, and / or additives in the second grinding and separation device. Cement powder, cement clinker, and / or additives can be added to the second grinding and separation device.
[0042] The cement mixture can be discharged from the second grinding and separation device via a classifier. The cement mixture can be discharged from the second grinding and separation device by means of a gas stream, in particular a second gas stream, in particular a hot gas stream, in particular a second hot gas stream. The second gas stream, in particular the second hot gas stream, can be different from the hot gas stream in the first grinding and separation device. The cement mixture contained in the second gas stream can be fed to a separation device. In the separation device, the cement mixture can be removed from the second gas stream, for example, filtered. The separation device can be a filter or a cyclone separator. The second gas stream can then be returned to the second grinding and separation device, in particular the second grinding device.
[0043] The properties of the cement mixture, in particular the strength development and / or workability, can be influenced, in particular adjusted, by adding cement clinker, cement additives, and / or inert materials discharged from the first grinding and separation device to the calcined clay powder. By adding the discharged inert materials to the calcined clay powder, the quality of the calcined clay powder or the cement mixture can be controlled. The calcined clay ground in the second grinding and separation device can be added to concrete. The further processing product ground in the second grinding and separation device can be added to concrete.
[0044] The raw clay fed, in particular into the first grinding and separation device, can contain a proportion of 3 mass percent to 95 mass percent, 10 mass percent to 95 mass percent, in particular 20 mass percent to 90 mass percent, in particular 25 mass percent to 85 mass percent, in particular 40 mass percent to 75 mass percent, of activatable clay. The raw clay fed can have a proportion of 5 mass percent to 90 mass percent, in particular 10 mass percent to 80 mass percent, in particular 15 mass percent to 75 mass percent, in particular 25 mass percent to 60 mass percent, of inert materials. The inert materials can be, for example, quartz or feldspar. The inert materials can be materially unchanged at the temperature used in the calcination plant.
[0045] The fine material discharged from the first grinding and separation device can have a fineness of less than 1 millimeter, in particular less than 0.2 millimeters, in particular less than 0.1 millimeter, in particular less than 0.05 millimeters, in particular less than 0.02 millimeters. The calcined clay powder can have a fineness of less than 1 millimeter, in particular less than 0.2 millimeters, in particular less than 0.1 millimeter, in particular less than 0.05 millimeters, in particular less than 0.02 millimeters. A fineness of less than 1 millimeter can mean that 98 percent by mass of the particles have a diameter of less than 1 millimeter. This applies analogously to the other mentioned diameters of 0.2 millimeters, 0.1 millimeters, 0.05 and 0.02 millimeters.
[0046] The raw clay can be dried in the grinding and separation device. The raw clay can be dried in the grinding and separation device by the hot gas stream.
[0047] The second grinding and separation device can be designed differently from the first grinding and separation device. The second grinding and separation device can be designed identically to the first grinding and separation device.
[0048] A second aspect of the present invention comprises a processing plant for processing raw clay. The processing plant comprises a grinding and separating device. The grinding and separating device comprises a grinding device and a separating device. The grinding device is designed to grind raw clay fed into the grinding and separating device into ground raw clay. The separating device is designed to separate the ground raw clay into fines and coarse material. The processing plant further comprises a first discharge device. The first discharge device is designed to discharge the fines from the grinding and separating device. The processing plant further comprises a second discharge device. The second discharge device is designed to discharge the coarse material from the grinding and separating device. The processing plant further comprises a calcining plant.The calcining plant is designed to calcine the discharged fines into calcined fines.
[0049] The processing plant may include a controller. The controller may be configured to perform one or more method steps described in the first aspect of the invention.
[0050] The second discharge device can be designed to discharge a portion of the coarse material from the grinding and separating device. The grinding and separating device can be designed to return a portion of the coarse material, in particular the portion of the coarse material not discharged, to the grinding device.
[0051] The first discharge device can be arranged at a first location on the grinding and separating device. The second discharge device can be arranged at a second location on the grinding and separating device. The first location can be different from the second location. The first discharge device can be arranged on the separating device or in the vicinity of the separating device. The second discharge device can be arranged between the grinding device and the separating device. The term "near vicinity" means in particular that the first discharge device is arranged closer to the separating device than the second discharge device.
[0052] The grinding and separating device can be designed to dry the added raw clay.
[0053] The calcining plant can be designed and controlled to heat the discharged fine material to a temperature between 300 degrees Celsius and 1000 degrees Celsius, in particular to a temperature between 550 degrees Celsius and 800 degrees Celsius.
