System and process for the production of low-CO2 cement by staged and separate grinding

Abstract

System and method for producing low-carbon cement by classification and subsequent grinding, comprising a grinding system and a mixing system. The grinding system includes a first elevator (25), a first conveying device (26), a vertical mill (27), a first dust separator (29), and a first exhaust fan (30), which are connected sequentially. The first conveying device serves to transport materials from the first elevator to the vertical mill. The grinding system further includes a first dust separator, a ball mill (31), a second elevator (32), a separator (33), a second dust separator (34), and a conveying chute (36), which are connected sequentially.The grinding system can cause a relative mixing of the materials in opposite directions, thereby improving the mixing efficiency of the materials, and by means of the system equipped with the vertical mill and the ball mill, the comminution can be carried out according to the properties of the different components of the low-carbon cement, ensuring that all components of the low-carbon cement achieve the optimal degree of grinding, improving the performance of the cement, reducing the amount of clinker and decreasing the carbon emission intensity of the cement.

Description

TECHNICAL AREA

[0001] The present invention relates to the technical field of cement production and more specifically to a system and a method for producing low-CO2 cement by staged and separate grinding. STATE OF THE ART

[0002] In the cement industry, different materials are fed into the mixing device in a specific ratio via a metering device. Mixing is carried out mechanically or pneumatically, with uniform stirring over a specific period achieving the goal of a homogeneous mixture. Currently, commercially available mixing devices can be broadly divided into two categories: continuous and intermittent. Due to the steady material feed and long mixing time, the intermittent mixing device exhibits good mixing efficiency and high homogeneity, exceeding 99%. Compared to the pneumatic-mechanical combination mixing device, homogeneity is improved by approximately 5%.Because the intermittent mixing device requires several mixing containers with relatively large volumes for mixing and the required mixing time is long, it occupies a large footprint, has a limited production capacity and cannot be promoted and applied on a large scale.

[0003] Regarding pneumatic, mechanical, or pneumatic-mechanical combination mixing devices, the most common types of powder mixers currently available on the market are horizontal or spiral vertical mixers. The operating principle of a horizontal mixer is to mechanically stir the powder using blades mounted on the drive shaft. The fixed circular motion and axial movement of the material are the primary factors in achieving the desired mixing effect. Existing horizontal mixers generally operate at a single speed within the mixing chamber and cannot mix the material in multiple stages within the same chamber. This results in low mixing efficiency and a poor mixing result.At the same time, sufficient power is required to overcome the resistance of the material during the work process. This leads to problems such as high installed power, high energy consumption, low production efficiency, a large footprint, and low flexibility in process arrangement. When filling the mixer with material, "material overflow" and other phenomena can easily occur. The material is discharged from the mixer without being mixed, leading to large fluctuations in the uniformity of the mixture. This results in an uneven composition, impairs subsequent process design and the improvement of the performance of the final cement product, leads to a continuous increase in cement production costs, and hinders further energy savings and consumption reduction in the cement industry.

[0004] For products with similar powder particle sizes, it is not easy to separate particles of the same size during mixing to ensure uniform and smooth blending. However, for products with large differences in powder particle size, the following applies: the smaller the particle size and the finer the powder, the more likely it is to float to the surface during mixing. Conversely, the larger the particle size and the coarser the powder, the more likely it is to sink. This leads to segregation, which complicates mixing. With existing equipment, problems frequently occur during the mixing process, such as dead zones, dead spots, agglomeration, and clumping. This results in segregation and significant clumping of the product after mixing, leading to large variations in composition and a large CaO standard deviation.

[0005] In ultrafine material mixtures with a size of 1000 or 2000 mesh or more, the fineness itself is relatively small, and the gravitational constraint on the individual particles becomes so negligible that the particles exhibit a certain degree of mobility due to suspension. Simultaneously, the material absorbs a large amount of mechanical or thermal energy during the comminution process; therefore, the surface of the newly formed ultrafine particles has a very high surface energy, and the material is in an extremely unstable state.

[0006] To reduce surface energy, particles often clump together to reach a stable state, which can easily lead to particle agglomeration. Therefore, the particles tend to agglomerate with each other and are difficult to mix, making homogeneous mixing challenging.

[0007] With sticky materials, at a relative humidity above 65%, water vapor begins to condense on the surface of the particles and between the particles, and the formation of liquid bridges between the particles significantly increases the agglomeration effect.

[0008] Continuous and stable feed from the raw material storage, precise dosing, stable material transport, and uniform mixing are some of the key factors for the mixing effect. The mixer's performance is reflected in the mixing quality, energy consumption, and maintenance requirements. The main purpose of the mixing process is to obtain a mixture in which the various components are evenly distributed. The mixer's function is to blend the material uniformly. The more uniform the components of the output mixture, the better the mixing effect. In industrial applications, the feed rate of the material to be mixed can fluctuate, and the composition of the mixture output by the mixer can also vary at different times. Therefore, a well-designed, precisely dosed, and efficient mixing process system must be found.

[0009] Furthermore, the existing technology is primarily used to produce cement grades 42.5 and 32.5, and these two grades account for more than 95% of total cement production. The clinker content of 42.5 grade cement is 70% to 80%, and that of 32.5 grade cement is 60% to 70%. During cement production, clinker, gypsum, slag, limestone, and other materials are simultaneously fed into the grinding mill and ground together to a specific fineness (specific surface area of ​​320 m²). 2 / kg up to 400 m 2 / kg) ground into cement.

[0010] Cement production systems and grinding plants are technologically advanced, have clearly defined processes, and are versatile in their application. However, due to the varying grindability, hydration activity, and hydration processes of the material, the following problems arise during their use: (1) Clinker is more difficult to grind than limestone; when ground together, clinker cannot be completely ground, while limestone can be ground very finely. Because the clinker cannot be completely ground during mixed grinding, the clinker particles > 32 µm cannot be fully hydrated. To ensure the strength and other properties of the cement, the clinker utilization rate can only be increased, which leads to clinker waste, a high carbon emission intensity of the cement, and high production costs. (2) Highly active auxiliary gelling material (e.g., slag) and low-active auxiliary gelling material (e.g., limestone) are not used effectively. Since highly active auxiliary gelling material is generally more difficult to grind than clinker and low-active auxiliary gelling material is easier to grind than clinker, the difficult-to-grind, highly active auxiliary gelling material cannot be ground finely during co-grinding. This results in its activity not being fully realized and material waste. Conversely, the easily ground, low-active auxiliary gelling material is ground too finely, leading to high water consumption, poor performance, and high electricity consumption in cement production. (3) The cement particle size distribution is not ideal; the particle size distribution of conventional ground cement is narrow, which leads to a high water requirement for cement. SUMMARY OF THE INVENTION

[0011] Based on the aforementioned problems, the present invention provides a system and a method for producing low-CO2 cement through staged and separate grinding. Based on the staged and separate grinding technology, the particle size of the cement raw materials is controlled and the gelling activity is optimized to maximize the gelling activity and the ability of each cement component to undergo a synergistic activation reaction at different stages. This achieves a gradient self-excitation effect from the early to the long stage, thereby ensuring the mechanical properties of low-CO2 cement throughout its entire service life.At the same time, the present invention solves the problems of the prior art, namely unstable mixing and feeding, lack of uniformity, uneven mixing, low mixing efficiency when stirring at a single speed, high water requirement in the cement produced and poor performance.

[0012] The present invention provides a system for the production of low-CO2 cement by staged and separate grinding, comprising a grinding system and a mixing system, wherein the grinding system comprises a first bucket elevator, a first conveying device, a vertical mill, a first dust separator and a first exhaust fan connected in series, wherein the first conveying device is used to convey the material in the first bucket elevator to the vertical mill, wherein the milling system also comprises a first dust separator, a ball mill, a second bucket elevator, a classifier, a second dust separator and an air conveying trough connected in series, wherein the second dust separator is also connected to the second exhaust fan, wherein the vertical mill is also connected to a second conveying device used to convey the material to the first bucket elevator, wherein the ball mill is also connected to the third dust separator, wherein the third dust separator is connected to the third exhaust fan, wherein the third dust separator is also connected to the air conveying trough, wherein the air conveying trough is connected to a first silo, a third silo and a fourth silo, wherein the first dust separator is also connected to a second silo, wherein the first silo, the second silo, the third silo and the fourth silo are used for storing different goods, wherein the mixing system comprises a mixer, several buffer tanks and several metering devices, each of the buffer tanks being connected to a metering device, wherein the mixer comprises a housing, a feed device and a discharge opening, wherein the first silo, the second silo, the third silo and the fourth silo are each connected to a corresponding buffer tank, wherein the housing is inclined upwards from the discharge opening side to the feed device side at an angle of inclination of 2° to 10°, wherein the feed device is arranged in the upper region of the first end of the housing, and wherein the discharge opening is arranged on the side surface of the second end of the housing. wherein the metering device is connected to the feed device via a feed line, and the material from each silo is transferred via the feed line into the mixer for stirring and mixing after metering by the corresponding metering device, wherein a first agitator is arranged in the housing parallel to the housing, wherein the first agitator comprises a main shaft which is driven by a main shaft drive device, and wherein the main shaft is provided with several agitators which are mounted continuously along the axial direction of the main shaft, wherein each of the stirrers comprises two gear bevel gears and a main shaft bevel gear running coaxially to the main shaft, two gear spur gears, two large ring gears and two hollow shafts, wherein the two gear bevel gears are arranged symmetrically on both sides of the main shaft and simultaneously mesh with the main shaft bevel gears mounted and fastened on the main shaft, wherein the two gear spur gears are each arranged on the outside of their respective gear bevel gears and are each connected to the two gear bevel gears via a gear shaft, wherein the two large rims of gear are supported by a rim support cylinder, wherein the two gear spur gears are located between the two large rims of gear and each of the gear spur gears meshes with the two large rims of gear, wherein the axial direction of the rim support cylinder is parallel to the main shaft and both ends of the rim support cylinder are each attached to the side surface of the first and second ends of the mixer, wherein each of the hollow shafts is firmly connected to a large toothed ring and the two hollow shafts are closely fitted to each other at a coupling position to prevent the material from entering the stirrer, wherein each of the hollow shafts is provided with several first vanes, wherein the two hollow shafts rotate in opposite directions under the rotation of the main shaft to stir and mix the material in the housing, wherein the number of teeth of the respective main shaft bevel gear of each agitator on the main shaft is different, so that the first agitator stirs the materials at different positions in the housing at different speeds.