[0054] The processing plant, in particular the calcining plant, may comprise a control unit. The control unit may be configured to heat the calcining plant to a temperature between 300 degrees Celsius and 1000 degrees Celsius, in particular between 500 degrees Celsius and 800 degrees Celsius.
[0055] The grinding and separating device may comprise a mill-classifier combination.
[0056] The grinding device can comprise a roller mill, a vertical roller mill, or a vertical roller mill. The grinding device can have a grinding table and grinding rollers. The grinding table can be designed to be rotatable relative to the grinding rollers, so that the grinding rollers roll on a grinding track of the grinding table. The grinding device can be designed to comminute the raw clay between the grinding rollers and the grinding table. The processing plant can further comprise a first conveying device. The processing plant can further comprise a second conveying device. The processing plant can further comprise a second grinding and separation device. The first conveying device can be designed to convey the calcined fines from the calcining plant towards the second grinding and separation device.The first conveying device may be configured to convey the calcined fines from the calcining plant to the second grinding and separation device. The first conveying device may comprise a conveyor belt. The first conveying device may comprise a pipeline. The first conveying device may comprise an air conveyor trough. The first conveying device may comprise a screw conveyor. The first conveying device may comprise a chute. The first conveying device may comprise a bucket elevator.
[0057] The second conveying device can be designed to convey the discharged coarse material from the second discharge device towards the second grinding and separating device. The second conveying device can be designed to convey the discharged coarse material from the second discharge device to the second grinding and separating device. The second conveying device can comprise a conveyor belt. The second conveying device can comprise a pipeline. The second conveying device can comprise an air conveyor trough. The second conveying device can comprise a screw conveyor. The second conveying device can comprise a chute. The second conveying device can comprise a bucket elevator.
[0058] The first conveying device and the second conveying device can be brought together upstream of the second grinding and separating device. The first conveying device and the second conveying device can be guided together to the second grinding and separating device, in particular to a grinding material feed opening of the second grinding and separating device.
[0059] The processing plant may include a fines separation device. The fines separation device may be arranged between the grinding and separation device and the calcining plant. The fines separation device may comprise a filter or a cyclone separator. The fines separation device may be configured to separate fines from an air stream, in particular a hot gas stream, supplied to the fines separation device. The processing plant may be configured to feed the separated fines to the calcining plant.
[0060] The processing plant may have a hot gas circulation system. The hot gas circulation system may be configured to conduct hot gas from the calcination plant into the grinding and separation device, in particular the grinding device. The hot gas circulation system may be configured to heat the hot gas between the calcination plant and the grinding and separation device. The hot gas circulation system may be configured to conduct hot gas, in particular together with the fines, from the grinding and separation device to the calcination plant or the fines separation device.
[0061] The second grinding and separating device can comprise a second grinding device and a second separating device. The second grinding and separating device can be a mill-classifier combination. The second grinding device can be a roller mill, in particular a vertical roller mill. The second grinding device can comprise a grinding table and grinding rollers. The second grinding and separating device can be designed to grind the calcined fines. The second grinding and separating device can be designed to discharge sufficiently finely ground calcined fines from the grinding and separating device, in particular via the second separating device. The second separating device can be designed to deflect insufficiently finely ground calcined fines toward the second grinding device. The second separating device can comprise a classifier, in particular a rotary classifier.
[0062] The second grinding and separation device can have an external grinding material recirculation system. The external grinding material recirculation system can be designed to remove insufficiently finely ground calcined fines from the second grinding and separation device, in particular below the second grinding device, and to return them to the grinding and separation device, in particular together with new calcined fines.
[0063] The processing plant can further comprise a separation device. The separation device can be arranged downstream of the second grinding and separation device. The separation device can be designed to separate ground, calcined fines discharged from the second grinding and separation device from a process air stream, in particular a second hot gas stream. The processing plant can comprise a process air stream circulation system. The process air stream circulation system can be designed to conduct process air, in particular hot gas, from the second grinding and separation device to the separation device. The process air stream circulation system can be designed to conduct process air, in particular hot gas, from the separation device to the second grinding and separation device.The process air flow circulation can be designed to heat process air, in particular hot gas, between the separation device and the second grinding and separation device.
[0064] The second grinding and separation device can be designed differently from the first grinding and separation device. The second grinding and separation device can be designed identically to the first grinding and separation device. A third aspect of the present invention comprises the use of a mill-classifier combination for removing inert materials from ground raw clay. The ground raw clay is then fed to a calcining plant.
[0065] The mill-classifier combination may comprise a vertical roller mill and a classifier, in particular a rotary classifier. The classifier may be designed to separate ground raw clay into fines and coarse material. The mill-classifier combination may additionally comprise a screw conveyor or a chute for discharging a portion of the coarse material rejected by the classifier.
[0066] The ground raw clay can be calcined in the calcining plant to produce ground clay powder. The ground clay powder can be mixed with at least some of the discharged inert materials and, in particular, ground in a second mill-classifier combination.
[0067] The device according to the second aspect of the invention can be used with method steps of the method according to the first aspect of the invention. The method according to the first aspect of the invention can be carried out with a device according to the second aspect of the invention. The use of a mill-classifier combination according to the third aspect of the invention can be carried out with a device according to the second aspect of the invention or using method steps of the method according to the first aspect of the invention.
[0068] The terms "first," "second," "third," and "fourth" are to be understood merely as designations for a specific element or component and do not necessarily indicate a particular order of the components or elements mentioned. For example, the presence of a fourth element / component does not necessarily imply the presence of a first, second, or third element / component, and vice versa.
[0069] In the following, advantageous embodiments of the invention are explained in more detail with reference to the attached figures.
[0070] Figure 1 shows a schematic representation of a processing plant according to the invention for processing raw clay.
[0071] Figure 2 shows a vertical section through a grinding and separating device of a processing plant according to the invention for processing raw clay.
[0072] Fig. 1 shows a schematic representation of a processing plant 1 according to the invention for processing raw clay 2. The processing plant 1 comprises a grinding and separating device 3 in the form of a mill-classifier combination. The grinding and separating device 3 comprises a grinding device 4 in the form of a vertical roller mill and a separating device 5 in the form of a classifier. The raw clay 2 is fed into the grinding and separating device 3 via a feed opening 6. The grinding device 4 comprises grinding rollers 7 and a grinding table 8. The raw clay 2 is ground in the grinding device 4 with the aid of the grinding rollers 7 and the grinding table 8 into ground raw clay 9 and fed to the separation device 5. In the separation device 5, the ground raw clay 9 is separated into fines 10 and coarse material 11.
[0073] The fine material 10 is discharged from the grinding and separating device 3 via a first discharge device 12. A portion of the coarse material 11 is discharged from the grinding and separating device 3 via a second discharge device 13. The remaining portion of the coarse material 11 falls back onto the grinding device 4.
[0074] The fine material 10 is discharged from the grinding and separation device 3 via the first discharge device 12 by means of a hot gas stream 14. The first discharge device 12 feeds the hot gas stream 14 containing the fine material 10 to a fine material separation device 15. In the fine material separation device 15, the fine material 10 is separated from the hot gas stream 14. The fine material 10 is then fed to a calcining system 16. A portion of the hot gas stream 14 is fed to the calcining system 16 via a hot gas inlet opening 17. In the calcining system 16, the fine material 10 is calcined at a temperature of 300 degrees Celsius to 1000 degrees Celsius to form calcined clay powder 18. The calcining plant 16 comprises a control unit 19 which is designed to heat the fine material 10 in the calcining plant 16 to a temperature between 300 degrees Celsius and 1000 degrees Celsius.The calcining system 16 comprises an exhaust gas discharge device 20 through which exhaust gas 21 is discharged from the calcining system 16. The calcining system 16 comprises a hot gas outlet opening 22 through which hot gas is discharged from the calcining system 16 in the form of a hot gas stream 14 and returned to the grinding and separation device 3. A portion of the hot gas stream 14 is also returned directly from the fines separation device 15 to the grinding and separation device 3. The hot gas stream 14 from the calcining system 16 and the hot gas stream 14 from the fines separation device 15 are combined before being returned to the grinding and separation device 3.
[0075] The processing plant 1 has a heating system 23 which generates an additional hot gas stream 14 and feeds it to the grinding and separation device 3, together with the hot gas streams 14 from the calcining plant 16 and the fine material separation device 15.
[0076] The grinding and separating device 3 represents a first grinding and separating device 3. The calcined clay powder 18 is discharged from the calcining plant via a first conveyor device 48 and mixed with a portion of the coarse material 11 discharged from the first grinding and separating device 3, which is conveyed away from the first grinding and separating device 3 via a second conveyor device 49, to form a further processing product 24. The other portion of the coarse material 11 discharged from the first grinding and separating device 3 is fed to a storage facility 25, for example, an interim storage facility or a landfill. Cement clinker 26 and / or cement additives 27 can additionally be added to the further processing product 24.
[0077] The further processing product 24 is then fed via a grinding material feed opening 28 to a second grinding and separating device 29, where it is ground into cement powder 30. The second grinding and separating device 29 comprises a second grinding device 31 and a second separating device 32. The second grinding device 31 has second grinding rollers 33 and a second grinding table 34.