[0013] Alternatively, the system is also intended to include a hot air oven that supplies the entire system with hot air.

[0014] Alternatively, it is provided that the first wing has a uniform overall thickness, the first wing has a wave-like structure and is used to move the material in multiple directions at variable speeds.

[0015] Alternatively, it is provided that the first wing includes a root and a tip, wherein the tip is located at the upper end of the first wing, wherein the root is connected to the outer surface of the hollow shaft, and wherein the tip faces the output opening.

[0016] Alternatively, it is provided that the bottom and sides of the housing are also equipped with air injection devices to adjust the trajectory and dwell time of the goods in the housing.

[0017] Alternatively, it is provided that the air injection devices are connected to an air mixing chamber, wherein the air mixing chamber is connected to an air supply fan, wherein the air supply fan is used to supply the air mixing chamber with air pressure, wherein the air mixing chamber is used to supply the air injection devices with air pressure. wherein the air injection devices comprise several air inlet pipes, wherein an air inlet pipe comprises an air inlet pipe shell, a dust sealing ring, a dust deflector plate and a flap valve, wherein the air outlet connection of the air inlet pipe faces the interior of the housing, wherein the inner surface of the top of the air outlet connection is provided with a dust sealing ring and several dust deflector blades located in the center of the dust sealing ring and connected with the same pivot axis, wherein the dust deflector blades are semicircular and their diameter corresponds to the inner diameter of the dust sealing ring, wherein under the influence of air pressure the dust deflector blades are flipped up and down, wherein the air inlet port of the air inlet pipe is connected to the air mixing chamber and a flap valve is provided at a port where the air inlet port is connected to the air mixing chamber, wherein the flap valve is connected to the flap valve control, wherein the flap valve control controls the amount of air entering the air inlet pipe by controlling the pivot dimension of the flap valve.

[0018] Alternatively, the feeding device is provided for to include an input opening and an air barrier structure mounted in the input opening, wherein the airlock structure comprises an airlock housing, an airlock drive device, an airlock rotary shaft and an airlock blade, wherein the airlock rotary shaft is horizontally fixed in the input opening and is driven to rotate by the airlock drive device, wherein several airlock blades are mounted on the axial circumference of the airlock rotary shaft, wherein one end face of the airlock blade is connected to the airlock rotary shaft and the other end faces each bear against the airlock housing, wherein during feeding the airlock rotary shaft drives the airlock blades so that they rotate and convey the material into the housing, or wherein the feeding device comprises a screw feeder, wherein the screw feeder comprises a screw feeder housing and the inlet opening of the screw feeder is inclinedly attached to the screw feeder housing and is in communication with the screw feeder housing, wherein the bottom of the screw feeder housing is in communication with the interior of the housing, wherein a screw spindle and spirally distributed screw wings, which are attached to the screw spindle, are arranged vertically in the screw feed housing, wherein a grid plate is attached to the bottom of the screw spindle, the grid plate comprising several L-shaped grid bars, the L-shaped grid bars comprising vertical sides and inclined sides, the vertical sides being located above the inclined sides, one end of the inclined sides being connected to the screw spindle and the other end being connected to a lower end of the vertical sides.

[0019] Alternatively, it is provided that four first agitators are present in the housing and that the four first agitators are divided into an upper level and a lower level, with two agitators arranged on each level.

[0020] Alternatively, it is provided that several groups of locking units are distributed along the main shaft in the housing, with the locking units dividing the interior of the housing into several mixing chambers. wherein a locking unit comprises an upper locking structure and a lower locking structure arranged one above the other, wherein the upper locking structure and the lower locking structure are on the same vertical plane, wherein each locking structure comprises a lower fixed locking plate and an upper movable locking plate, with which the quantity of material in the mixing chamber is controlled that enters an adjacent mixing chamber.

[0021] Alternatively, it is provided that a guide plate is arranged on the top of each mixing chamber, the vertical height of the guide plate being complementary to the vertical distance from the top of the corresponding locking unit to the ceiling surface in the housing, the guide plate being used to further control the residence time of the material in the mixing chamber.

[0022] Alternatively, it is provided that at least one vertical agitator is provided at the top of each mixing chamber, the speed of which can be adjusted according to the mixing conditions in the mixing chamber.

[0023] The present invention also provides a method for producing low-CO2 cement by staged and separate grinding, which is carried out on the basis of the system for producing low-CO2 cement by staged and separate grinding, wherein the method comprises the following steps: Step 1. Production of desired material components for low-CO2 cement, including: an early self-activating gelling component, a medium-term self-activating gelling component, a long-term self-activating gelling component, and a rheologically active material component. wherein the early self-activating gelling component comprises silicate cement clinker, granulated blast furnace slag and grinding aids, wherein the process for producing the early self-activating gelling component is as follows: Conveying of a metered mixture of silicate cement clinker, granulated blast furnace slag and grinding aid via the first bucket elevator to the first conveying device and then through the first conveying device into the vertical mill for grinding, the material obtained in the vertical mill having a specific surface area of ​​400 m² 2 / kg - 500 m 2 / kg is collected under the action of the first exhaust fan in the first dust separator and then transported to the ball mill for further grinding, Sorting of the material by the classifier after the material has been ground again by the ball mill, the resulting material having a specific surface area of ​​1150 m² 2 / kg - 1250 m 2 / kg is collected by the second dust separator under the action of the second exhaust fan and then transported through the air conveying trough into the first silo, wherein the medium-term self-activating gelling component comprises a silicate cement clinker and a gypsum, wherein the process for producing the medium-term self-activating gelling component is as follows: Filling a metered mixture of the silicate cement clinker and the gypsum into the first bucket elevator, wherein the mixture is transferred by the first bucket elevator into the first conveying device and then transported to the vertical mill for grinding, wherein the material has a specific surface area of ​​380 m² 2 / kg up to 400 m 2 / kg is collected after grinding by the vertical mill under the action of the first exhaust fan in the first dust separator and then transferred to the second silo, wherein the long-term self-activating gelling component comprises one or more of fly ash, steel slag, furnace slag, phosphorus slag and coal grit, wherein the process for producing the long-term self-activating gelling component is as follows: Conveying a metered, long-term, self-activating, gelling component, after it has been filled into the first bucket elevator, through the first conveying device into the vertical mill for grinding, wherein after grinding the material has a specific surface area of ​​400 m² 2 / kg - 450 m 2 / kg is collected from the first dust separator under the suction action of the first exhaust fan and then transferred to the ball mill for further grinding and then through the second bucket elevator to the classifier, whereby the material obtained from the classifier has a specific surface area of ​​480 m² 2 / kg - 550 m 2 / kg is collected from the second dust separator under the action of the second exhaust fan and then transferred through the air conveying trough into the third silo, wherein the rheologically active material component is quartz sand or limestone, wherein the process for producing the rheologically active material component is as follows: Filling of the metered rheologically active material component into the first bucket elevator and subsequent conveying of the metered rheologically active material component through the first conveying device to the vertical mill for grinding, whereby after grinding the obtained material has a specific surface area of ​​200 m² 2 / kg up to 240 m 2 / kg is collected from the first dust separator under the suction action of the first exhaust fan, wherein the material collected by the first dust separator is transferred to the ball mill for further grinding and, after re-grinding in the ball mill, the material is then transferred via the second bucket elevator to the classifier, whereby the material obtained from the classifier has a specific surface area of ​​240m² 2 / kg - 300m 2 / kg is collected from the second dust separator under the action of the second exhaust fan and then transferred through the air conveying trough into the fourth silo, Step 2: Transfer of the material from each silo, after all material components have been produced, first into the appropriate buffer tank, metering of the same via the respective metering devices and subsequent feeding into the mixer for mixing and production of the desired low-CO2 cement.

[0024] Alternatively, it is envisaged that in the production of the early self-activating gelling component, the material obtained after milling by the vertical mill has a specific surface area of ​​less than 400 m². 2 The weight of the product is transported via the second conveying device back to the first bucket elevator. in the production of the medium-term self-activating gelling component, the material obtained after milling by the vertical mill has a specific surface area of ​​less than 380 m². 2 The weight of the product is transported via the second conveying device back to the first bucket elevator. in the production of the long-term self-activating gelling component, the material obtained after milling through the vertical mill has a specific surface area of ​​less than 400 m². 2 The weight of the product is transported via the second conveying device back to the first bucket elevator. in the production of the rheologically active material component, the material obtained after grinding by the vertical mill has a specific surface area of ​​less than 200 m². 2 The / kg is transported again to the first bucket elevator via the second conveying device.

[0025] Alternatively, it is envisaged that in the production of the early self-activating gelling component, the product has a specific surface area of ​​less than 1150 m². 2 / kg is fed into the ball mill for re-grinding after sorting by the classifier, where, in the production of the medium-term self-activating gelling component, the product has a specific surface area of ​​less than 480 m². 2 / kg is fed into the ball mill for re-grinding after sorting by the classifier, where, in the production of the rheologically active material component, the material has a specific surface area of ​​less than 240 m². 2 / kg is fed into the ball mill for re-grinding after sorting by the classifier.

[0026] Alternatively, it is planned that during the production of the early self-activating gelling component, the material collected by the third dust separator connected to the ball mill passes directly into the first silo via the third exhaust fan. during the production of the long-term self-activating gelling component, the material collected by the third dust separator connected to the ball mill passes directly into the third silo via the third exhaust fan, During the production of the rheologically active material component, the material collected by the third dust separator connected to the ball mill passes directly into the fourth silo via the third exhaust fan.