[0078] The processing plant 1 can comprise a third discharge device 35 and a fourth discharge device 36. The third discharge device 35 discharges sufficiently finely ground cement powder 30 from the second grinding and separation device 29 via the second separation device 32. Insufficiently finely ground cement powder 37 can be removed from the second grinding and separation device 29 via the fourth discharge device 36, added to the further processing product 24 via an external recirculation 38, and thus returned to the second grinding and separation device 29.
[0079] The sufficiently finely ground cement powder 30 is passed through a second gas stream
[0080] 39 is discharged via the third discharge device 35 and fed to a separation device 40. The second gas stream 39 can be at ambient temperature. The second gas stream 39 can be a second hot gas stream. The separation device 40 is designed to filter the cement powder 30 present in the second gas stream 39 from the second gas stream 39. The cement powder 30 is then discharged from the separation device
[0081] 40 and sent for subsequent use, for example in concrete production.
[0082] A portion of the second gas stream 39 is discharged from the processing plant 1 via a second exhaust gas discharge device 41. The other portion of the second gas stream 39 is returned to the second grinding and separation device 29. The processing plant 1 may have a second heating system 42. The second heating system 42 is designed to generate an additional second hot gas stream, which is fed together with the second gas stream 39 from the separation device 40 to the second grinding and separation device 29.
[0083] Fig. 2 shows a section of a processing plant 1 according to the invention. Essentially, Fig. 2 depicts the first grinding and separating device 3 of the processing plant 1. The second grinding and separating device 29 can be constructed identically. Raw clay 2 is added via the feed opening 6 of the grinding device 4. In the embodiment shown in Fig. 2, the grinding device 4 comprises several grinding rollers 7 and a grinding table 8. The grinding rollers 7 comminute the raw clay 2 into ground raw clay 9.
[0084] A hot gas stream 14 is introduced into the grinding and separation device 3 via an air inlet opening 43 in the lower region of the grinding device 4. The hot gas stream 14 transports sufficiently finely ground raw clay 9 from the grinding device 4 to the separation device 5. In the embodiment shown in Fig. 2, the separation device 5 is a rotary classifier. The separation device 5 comprises a vane wheel 44 driven by a motor 45. The grinding and separation device 3 further comprises a control unit 46. The control unit 46 is electronically connected to the motor 45 and is designed to control the motor 45 and thus the rotational speed of the vane wheel 44. The rotational speed of the vane wheel 44 can be continuously regulated by the control unit 46 via the motor 45. This allows the separation limit between fine material 10 and coarse material 11 to be adjusted.
[0085] Sufficiently finely ground raw clay 9 is discharged from the grinding and separation device 3 as fines 10 by the separation device 5 by means of the hot gas stream 14 via the first discharge device 12. The discharged fines 10 are fed to the fines separation device 15, the calcining system 16, or the separation device 40.
[0086] The grinding and separating device 3 further comprises a grit cone 47. Raw clay 9 that is not sufficiently finely ground, so-called coarse material 11, is deflected by the separating device 5 toward the grit cone 47. The grit cone 47 guides the coarse material 11 to the second discharge device 13. In the embodiment shown in Fig. 2, the second discharge device 13 is designed as a screw conveyor. A portion of the coarse material 11 is discharged from the grinding and separating device 3 via the second discharge device 13. The discharged coarse material 11 is fed to the feed opening 6, the storage 25, or the second grinding and separating device 29. The remaining coarse material 11 falls back to the grinding device 4.
[0087] In the embodiment of the processing plant 1 shown in Fig. 1, the second grinding and separating device 29 does not have a semolina cone 47. Furthermore, the fourth discharge device 36 is not arranged between the second grinding device 31 and the second separating device 32, as shown in Fig. 2, but is arranged below the second grinding device 31, in particular below the second grinding table 34.
Claims
CLAIMS 1. A method for processing raw clay (2) in a processing plant (1), comprising: - feeding raw clay (2) into a grinding and separating device (3), wherein the grinding and separating device (3) comprises a grinding device (4) and a separating device (5), - grinding the raw clay (2) in the grinding device (4) to ground raw clay (9), - Separating the ground raw clay (9) in the separation device (5) into fines (10) and coarse material (11), - discharging the fine material (10) from the grinding and separating device (3), and - discharging a portion of the coarse material (11) from the grinding and separating device (3), wherein the raw clay (2) has a first fraction comprising activatable clay and a second fraction comprising at least one inert substance, wherein the first fraction, in particular the activatable clay, is enriched in the fine material (10), and wherein the second fraction, in particular the at least one inert substance, is enriched in the discharged coarse material (11).