[0027] The present invention has at least the following advantageous effects: The mixer in the system and process for producing low-CO2 cement by staged and separate grinding according to the present invention can achieve relative disturbance of the mixed materials in opposite directions and extend the residence time of the mixture in this area by providing several sections of agitators with opposite directions of rotation. This improves the mixing performance of the mixture and reduces inefficient energy consumption. By setting a different number of conical teeth on the differential-speed agitator on the main shaft, gradient mixing is achieved along the mixing axis during the mixing process. This improves mixing efficiency and uniformity while simultaneously reducing energy consumption, improving production efficiency, and facilitating the use of large equipment.By installing a buffer tank and a dosing device upstream of the conveying system, unstable feeding can be prevented, feeding stability effectively controlled, and dosing accuracy improved. Furthermore, by implementing a system with a vertical mill and a ball mill, the various components of the low-CO2 cement can be milled separately according to their properties, ensuring that each component achieves the optimal degree of fineness. After mixing in a mixer, the resulting low-CO2 cement has an ideal particle size distribution, thus improving the cement's performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] To more clearly explain the technical solutions of the embodiments of the present invention or of the prior art, the drawings necessary for the descriptions in embodiments or of the prior art are briefly described below. Obviously, the accompanying drawings in the following description represent only some embodiments of the present invention, and other drawings can be derived from these drawings without any creative effort by the person skilled in the art. Fig. Figure 1 is a schematic representation of a system for the production of low-CO2 cement by staged and separate grinding, which is provided according to an embodiment of the present invention. Fig. Figure 2 is a schematic representation of the external shape of a mixer provided according to an embodiment of the present invention. Fig.Figure 3 is a schematic internal structural representation of a mixer provided according to an embodiment of the present invention. Fig. Figure 4 is a schematic internal structural representation of a stirrer provided according to an embodiment of the present invention. Fig. Figure 5 is a schematic internal structural representation of a stirrer provided according to an embodiment of the present invention. Fig. Figure 6 is a schematic internal structural representation of a mixer provided according to an embodiment of the present invention. Fig. Figure 7 is a schematic structural representation of an air inlet pipe provided according to an embodiment of the present invention. Fig.Figure 8 is a schematic structural representation of an airlock device provided according to an embodiment of the present invention. Fig. Figure 9 is a schematic representation of a screw feeder provided according to an embodiment of the present invention. Fig. Figure 10 is a schematic representation of a vertical agitator provided according to an embodiment of the present invention. Fig. Figure 11 is a schematic representation of a locking unit provided according to an embodiment of the present invention. Reference symbol:

[0029] 1. Housing, 2. Feeding device, 3. Dispensing opening, 3-1. Breathable filter cloth, 4. First agitator, 4-1. Main shaft, 4-2. Main shaft drive device, 4-3. Agitator, 4-3-1. Gear bevel gear, 4-3-2. Main shaft bevel gear, 4-3-3. Gear shaft, 4-3-4. Gear bearing seat, 4-3-5. Gear ring support cylinder, 4-3-6. Large gear ring, 4-3-7. Hollow shaft, 4-3-8. Gear spur gear, 5. First vanes, 6. Air mixing chamber, 6-1. Air supply fan, 7. Air inlet pipe, 7-1. Air inlet pipe shell, 7-2. Dust sealing ring, 7-3. Dust deflector blade, 7-4. Flap valve, 7-5. Flap valve control, 7-6. Air pressure sensor, 8. Air barrier housing, 9. Air barrier drive device, 10. Air barrier rotary shaft, 11. Air barrier blade, 12. Screw feeder, 12-1. Screw feeder housing, 12-2. Screw feeder inlet, 12-3. Screw spindle, 12-4. Screw flight, 12-5. Grid plate, 13. Locking unit, 13-1. Fixed locking plate, 13-2. Movable locking plate, 13-3. Upper threaded rod, 13-4.Lower threaded rod, 13-5. Drive wheel, 13-6. Bearing frame, 14. Guide plate 14, 15. Vertical agitator, 15-1. Vertical agitator drive shaft, 15-2. Vertical agitator drive, 15-3. Second vanes, 16-1. Second silo, 16-2. First silo, 16-3. Third silo, 16-4. Fourth silo, 17. Metering device, 18. Buffer tank, 19. Feed line, 20. Discharge line, 21. Uniformity monitoring system, 22. Mixer control, 23. Product storage, 24. Third bucket elevator, 25. First bucket elevator, 26. First conveying device, 27. Vertical mill, 28. Second conveying device, 29. First dust separator, 30. First exhaust fan, 31. Ball mill, 32. Second bucket elevator, 33. Sifter, 34. Second dust separator, 35. Second exhaust fan, 36. Air conveying trough, 37. Third dust separator, 38. Third exhaust fan, 39. Feed opening. DESCRIPTION OF THE EXECUTION FORMS

[0030] The technical solutions of the embodiments of the present invention are described clearly and completely below in conjunction with the accompanying drawings, which are illustrated in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all embodiments. All other embodiments that a person skilled in the art in this field would derive from the embodiments in the present invention without any creative effort are within the scope of protection of the present invention.

[0031] The system provided by the present invention for the production of low-CO2 cement by staged and separate grinding comprises a grinding system and a mixing system, the grinding system comprising a first bucket elevator 25, a first conveying device 26, a vertical mill 27, a first dust separator 29 and a first exhaust fan 30, which are connected one after the other, wherein the first conveying device 26 is used to convey the material in the first bucket elevator 25 to the vertical mill 27.

[0032] The milling system also includes a first dust separator 29, a ball mill 31, a second bucket elevator 32, a classifier 33, a second dust separator 34 and an air conveying trough 36, which are connected in series, the second dust separator 34 is also connected to the second exhaust fan 35, the vertical mill 27 is also connected to a second conveying device 28, which is used to convey the material to the first bucket elevator 25.

[0033] The ball mill 31 is also connected to the third dust separator 37, the third dust separator 37 is connected to the third exhaust fan 38, the third dust separator 37 is also connected to the air conveying trough 36.

[0034] The air conveying trough 36 is connected to the first silo 16-2, the third silo 16-3 and the fourth silo 16-4 respectively; the first dust separator 29 is also connected to the second silo 16-1; the first silo 16-2, the second silo 16-1, the third silo 16-3 and the fourth silo 16-4 serve for the storage of various goods. wherein the mixing system comprises a mixer, several buffer tanks 18 and several metering devices 17, each of the buffer tanks 18 being connected to a metering device 17 accordingly, the mixer comprising a housing 1, a feed device 2 and a discharge opening 3, the first silo 16-2, the second silo 16-1, the third silo 16-3 and the fourth silo 16-4 are each connected to the corresponding buffer tank 18, the housing 1 is inclined upwards from the discharge opening 3 towards the side of the feed device 2, with an angle of inclination of 2° to 10°, the feed device 2 is arranged in the upper part of the first end of the housing 1, the discharge opening 3 is arranged on the side surface of the second end of the housing 1.

[0035] The metering device 17 is connected to the feed device 2 via the feed line 19, and after the individual material has been metered by the metering device 17, it is fed via the feed line 19 into the mixer for stirring and mixing.

[0036] In the housing 1 a first agitator 4 is arranged parallel to the housing 1, the first agitator 4 comprises a main shaft 4-1 which is driven by a main shaft drive device 4-2, wherein the main shaft 4-1 is provided with several agitators 4-3 which are mounted continuously along the axial direction of the main shaft 4-1.

[0037] Each agitator 4-3 comprises two gear bevel gears 4-3-1 and a main shaft bevel gear 4-3-2 coaxial with the main shaft 4-1, two gear spur gears 4-3-8, two large gear rings 4-3-6 and two hollow shafts 4-3-7, wherein the two bevel gears 4-3-1 are arranged symmetrically on both sides of the main shaft 4-1 and simultaneously mesh with the main shaft bevel gears 4-3-2 mounted and fastened on the main shaft 4-1, wherein the two spur gears 4-3-8 are each arranged on the outside of their corresponding bevel gears 4-3-1 and are each connected to the two bevel gears 4-3-1 via a gear shaft 4-3-3, the two large rims 4-3-6 are supported by the rim support cylinder 4-3-5, the two spur gears 4-3-8 are located between the two large rims 4-3-6, and each spur gear 4-3-8 engages in the two large rims 4-3-6, wherein the axial direction of the rim support cylinder 4-3-5 is parallel to the main shaft 4-1 and both ends of the The toothed ring support cylinders are attached to the side surface of the first and second ends of the mixer.

[0038] Each hollow shaft 4-3-7 is rigidly connected to a large gear ring 4-3-6, the two hollow shafts 4-3-7 being closely fitted to each other at a coupling position to prevent the material from entering the stirrer 4-3, each of the hollow shafts 4-3-7 being provided with several first vanes 5, the two hollow shafts 4-3-7 rotating in opposite directions under the rotation of the main shaft 4-1 to stir and mix the material in the housing 1, wherein the number of teeth of the respective main shaft bevel gear 4-3-2 of each agitator 4-3 on the main shaft 4-1 is different, so that the first agitator 4 agitates the materials at different positions in the housing 1 at different speeds.

[0039] Specifically, the first conveying device 26 transports the materials mainly from the first bucket elevator 25 to the vertical mill 27, while the second conveying device 28 mainly transports the unsuitable materials ground in the vertical mill 27 back to the first bucket elevator 25 and sends them, along with the unground raw materials, to the vertical mill 27 for re-grinding. In exemplary embodiments of the present invention, both the first conveying device 26 and the second conveying device 28 are adhesive tape machines characterized by high efficiency, continuity, strong adaptability, economy, practicality, safety, and reliability. Furthermore, in the present invention, an exhaust fan is provided at the rear end of each dust collector to allow the ground powder and exhaust gases to easily enter the dust collector, enabling the powder to be collected.At the same time, the fan can also adjust the wind speed and air volume as needed to adapt the corresponding dust collector at different stages so that it collects goods with different specific surfaces.

[0040] As in Fig.As shown in Figure 1, different manufactured goods are delivered to separate silos, and each silo corresponds to a buffer tank 18 and a metering device 17. Each silo is set to a specific volume according to the requirements of the mixed material production. A specific quantity of material is released from the silo and stored in the buffer tank 18. The buffer tank 18 is a small storage unit with a specific volume, smaller than the corresponding silo. The metering device 17 is connected to the buffer tank 18, and the material in the buffer tank 18 is fed into the metering device 17 at a stable rate according to the delivery rate determined by the metering device 17.Various goods are fed in specific quantities via the metering device 17 into the feed line 1, which is connected to the feed device, and then conveyed through the feed line 19 from the feed device 2 in the upper part of the first end of the housing 1 into the mixing chamber 1. After stirring, the mixture flows out of the dispensing opening 3 on the side surface of the second end of the housing 1. Each good is independently equipped with a multi-stage uniform mixing system, which allows different goods to be mixed as needed and offers a high degree of ease of operation. In the present application, the metering device is designed as a rotor scale and is more preferably designed as a double-layer rotor scale to ensure that the metering accuracy is within ±0.5%. The volume of the buffer tank 18 is set to 2 to 5 times the maximum measuring range of the scale.

[0041] As in Fig.As shown in Figure 2, the housing 1 is inclined upwards from the discharge opening 3 towards the side of the feed device 2, at an angle of inclination of 2° to 10°, so that the material moves as a whole towards the discharge side under the influence of gravity, thereby reducing the discharge resistance. Furthermore, the angle of inclination should be neither too small nor too large. If it is too small, problems may occur during discharge, while an angle that is too large results in the material being mixed too briefly in the housing 1 and exiting the discharge opening 3 unevenly.

[0042] An opening is provided at the top of the housing of the dispensing opening 3, which is covered with a breathable filter cloth 3-1 to ensure a uniform flow of the material within the housing 1 and simultaneously prevent the material from overflowing from the opening. The mixing housing 1 is supported by a base support device, and several glass observation doors are also provided on the side of the housing 1 to allow observation of the mixing state and the path of the material being mixed. In the present application, the mixing capacity is 1.0 to 2.0 times the mixing quantity.

[0043] As in Fig. 3, Fig. 4 and Fig.As shown in Figure 5, a first agitator 4 is provided in and parallel to the housing 1. The first agitator 4 comprises a main shaft 4-1, both ends of which are mounted on two end faces in the longitudinal direction of the housing 1. Each main shaft 4-1 is driven independently by a main shaft drive device 4-2. The main shaft drive device 4-2 comprises a drive motor and a coupling, the drive motor being a permanent magnet motor. The permanent magnet motor in the present application is a reversing motor that can rotate forwards and backwards to prevent feed blockage.

[0044] The main shaft drive device 4-2 is arranged on the outside of one end of the housing 1 facing the feed device 2. The head end of the main shaft 4-1 is connected to the main shaft drive device 4-2, and the tail end of the main shaft 4-1 is supported by a bearing located at the other end of the mixing housing 1. The bearing is secured to the mixing housing 1 by the bracket. Each main shaft 4-1 is provided with several agitators 4-3, which are mounted continuously along the axial direction of the main shaft 4-1. The two bevel gears 4-3-1 in the agitator 4-3 are arranged symmetrically on both sides of the main shaft 4-1 and simultaneously engage with the main shaft bevel gear 4-3-2, which is mounted on the main shaft 4-1. The main shaft bevel gear 4-3-2 is tapered and is mounted on the main shaft 4-1.The gear mesh drives the bevel gear 4-3-1, which has a specific number of teeth, to rotate radially. The two spur gears 4-3-8 are each located on the outside of their corresponding bevel gears 4-3-1 and are each connected to the two bevel gears 4-3-1 via a gear shaft 4-3-3. The spur gears 4-3-8 are connected to the ring support cylinder 4-3-5 via the gear bearing seat 4-3-4. The two large ring gears 4-3-6 are supported by the ring support cylinder 4-3-5, the two spur gears 4-3-8 are located between the two large ring gears 4-3-6, and each spur gear 4-3-8 engages with the two large ring gears 4-3-6.The gear support cylinder 4-3-5 runs parallel to the main shaft 4-1, and its two ends are each attached to the side surfaces of the first and second ends of the mixer. The two large gear rings 4-3-6, which mesh with the two spur gears 4-3-8, are attached in the outer circumferential direction of the gear support cylinder 4-3-5. The side surfaces of the first end and the second end are both vertical surfaces.

[0045] Each hollow shaft 4-3-7 is rigidly connected to a large gear ring 4-3-6, with the two hollow shafts 4-3-7 being closely matched at a coupling position to prevent the material from entering the agitator 4-3. Several first vanes 5 are arranged on the outside of each hollow shaft 4-3-7. As the main shaft 4-1 rotates, the two hollow shafts 4-3-7 rotate in opposite directions around the main shaft 4-1, driving the first vanes 5 on the two hollow shafts 4-3-7 in opposite directions, thereby stirring and mixing the material in the housing 1.The number of teeth on the main shaft bevel gear 4-3-2 of each stirrer 4-3 on the main shaft 4-1 is different; by setting different numbers of teeth on the main shaft bevel gear 4-3-2, the transmission speed is also different when the main shaft bevel gear 4-3-2 is used for transmission, so that the first stirrer 4 can stir the material at different positions in the housing 1 at variable speed.

[0046] Each agitator 4-3 comprises first blades 5 rotating in opposite directions, which generate a more complex and intense liquid movement during the stirring process. This improves the mixing effect of the material in the housing 1, ensuring that the material is thoroughly mixed in all directions, reducing dead mixing angles, and improving mixing uniformity. Furthermore, due to their opposing directions of rotation, they can cooperate to form a more efficient stirring force field, which accelerates the flow and mixing of the material in the mixing drum. This shortens the mixing time and improves production efficiency.

[0047] Several agitators 4-3 are mounted on the main agitator shaft 4-1, each rotating in a different direction. Within a specific mixing zone, this not only creates a relative disturbance of the mixture in opposite directions but also extends the residence time of the mixture within that zone, thereby improving the mixing performance and reducing inefficient energy consumption. Furthermore, the agitation speeds of the multiple agitators 4-3, which are continuously mounted on the main shaft 4-1, vary. The agitators 4-3 with different numbers of conical teeth mix the mixture more effectively and uniformly. This design with varying agitation speeds increases the contact area and contact time between the materials, promotes interaction and diffusion, and thus improves mixing efficiency.Furthermore, gradient stirring allows the material in mixing chamber 1 to be exposed to different mixing environments and conditions, thus more comprehensively meeting mixing requirements. By gradually increasing the number of conical teeth on the agitator 4-3, the transition from coarse to fine mixing can be achieved, allowing the material to gradually reach a uniform mixing state. This contributes to improved mixing quality and makes the product more stable and reliable. By gradually increasing the number of conical teeth on the agitator 4-3, different mixing effects can be achieved at various stages, thereby avoiding unnecessary energy consumption, which contributes to lower production costs and improved economic benefits.

[0048] In summary, the mixer in the system and process for producing low-CO2 cement by staged and separate grinding according to the present invention can achieve relative disturbance of the mixture in opposite directions and extend the residence time of the mixed materials in this area by providing several sections of agitators with opposite directions of rotation. This improves the mixing performance of the mixture and reduces inefficient energy consumption. By setting a different number of conical teeth on the differential-speed agitator on the main shaft, gradient mixing is carried out along the mixing axis during the mixing process. This improves mixing efficiency and uniformity while simultaneously reducing energy consumption, improving production efficiency, and facilitating the use of large equipment.Furthermore, installing a buffer tank and a dosing device upstream of the conveying system prevents unstable feeding, effectively controls feeding stability, and improves dosing accuracy. Additionally, by incorporating a vertical mill and a ball mill into the system, the various components of the low-CO2 cement can be milled separately according to their properties, ensuring that each component achieves the optimal degree of fineness. After mixing in a mixer, the resulting low-CO2 cement has an ideal particle size distribution, thus improving the cement's performance.

[0049] In one possible embodiment, a hot air oven is also included to supply the entire system with hot air.

[0050] The system also includes a hot air oven that supplies the grinding production line with hot air. This hot air is primarily used for drying the material. In staged and separate cement grinding, the material typically needs to be dried to remove excess moisture and ensure a smooth grinding process. The hot air provided by the oven effectively meets this need, improving the efficiency and effectiveness of the drying process.

[0051] In one possible embodiment, the first wing is provided to have a uniform overall thickness, the first wing has a wave-like structure and is used to move the material in multiple directions at variable speeds.

[0052] Specifically, the first blade 5 has a uniform thickness and a corrugated structure. For example, if several corrugated blades are mounted on the agitator shaft and the blades rotate with the main shaft 4-1, eddy currents and shear forces are generated, causing the material to move at varying speeds in multiple directions. As the corrugated blades rotate, they continuously change their contact area and direction with the material. This constantly changing contact generates a shear force that pushes and mixes the material in a direction perpendicular to the rotating shaft. Furthermore, the rotation of the blade subjects the material to centrifugal force, which pushes it outwards. The combined effect of the centrifugal force and the shear force causes the material to move at varying speeds in multiple directions.As the blade rotates, the material circulates under the blade's pressure, forming vortices. These vortices create turbulence and mixing within the material, contributing to a more uniform mixing and distribution.

[0053] In one possible embodiment, the first wing is provided to include a root and a tip, wherein the tip is located at the upper end on the first wing, wherein the root is connected to the outer surface of the hollow shaft, and wherein the tip faces the output opening.