2. A method for processing raw clay according to claim 1, wherein the discharge of one part of the coarse material (11) takes place via a conveyor screw or chute.
3. A method for processing raw clay according to claim 1 or 2, wherein the proportion of the discharged coarse material (11) is between 1 mass percent and 90 mass percent, in particular between 10 mass percent and 60 mass percent, in particular between 20 mass percent and 50 mass percent, in particular between 30 mass percent and 40 mass percent, of the raw clay fed in.
4. A method for processing raw clay according to one of the preceding claims, wherein the discharged fine material (10) is fed to a calcining plant (16) and in the calcining plant (16) the discharged fine material (10), in particular the activatable clay present in the discharged fine material, is calcined to calcined clay powder (18).
5. A method for processing raw clay according to claim 4, wherein a hot gas used in the calcining plant (16) is fed to the grinding and separating device (3).
6. A method for processing raw clay according to claim 4 or 5, wherein the calcined clay powder (18) is mixed with a part of the discharged coarse material (11), in particular with the at least one inert substance.
7. A method for processing raw clay according to one of claims 4 to 6, wherein the calcined clay powder (18) is mixed with cement powder, cement clinker (26) and / or additives, in particular cement additives (27).
8. A method for processing raw clay according to any one of claims 4 to 7, wherein the calcined clay powder (18) is fed to a second grinding and separating device (29).
9. A method for processing raw clay according to one of claims 4 to 8, wherein the calcined clay powder (18) is ground in the second grinding and separating device (29) together with cement clinker (26) and / or cement additives (27) to form a cement mixture and is then discharged from the second grinding and separating device (29).
10. A method for processing raw clay according to one of the preceding claims, wherein the added raw clay (2) contains a proportion of 3 mass percent to 95 mass percent, in particular 25 mass percent to 85 mass percent, in particular 40 mass percent to 75 mass percent of activatable clay.
11. Processing plant (1) for processing raw clay (2) comprising: - a grinding and separating device (3) comprising a grinding device (4) and a separating device (5), wherein the grinding device (4) is designed to grind raw clay (2) fed into the grinding and separating device (3) into ground raw clay (9), and the separating device (5) is designed to separate the ground raw clay (9) into fines (10) and coarse material (11), - a first discharge device (12) designed to discharge the fine material (10) from the grinding and separating device (3), - a second discharge device (13) which is designed to discharge a part of the coarse material (11) from the grinding and separating device (3), - a calcining plant (16) designed to calcine the discharged fine material (10).
12. Processing plant according to claim 11, wherein the grinding device (4) is a roller mill.
13. Processing plant according to claim 11 or 12, wherein the processing plant (1) further comprises a first conveying device (48), a second conveying device (49) and a second grinding and separating device (29), wherein the first conveying device (48) is designed to convey the calcined fine material from the calcining plant (16) in the direction of the second grinding and separating device (29), wherein the second conveying device (49) is designed to convey the discharged coarse material (11) from the second discharge device (13) in the direction of the second grinding and separating device (29).
14. Use of a mill-classifier combination, comprising a vertical roller mill, a classifier, and a conveyor screw or a chute for discharging a portion of the coarse material (11) rejected by the classifier, for discharging inert materials from ground raw clay (9), wherein the ground raw clay (9) is subsequently fed to a calcining plant (16).
15. Use of a mill-classifier combination according to claim 14, wherein the ground raw clay (9) is calcined in the calcining plant (16) to calcined clay powder (18), wherein the calcined clay powder (18) is mixed with at least a portion of the discharged inert materials and is ground in a second mill-classifier combination.
16. A method for processing raw clay according to one of claims 1 to 10, wherein the discharge of the fine material (10) and the coarse material (11) takes place at different points of the grinding and separating device (3).
17. A method for processing raw clay according to one of claims 1 to 10 or 16, wherein the discharge of the fine material (10) takes place at the separation device (5) or in the vicinity of the separation device (5), wherein the discharge of the coarse material (11) takes place between the separation device (5) and the grinding device (4).
18. A process for the preparation of raw clay according to any one of claims 1 to 10, 16 or 17, wherein the fine material (10) is discharged from the grinding and separating device (3) via a first discharge device (12), wherein a part of the coarse material (11) is discharged from the grinding and separating device (3) via a second discharge device (13) and wherein the remaining part of the coarse material (11) is guided back to the grinding device (4), in particular falls back onto the grinding device (4).