[0054] Specifically, the root of the first blade 5 is connected to the outer surface of the hollow shaft 4-3-7, and the tip of the blade points towards the discharge opening 3, causing the material to tend to flow towards the discharge opening 3 during the stirring process. In the present invention, the angle between the first blade 5 and the axis of the hollow shaft 4-3-7 is 30° to 60°.

[0055] In one possible embodiment, the bottom and sides of the housing are also provided with air injection devices to adjust the trajectory and residence time of the goods in the housing.

[0056] Specific features are, as in Fig.Figure 3 shows that the bottom and side of the mixing chamber 1 are equipped with air injection devices to achieve a repeated movement path for the material during the ascent and settling process. This ensures that the material is thoroughly mixed and stirred during this process, and that the path and residence time of the material in the chamber 1 can be adjusted. By adjusting the air injection devices, the repeated movement path of the material during the ascent and settling process can be achieved, allowing the material to be thoroughly mixed and stirred. The air injection device creates a convection effect and dispersion of the material within the chamber 1, which means that, in particular, finer materials are subjected to forces from different directions within the movement area, thus enabling the material to be thoroughly stirred and mixed.At the same time, local deposition of the lower material can be prevented, the uniformity of the material mixture improved, and the standard deviation of the mixing effect reduced.

[0057] In one possible embodiment, the air injection devices are connected to an air mixing chamber, which is used to supply the air injection device with air pressure. wherein the air injection devices comprise several air inlet pipes, wherein an air inlet pipe comprises an air inlet pipe shell, a dust sealing ring, a dust deflector plate and a flap valve, wherein the air outlet connection of the air inlet pipe faces the interior of the housing, wherein the inner surface of the top of the air outlet connection is provided with a dust sealing ring and several dust deflector blades located in the center of the dust sealing ring and connected with the same pivot axis, wherein the dust deflector blades are semicircular and their diameter corresponds to the inner diameter of the dust sealing ring, wherein under the influence of air pressure the dust deflector blades are flipped up and down, wherein the air inlet port of the air inlet pipe is connected to the air mixing chamber and a flap valve is provided at a port where the air inlet port is connected to the air mixing chamber, wherein the flap valve is connected to the flap valve control, wherein the flap valve control controls the amount of air entering the air inlet pipe by controlling the pivot dimension of the flap valve.

[0058] What is specific is how in Fig. 6 and Fig.Figure 7 shows the air injection device connected to the air mixing chamber 6. The air mixing chamber 6 is connected to the air supply fan 6-1, and the air supply fan 6-1 is used to supply the air mixing chamber 6 with compressed air. The air mixing chamber 6 supplies the compressed air provided by the air supply fan to the air injection device. The air injection device comprises several air inlet pipes 7, and each air inlet pipe 7 comprises an air inlet pipe shell 7-1, a dust sealing ring 7-2, a dust deflector plate 7-3, and a flap valve 7-4. The air outlet port of the air inlet pipe 7 faces the inside of the housing 1. A dust sealing ring 7-2 is arranged on the upper inner surface of the air outlet port. Several dust deflector plates 7-3, connected by the same pivot axis, are also arranged in the center of the dust sealing ring 7-2.The dust control blades 7-3 are semicircular and their diameter corresponds to the inner diameter of the dust sealing ring 7-2; under the influence of air pressure, the dust control blades 7-3 can be turned up and down.

[0059] The air inlet port of the air inlet pipe 7 is connected to the air mixing chamber 6, and a flap valve 7-4 is provided at the port where the air inlet port connects to the air mixing chamber 6. The flap valve 7-4 is electrically connected to the flap valve control unit 7-5. The air inlet pipe 7 is also equipped with an air pressure sensor 7-6, which is electrically connected to the flap valve control unit 7-5 and detects the air volume in the air inlet pipe 7 and feeds it back to the flap valve control unit 7-5. The flap valve control unit 7-5 controls the pivot point of the flap valve 7-4 according to the air volume supplied to the air inlet pipe 7, thus ensuring that the air volume in the air inlet pipe 7 reaches the target air volume. The gas in the air mixing chamber 6 is ambient air; preferably, it can also be hot air at a specific temperature to improve mixing of the air and the material.

[0060] In one possible embodiment, the feeding device includes an input opening and an air barrier structure mounted in the input opening. wherein the airlock structure comprises an airlock housing, an airlock drive device, an airlock rotary shaft and an airlock blade, wherein the airlock rotary shaft is horizontally fixed in the input opening and is driven to rotate by the airlock drive device, wherein several airlock blades are mounted on the axial circumference of the airlock rotary shaft, wherein one end face of the airlock blade is connected to the airlock rotary shaft and the other end faces each rest against the airlock housing, wherein during feeding the airlock rotary shaft drives the airlock blades so that they rotate and convey the goods into the housing.

[0061] More precisely, as in Fig.As shown in Figure 6, the feed device 2 is located on the upper part on one side of the housing 1, and an airlock device is provided in the input opening of the feed device 2. As shown in Fig.As shown in Figure 8, the airlock device is cylindrical, and the airlock rotary shaft 10 in the airlock device is located inside the inlet opening and is arranged horizontally. The airlock drive device 9 is located outside the inlet opening housing and is connected to the airlock rotary shaft 10 to drive the airlock rotary shaft 10 to rotate it.The material enters the airlock chamber through the inlet opening. The airlock rotating shaft 10 is perpendicular to the main shaft 4-1, with one end connected to the airlock drive device 9 and the other end attached to the side of the airlock device housing. The airlock blade 11 is fixed axially to the airlock rotating shaft 10. One end face of the airlock blade 11 is connected to the airlock rotating shaft 10, while the other end faces of the airlock blade 11 rest against the airlock housing 8. This means that the gaps between the other end faces of the airlock blades 11 and the airlock housing 8 are extremely small, and the end faces can rotate freely relative to the airlock housing 8. Driven by the airlock drive device 9, the airlock rotating shaft 10 rotates.During feeding, the air barrier shaft 10 rotates to drive the air barrier blades 11 and convey the material into the housing 1. Simultaneously, the air barrier blades 11 also prevent outside air from entering the housing 1 and affecting the airflow distribution within the housing. The minimum distance between the air barrier blade 11 and the air barrier housing 8 is 5 to 10 mm.

[0062] The feeding device includes a screw feeder.

[0063] The screw feeder comprises a screw feeder housing, the input opening is attached at an angle to the screw feeder housing and the input opening is in communication with the screw feeder housing, with the bottom of the screw feeder housing being in communication with the inside of the housing. wherein a screw spindle and spirally distributed screw wings, which are attached to the screw spindle, are arranged vertically in the screw feed housing, wherein a grid plate is attached to the bottom of the screw spindle, the grid plate comprising several L-shaped grid bars, the L-shaped grid bars comprising horizontal sides and vertical sides, and the vertical sides being located above the horizontal sides, one end of the horizontal side being connected to the screw spindle and the other end being connected to the vertical side.

[0064] Specifically, the feeding device 2 comprises, as shown in Fig.Figure 9 shows a screw feeder 12. The inlet opening 12-2 of the screw feeder is attached obliquely to the screw feeder housing 12-1 and communicates with the housing of the screw feeder 12. The counterclockwise angle between the inlet opening 12-2 of the screw feeder and the horizontal plane is 45 to 80 degrees. The base of the screw feeder housing 12-1 is embedded in the interior of the housing 1 and communicates with the interior of the housing 1. After the material is fed from the outside through the inlet opening 12-2 of the screw feeder, it enters the screw feeder 12 and from there passes into the housing 1 of the mixer.

[0065] A screw feed spindle 12-3 is arranged vertically in the screw feed housing 12-1, and the screw flights 12-4 are attached to the screw feed spindle 12-3. The screw flights 12-4 are arranged spirally around the screw feed spindle 12-3, and the minimum distance between the edge of the screw flights 12-4 and the screw feed housing 12-1 is 5 to 10 mm. This ensures that the screw flights 12-4 rotate normally and effectively prevents wind from entering the housing, which would impair the distribution of the airflow in the housing 1 and the mixing effect. Furthermore, the path of the material entering from the feed opening can also be directed.A grid plate 12-5 is fixed to the base of the screw feeder spindle 12-3. The grid plate 12-5 comprises several L-shaped grid bars with inclined and vertical sides. The vertical sides are located above the inclined sides. One end of each inclined side is connected to the screw feeder spindle 12-3, and the other end is connected to the lower end of each vertical side. All inclined and vertical sides together form a cylindrical shape. The diameter of this cylindrical shape is larger than that of the screw feeder housing 12, ensuring that the material entering the housing 1 from the screw mechanism must pass through the grid plate 12-5. The screw feeder spindle 12-3 is connected to the drive motor. Driven by the drive motor, the screw feeder spindle 12-3 rotates, thus driving the screw flights 12-4 and the grid.During rotation, the grid crushes the material that is guided downwards along the screw wings 12-4.

[0066] In one possible embodiment, it is provided that four first agitators are present in the housing and that the four first agitators are divided into an upper level and a lower level, with two agitators arranged on each level.

[0067] Specific features are, as in Fig.Figure 6 shows four parallel first agitators 4 provided in the housing 1, divided into an upper and a lower level, with two agitators on each level to stir the material at different heights within the housing 1. In other embodiments, different numbers of first agitators 4 may be provided according to the actual mixing requirements. In other embodiments, the two shafts of the upper level are the main shafts 4-1, and two auxiliary shafts are provided on the lower level. The diameters of the two main shafts 4-1 are larger than those of the two auxiliary shafts, and the diameters of the corresponding multi-stage differential speed agitator 4-3 and the vortex impeller blades are also larger than those of the auxiliary shafts. The diameter of the main shaft 4-1 is 2 to 5 times the diameter of the auxiliary shaft.

[0068] In one possible embodiment, it is provided that several groups of locking units are distributed along the main shaft in the housing, the locking units dividing the interior of the housing into several mixing chambers, wherein a locking unit comprises an upper locking structure and a lower locking structure arranged one above the other, wherein the upper locking structure and the lower locking structure are on the same vertical plane, wherein each locking structure comprises a lower fixed locking plate and an upper movable locking plate, with which the quantity of material in the mixing chamber is controlled that enters an adjacent mixing chamber.

[0069] Specific features are, as in Fig.Figure 6 shows several groups of locking units 13 provided inside the housing 1. These groups of locking units 13 divide the interior of the housing 1 into several compartments, each compartment being considered a mixing chamber. The locking unit 13 consists of two locking structures: an upper locking structure and a lower locking structure, located on the same vertical plane. Each level of locking plates consists of two parts: a fixed locking plate 13-1 and a movable locking plate 13-2. The mixing volume and residence time of each mixing chamber are controlled by adjusting the position of the movable locking plate 13-2. The locking unit 13 is made of wear-resistant material. In this embodiment, the base material is cast steel ZG20SiMn, and the wear-resistant layer consists of weld overlay material. Furthermore, the top of each locking unit can also be adjusted to a louvered shape, i.e.,A baffle with multiple gaps allows the material to pass only through the gaps, thus preventing the material from overflowing too quickly and reducing the mixing residence time.

[0070] The volume of the housing is determined based on the feed quantity of the material, the bulk density and the number of cycles; the calculation formula is as follows: V=k×1000×Pρ0

[0071] In formula (1), V is the volume of the housing, the unit is m³. 3 , P is the feed rate of the material, the unit is t / h, p0 is the bulk density of the mixture, the unit is kg / m³ 3 , and k is the number of cycles.

[0072] Specifically for goods with a particular ratio over a longer period, the volume of the housing 1 can be adjusted according to the bulk density of the mixed material, the feed rate per hour, and the number of stirring cycles of the material in the housing 1. By appropriately designing the volume of the housing 1, and assuming a homogeneous mixture, unnecessary space requirements and additional costs can be reduced. The number of cycles k is adjusted according to the required accuracy of the product after mixing; preferably, the number of cycles k is 1 to 5, and the length-to-diameter ratio of the housing 1 is set to 2 to 10.

[0073] In one possible embodiment, a guide plate is arranged on the top of each mixing chamber, the vertical height of the guide plate being complementary to the vertical distance from the top of the corresponding locking unit to the ceiling surface in the housing, the guide plate being used to further control the residence time of the material in the mixing chamber.

[0074] Specifically, as in Fig.As shown in Figure 3, the locking unit 13 divides the interior of the housing 1 into several mixing chambers, and a guide plate 14 is provided on the top of each mixing chamber. Each guide plate 14 is complementary to the vertical distance from the top of the corresponding locking unit 13 to the ceiling surface in the housing 1. The corresponding locking unit 13 is located downstream in the material input direction, and the vertical height of the guide plate 14 closest to the output opening 3 can be complementary to the locking unit 13 located upstream in the material input direction.By adjusting the guide plate 14, the time required for the material to travel from the current mixing chamber to the downstream mixing chamber is also controlled. This increases the residence time of the material in the mixing chamber and ensures that the material entering the housing 1 is completely mixed before flowing out of the discharge opening 3. In other embodiments, several separating strips are provided on the inner wall of the housing 1 along the stirring direction of the main shaft 4-1. If the locking unit 13 is missing or the bottom and sides of the housing are not equipped with air injection devices, the inner wall of the housing 1 is provided with several separating strips along the stirring direction of the main shaft 4-1. The positions of the separating strips in the housing 1 are opposite the projection positions of the connection point of each pair of agitators 4-3 on the side wall of the housing 1.The side surface of the separating strip facing the feed device 2 is an inclined surface, and the side surface of the separating strip facing the output opening 3 is a vertical surface. The vertical surface serves to prevent backflow of the material towards the side of the feed device 2.

[0075] In one possible embodiment, at least one vertical agitator is provided on the top of each mixing chamber, the rotational speed of the vertical agitator being adjustable according to the mixing conditions in each mixing chamber.

[0076] Specifically, they include, as in Fig. 6 shows that in the mixing chamber formed by each barrier unit 13, the upper and lower levels contain at least four agitators 4-3, and the four agitators 4-3 belong to different first agitators 4.

[0077] A vertical agitator 15 is provided at the top of the mixing chamber to achieve further gradient-like stirring of the material in the mixing chamber in a vertical direction. The stirring speed of the corresponding vertical agitator 15 in each mixing chamber can be adjusted according to the actual mixing conditions.

[0078] The vertical agitator comprises a vertical agitator rotating shaft, a vertical agitator drive, and several secondary vanes distributed around the circumference of the vertical agitator rotating shaft.

[0079] A second blade comprises two vertical sides and is connected to the rotating shaft of the vertical agitator via one of the vertical sides; a vertical curved surface is present between the two vertical sides; the drive of the vertical agitator is located outside the top surface of the housing and is connected to the upper end of the rotating shaft of the vertical agitator; the vertical agitator drives the rotating shaft of the vertical agitator, causing the second blade to rotate in a horizontal direction.

[0080] What is specific is how in Fig.Figure 10 shows a rotating shaft 15-1 of the vertical agitator arranged vertically within the vertical agitator 15, and several second blades 15-3 are arranged around the circumference of the rotating shaft 15-1 of the vertical agitator. A second blade 15-3 is a vertically arranged curved surface, one vertical side of which is connected to the rotating shaft 15-1 of the vertical agitator. The drive 15-2 of the vertical agitator is located outside the top surface of the housing 1 and is connected to the upper end of the rotating shaft 15-1 of the vertical agitator. Under the action of the drive 15-2 of the vertical agitator, the rotating shaft 15-1 of the vertical agitator drives the second blades 15-3, causing the second blades to rotate and agitate the material located at the top of the housing 1 in a horizontal direction.

[0081] The upper end of the underlying fixed locking plate is provided with two projections, and the two main shafts pass through the fixed locking plate; the bottom of the upper movable locking plate is provided with a groove that is complementary to the shape of a projection, the width of the groove being greater than the diameter of the main shaft.

[0082] The movable locking plate in the upper locking structure is connected to the cover plate of the housing via the upper threaded rod, and the movable locking plate in the lower locking structure is connected to the upper plate of the housing via the lower threaded rod; the upper and lower threaded rods drive the corresponding movable locking plates so that they move vertically up and down.

[0083] Specifically, the blocking unit comprises 13, as in Fig. 6 and Fig.Figure 11 shows two locking structures arranged one above the other, each locking structure comprising an upper movable locking plate 13-2 and a lower fixed locking plate 13-1. The two main shafts 4-1 pass through the fixed locking plate 13-1, and two projections are provided on the upper end of the fixed locking plate 13-1. The sides of the upper and lower locking structures of the fixed locking plates 13-1 lie close to the inner wall of the housing 1. The lower end face of the fixed locking plate 13-1 in the lower locking structure is in close contact with the bottom surface of the housing 1, thus preventing the material from passing through the gap between the fixed locking plate 13-1 in the lower locking structure and the bottom of the housing 1 without being sufficiently mixed.The underside of the movable locking plate 13-2, which corresponds to the fixed locking plate 13-1, is provided with a groove whose shape is complementary to the projection on the corresponding fixed locking plate 13-1. The width of the groove is greater than the diameter of the main shaft 4-1, and the movable locking plate 13-2 can be moved into a position adjacent to the corresponding fixed locking plate 13-1, with the two grooves of the movable locking plate 13-2 each engaging with the two main shafts 4-1. At this point, the ability of the material in the mixing chamber to block its passage into other mixing chambers is minimal. When the groove of the movable locking plate 13-2 is fully aligned with the projection of the corresponding movable locking plate 13-1, the blocking effect on the material is maximized, thereby increasing the residence time of the material in the mixing chamber. In the present application, the overall height of each locking plate is less than the height of the mixing housing 1.

[0084] In the locking unit 13, the movement of the movable locking plate 13-2 of the upper locking structure is achieved by an upper threaded rod 13-3, which is mounted on the top plate of the housing 1, and the movement of the movable locking plate 13-2 of the lower locking structure is achieved by a lower threaded rod 13-4, which is mounted on the top plate of the housing 1. The upper ends of the upper and lower threaded rods 13-4 pass through the corresponding drive wheel 13-5 on the outside at the upper end of the housing 1. A bearing frame 13-6 is provided between the drive wheel 13-5 and the outer surface at the upper end of the housing 1 to support the drive wheel 13-5. By rotating the drive wheel 13-5, the corresponding threaded rod is moved vertically upwards or downwards, and the threaded rod moves the corresponding movable locking plate 13-2 vertically upwards and downwards, thereby regulating the residence time of the material in the mixing chamber.

[0085] The floor area of ​​the mixing chamber is evenly divided into four "field"-shaped areas; the maximum time interval Δt between the blowing processes of the air injection device in two adjacent areas in the lower part of the mixing chamber is calculated as follows: Δt=2hg

[0086] In formula (2), h is the height of the barrier unit between the mixing chamber and the next mixing chamber along the material conveying direction, and g is the acceleration due to gravity, which is 9.8 m / s². 2 amounts.

[0087] Specifically, the floor of each mixing chamber is divided into four equally sized, field-shaped areas, with a time interval Δt for bubbles between any two adjacent areas. Within these four areas of the floor, the material is simultaneously subjected to different pressures, resulting in varying falling velocities. This process can increase the probability of mixing and enhance the mixing effect. Furthermore, the amount of air injected can be reduced while maintaining the same mixing effect. In equation (2), h is the height of the barrier unit between the mixing chamber and the next mixing chamber along the material conveying direction, and the height of the barrier unit of the mixing chamber closest to the discharge opening is based on the height of the barrier unit between the mixing chambers adjacent to the mixing chamber.

[0088] The minimum blowing force of the mixer is greater than the weight of the heaviest item in the mixture.

[0089] Specifically, the minimum blowing force of the mixer is greater than the weight of the heaviest item in the mixture to ensure that every item can be blown and that no dead corner forms at the bottom of the mixing chamber during mixing, thus further promoting the mixing of the material.

[0090] The mixer in the mixing system also includes a uniformity detection system. This system is located at the discharge line to detect the uniformity of the material exiting the mixer. The uniformity detection system is electrically connected to the mixer control unit. It is used to detect the uniformity of the components of the mixture and to report the detected uniformity data back to the mixer control unit. The mixing control unit then regulates the air volume of the air injection device and the speed of the main shaft according to the uniformity data.

[0091] What is specific is how in Fig.Figure 1 shows a uniformity detection system 21 provided on a discharge line 20 connected to a discharge opening of the mixer to detect the uniformity of the material discharged from the discharge opening. The uniformity data is transmitted to the mixer control unit 22 after detection. In the present application, the CaO content in the mixer material is monitored in real time, and the relevant information is promptly reported back to the mixer control unit 22. The mixer control unit 22 adjusts and controls the air volume in the air injection device and the rotational speed of the main shaft according to the uniformity data to ensure the uniformity of the material mixture in the mixer, so that the composition of the final product does not vary within a specific range.

[0092] As in Fig.As shown in Figure 1, the mixed material discharged from the discharge opening is transported through the discharge line 20 to the material hopper of the third bucket elevator 24, the third bucket elevator 24 lifts the material hopper and pours the material into the product storage area 23 for storage.

[0093] The present invention also provides a method for producing low-CO2 cement by staged and separate grinding, which is carried out using the system for producing low-CO2 cement by staged and separate grinding according to the present invention, wherein the method comprises the following steps: Step 1. Production of desired material components for low-CO2 cement, including: an early self-activating gelling component, a medium-term self-activating gelling component, a long-term self-activating gelling component, and a rheologically active material component. wherein the early self-activating gelling component comprises silicate cement clinker, granulated blast furnace slag and grinding aids, wherein the process for producing the early self-activating gelling component is as follows: Conveying of a metered mixture of silicate cement clinker, granulated blast furnace slag and grinding aid via the first bucket elevator 25 to the first conveying device 26 and then through the first conveying device 26 into the vertical mill for grinding 27, wherein the material obtained in the vertical mill 27 has a specific surface area of ​​400 m² 2 / kg - 500 m 2 / kg is collected under the action of the first exhaust fan 30 in the first dust separator 29 and then transported to the ball mill 31 for further grinding, Sorting of the material from the classifier 33, after the material has been ground again by the ball mill 31, the resulting material having a specific surface area of ​​1150 m² 2 / kg - 1250 m 2 / kg is collected by the second dust separator 34 under the action of the second exhaust fan 35 and then transported through the air conveying trough 36 into the first silo 16-2, wherein the medium-term self-activating gelling component comprises a silicate cement clinker and a gypsum, wherein the process for producing the medium-term self-activating gelling component is as follows: Filling a metered mixture of the silicate cement clinker and the gypsum into the first bucket elevator 25, wherein the mixture is transferred through the first bucket elevator 25 into the first conveying device 26 and then transported to the vertical mill 27 for grinding, wherein the material has a specific surface area of ​​380 m² 2 / kg up to 400 m2 / kg after grinding by the vertical mill 27 under the action of the first exhaust fan 30 is collected in the first dust separator 29 and then transferred to the second silo 16-1, wherein the long-term self-activating gelling component comprises one or more of fly ash, steel slag, furnace slag, phosphorus slag and coal grit, wherein the process for producing the long-term self-activating gelling component is as follows: Conveying a metered, long-term, self-activating, gelling component, after it has been filled into the first bucket elevator 25, through the first conveying device 26 into the vertical mill for grinding 27, wherein after grinding the material has a specific surface area of ​​400 m² 2 / kg - 450 m 2 / kg is collected from the first dust separator 29 under the suction action of the first exhaust fan 30 and then transferred to the ball mill 31 for further grinding and then transferred through the second bucket elevator 32 to the classifier 33, the material obtained from the classifier 33 having a specific surface area of ​​480 m² 2 / kg - 550 m 2 / kg is collected from the second dust separator 34 under the action of the second exhaust fan 35 and then transferred through the air conveying trough 36 into the third silo 16-3, wherein the rheologically active material component is quartz sand or limestone, wherein the process for producing the rheologically active material component is as follows: Filling of the metered rheologically active material component into the first bucket elevator 25 and subsequent conveying of the metered rheologically active material component through the first conveying device 26 to the vertical mill 27 for grinding, wherein after grinding the obtained material has a specific surface area of ​​200 m² 2 / kg up to 240 m 2 / kg is collected from the first dust separator 29 under the suction action of the first exhaust fan 30, wherein the material collected by the first dust separator 29 is transferred to the ball mill 31 for further grinding and after re-grinding in the ball mill 31 the material is then transferred via the second bucket elevator 32 to the classifier 33, wherein the material obtained from the classifier 33 has a specific surface area of ​​240m² 2 / kg - 300m 2 / kg is collected from the second dust separator 34 under the action of the second exhaust fan 35 and then transferred through the air conveying trough 36 into the fourth silo 16-4, Step 2: Transferring the material in each silo first into the appropriate buffer tank, after all material components have been produced, whereby the material is dosed with the appropriate dosing device and then transferred to the mixer for mixing, whereby after mixing the desired low-CO2 cement is obtained.

[0094] In one possible embodiment, it is provided that in the production of the early self-activating gelling component, the material obtained after milling by the vertical mill 27 has a specific surface area of ​​less than 400 m². 2 / kg is transported via the second conveying device 28 back to the first bucket elevator 25, in the production of the medium-term self-activating gelling component, the material obtained after milling by the vertical mill 27 has a specific surface area of ​​less than 380 m² 2 / kg is transported via the second conveying device 28 back to the first bucket elevator 25, wherein, in the production of the long-term self-activating gelling component, the material obtained after milling by the vertical mill 27 has a specific surface area of ​​less than 400 m² 2 / kg is transported via the second conveying device 28 back to the first bucket elevator 25, in the production of the rheologically active material component, the material obtained after grinding by the vertical mill 27 has a specific surface area of ​​less than 200 m² 2 / kg is transported again to the first bucket elevator 25 via the second conveying device 28.

[0095] In one possible embodiment, it is provided that in the production of the early self-activating gelling component, the material has a specific surface area of ​​less than 1150 m². 2 / kg after sorting by the classifier 33 is fed into the ball mill 31 for re-grinding, where, in the production of the medium-term self-activating gelling component, the material has a specific surface area of ​​less than 480m² 2 / kg after sorting by the classifier 33 is fed into the ball mill 31 for re-grinding, where, in the production of the rheologically active material component, the material has a specific surface area of ​​less than 240m² 2 / kg is fed into the ball mill 31 for re-grinding after sorting by the classifier 33.

[0096] In one possible embodiment, it is provided that during the production of the early self-activating gelling component, the material collected by the third dust separator 37 connected to the ball mill 31 enters the first silo 16-2 directly under the action of the third exhaust fan 38, wherein during the production of the long-term self-activating gelling component, the material collected by the third dust separator 37, connected to the ball mill 31, enters the third silo 16-3 directly under the action of the third exhaust fan 38, during the production of the rheologically active material component, the material collected by the third dust separator 37, connected to the ball mill 31, passes directly into the fourth silo 16-4 under the action of the third exhaust fan 38.

[0097] Specifically, the low-CO2 cement produced in the present application is a self-stimulated low-CO2 cement comprising the following raw materials by weight: the early self-activating gelling component is 15 to 20 parts, the medium-term self-activating gelling component is 45 to 50 parts, the long-term self-activating gelling component is 20 to 25 parts, and the rheologically active material component is 10 to 15 parts.

[0098] The self-activating gelling material in the early stage comprises silicate cement clinker, granulated blast furnace slag and grinding aids in a mass ratio of 1:3:0.002, the particle size range is 0.1 to 10 µm, the specific particle surface area is 1150 to 1250 m² 2 / kg and the uniformity coefficient is greater than 1.1.

[0099] The grinding aid is industrial-grade diethanolmonoisopropanolamine or diisopropylethylamine and its active ingredient content is ≥ 85%.

[0100] The self-activating gelling material in the intermediate stage comprises silicate cement clinker and gypsum with a mass ratio of 95:5 and a specific particle surface area of ​​380 to 400 m². 2 / kg, a uniformity coefficient of over 1.1 and a sieve residue of R 45 µm of less than 5%.

[0101] The self-activating gelling material in the long stage consists of one or more of fly ash, steel slag, furnace slag, phosphorus slag and coal grit and has a specific particle surface area of ​​480 to 550 m². 2 / kg, a uniformity coefficient of over 1.1 and a sieve residue of R 45µm of less than 2%.

[0102] The rheologically active material consists of quartz sand and limestone and has a specific particle surface area of ​​240 to 300 m². 2 / kg, a uniformity coefficient of over 0.9 and a sieve residue of R 45pm from under 40%.

[0103] The 3-day activity index for self-activating gelling material in the early stage is ≥100%, the 28-day activity index for self-activating gelling material in the long stage is 65% to 80%, and there are no activity requirements for rheologically active material.

[0104] The process for producing low-CO2 cement with gradient self-excitation using a system with staged and separate grinding proceeds as follows: Production of the early self-activating gelling component: Silicate cement clinker, granulated blast furnace slag, and grinding aids are dosed in a specific ratio from the feed opening 39 into the first bucket elevator 25 and then conveyed via the first conveying device 26 into the vertical mill 27 for grinding. Under the negative pressure of the first exhaust fan 30, 400 to 500 m³ are extracted after grinding. 2 / kg of fine powder is obtained and drawn into the first dust separator 29 for collection; the gas cleaned by the first dust separator 29 is discharged from the first exhaust fan 30. After grinding in the vertical mill 27, the material has a specific particle surface area of ​​less than 400 m². 2 / kg via the second conveying device 28 together with silicate cement clinker, granulated blast furnace slag and grinding aids, which are metered, fed to the first bucket elevator 25 for the second grinding, the grinding is repeated until the specific surface area of ​​the powder is 400 to 500 m² 2 / kg is reached and is collected by the first dust separator 29.

[0105] The fine powder collected by the first dust separator 29 has a diameter of 400 to 500 m³ 2 The material (kg) is transported to the ball mill 31 for re-milling. The material milled by the ball mill 31 is discharged from the milling head into the second bucket elevator 32 and then proceeds to the classifier 33 for sorting. After sorting by the classifier 33, the material has a specific particle surface area of ​​1150 to 1250 m². 2 The material is collected by the second dust separator 34 under the negative pressure of the second exhaust fan 35. The material collected by the second dust separator 34 passes through the air conveying trough 36 into the first silo 16-2. The material has a specific particle surface area of ​​less than 1150 m². 2 After sorting by the classifier 33, the material (kg) is returned to the ball mill 31 to be ground again until the specific particle surface area reaches 1150 to 1250 m². 2 / kg is reached, and then collected by the second dust separator 34. The ventilation in the mill of the ball mill 31 is cleaned by the third dust separator 37, the fine powder collected by the third dust separator 37 goes directly into the first product storage, the gas cleaned by the third dust separator 37 is released by the third exhaust fan.

[0106] Furthermore, prior to the production of the early self-activating gelling component for the granulated blast furnace slag, a mineral powder is used in the raw material of the early self-activating gelling material, which is ground to a specific fineness, and the specific surface area of ​​the mineral powder is 400 to 450 m². 2 / kg, for grinding the mineral powder, the final grinding system of a ball mill can be used. The mineral powder with a specific fineness, silicate cement clinker ground in a vertical mill 27, and grinding aids are dosed in a specific ratio and then enter the ball mill 31 to be ground again. The material ground by the ball mill 31 enters the classifier 33 for sorting to remove an early self-activating gelling component with a specific particle surface area of ​​1150 to 1250 m². 2 / kg. The material with a specific particle surface area of ​​less than 1150 m². 2 / kg after sorting by the classifier 33 is returned to the ball mill 31 for re-grinding.

[0107] Production of the medium-term self-activating gelling component: The metered silicate cement clinker and gypsum are filled from the feed opening 39 into the first bucket elevator 25 after metering and then pass via the first conveying device 26 into the vertical mill 27 for grinding. The material is ground in the vertical mill 27. After grinding, the fine powder has a specific surface area of ​​380 to 400 m². 2 The gas, collected in the first dust separator 29, is discharged from the first exhaust fan 30. After grinding in the vertical mill 27, the material has a specific particle surface area of ​​less than 380 m². 2 / kg is conveyed through the second conveying device 28 and, together with the metered silicate cement clinker and gypsum, enters the first bucket elevator 25 for second grinding; the grinding is repeated until the specific surface area of ​​the particle is 380 to 400m² 2 / kg is reached and collected by the first dust separator 29, the material collected by the first dust separator 29 is sent to the second product storage. Production of the long-term self-activating gelling component: A metered mixture of one or more materials, including fly ash, steel slag, furnace slag, phosphorus slag, and coal grit, is metered and introduced via the feed opening 39 into the first bucket elevator 25 and then transported via the first conveying device 26 to the vertical mill 27 for grinding. After grinding, the fine powder has a specific surface area of ​​400 to 450 m². 2 / kg is collected in the first dust separator 29 under the negative pressure of the first exhaust fan 30; the gas cleaned by the first dust separator 29 is discharged from the first exhaust fan 30. The material has a specific particle surface area of ​​less than 400 m². 2 / kg after grinding with the vertical mill 27 is conveyed by the second conveying device 28 together with a metered mixture of one or more materials, including fly ash, steel slag, furnace slag, phosphorus slag and coal grit, to the first bucket elevator 25 for a second grinding; the grinding is repeated until the specific surface area of ​​the particles reaches 400 to 450 m². 2 / kg achieved.

[0108] The fine powder in the first dust separator 29 has a specific particle surface area of ​​400 to 450 m² 2 The material (kg) is transferred to the ball mill 31 for further grinding. The material ground by the ball mill 31 is discharged from the grinding head and transferred to the classifier 33 for sorting. The material sorted by classifier 33 has a specific surface area of ​​480 to 550 m². 2The material (kg) is collected by the second dust separator 34 under the negative pressure of the second exhaust fan 35. The material collected by the second dust separator 34 is conveyed via the air conveyor trough 36 into the third silo 16-3. After sorting by the classifier 33, the material with a specific surface area of ​​less than 480 m² 2 / kg returned to ball mill 31 to be ground again until the specific surface area of ​​the material is 480 to 550 m² 2 / kg is achieved. The ventilation in the mill of the ball mill 31 is cleaned by the third dust separator 37, the fine powder collected by the third dust separator 37 goes directly into the third silo 16-3, the gas cleaned by the third dust separator 37 is released by the third exhaust fan 38.

[0109] If the raw material for the long-stage product is powder, the final grinding system of the ball mill can also be used directly, and the metered material is ground again by the ball mill 31 to a specific fineness. After the material has been ground in the ball mill 31, it is transferred to the classifier 33 for sorting to produce a final product of self-activating gelling material in the long stage with a specific surface area of ​​480 to 550 m². 2 / kg to obtain, the unsuitable material after sorting by the classifier is returned to the ball mill to be ground again until the specific surface area of ​​the material is 480 to 550 m². 2 / kg achieved.

[0110] Production of the material components of the rheologically active material: After dosing, either the quartz sand or the limestone is filled into the first bucket elevator 25 via the feed opening 39 and then passes through the first bucket elevator 25 into the vertical mill 27 for grinding. The fine powder obtained after grinding in the vertical mill 27 has a specific surface area of ​​200 to 240 m². 2 The material (kg) is collected under the negative pressure of the first exhaust fan 30 in the first dust separator 29. The gas cleaned by the first dust separator 29 is discharged from the first exhaust fan 30. After grinding in the vertical mill 27, the material has a specific surface area of ​​less than 200 m². 2 / kg is transported via the second conveying device 28 to the bucket elevator and, together with quartz sand or limestone from the feed opening 39, is directed into the first bucket elevator 25 for the second grinding, until the material is collected by the first dust separator 29, after which its specific surface area is 200 to 240 m². 2 / kg achieved. The material collected in the first dust separator 29 has a specific surface area of ​​200 to 240 m² 2 The material (kg) is transferred to the ball mill 31 for further grinding. The material ground by the ball mill 31 is discharged from the grinding head and passes via the second bucket elevator 32 to the classifier 33 for sorting. The classifier 33 sorts the material with a specific surface area of ​​240 to 300 m². 2 / kg, which is collected by the second dust separator 34 under the negative pressure of the second exhaust fan 35 and then sent through the air conveying trough 36 to the fourth silo 16-4. After sorting by the classifier 33, the material with a specific surface area of ​​less than 240 m² 2 / kg returned to ball mill 31 to be ground again until the specific surface area is 240 to 300 m² 2 / kg is reached, and then collected by the second dust separator 34. The ventilation in the mill of the ball mill 31 is cleaned by the third dust separator 37, the material collected by the third dust separator 37 is conveyed via the air conveying trough 36 directly into the fourth silo 16-4. The gas cleaned by the third dust separator 37 is released by the third exhaust fan 38.

[0111] The corresponding early self-activating gelling component, medium-term self-activating gelling component, long-term self-activating gelling component and rheologically active material component from respective silos are each fed into the corresponding buffer container 18, dosed to a preset weight by the respective metering devices 17 and transferred by the feed device 2 into the mixing chamber 1 for mixing and homogenization, and then discharged from the discharge opening 3 to finally produce low-CO2 cement with gradient self-excitation.

[0112] It should be noted that the rheologically active material, based on grinding in a vertical mill, uses a ball mill grinding system to further shape the particle size of the material by grinding in order to achieve better sphericity and further improve the fineness.

[0113] The present invention proposes a novel concept for the development and production of low-CO2 cement, consisting of the stepwise production of self-activating gelling material in the early, mid, and long stages by regulating particle size and gelling activity, and the construction of a gradient self-excitation system for low-CO2 cement through adaptation and optimization of the design. During the hydration process, this type of low-CO2 cement initially relies on the vigorous hydration reaction of the self-activating gelling material in the early stage to rapidly establish early strength, thus compensating for the slow early strength development of the low-CO2 cement due to its low clinker content.Simultaneously, a large number of tetrahedral silicon / aluminum units are released, increasing the early ion activity and supersaturation of the pore solution, promoting nucleation and growth of hydration products, stimulating the mid-stage hydration reaction of the self-activating gelling material, and accelerating the medium-term strength development of low-CO2 cement. This process is carried out continuously, further increasing the alkalinity of the pore solution in the late hydration phase, promoting the depolymerization of the inert aluminosilicate tetrahedron of the self-activating gelling material in the long stage, and synergistically stimulating the long-stage reaction of the self-activating gelling material. This strengthens the matrix of the low-CO2 cement, achieves stable long-term strength growth, and improves the durability of cement-based materials.

[0114] By installing a combined milling system consisting of a vertical mill and a ball mill, different types of materials can be processed according to their particle size distribution. This allows for the selection of final milling in the vertical mill, ring flow milling in the ball mill, or a combined process using both methods, thus fully utilizing the properties of each milling process. Under conditions of minimal energy consumption and maximum production yield, a self-activating gelling material with varying degrees of fineness and particle size distribution is obtained. After mixing in a mixer, low-CO2 cement with an ideal particle size distribution is produced, improving the cement's performance.

[0115] The present invention also has the following advantages and technical effects: (1) In contrast to cement produced by conventional methods, the low-CO2 gradient self-excitation cement produced by the present invention can exhibit the mechanical advantages of rapid strength development in the early and middle phases and stable strength development in the long-term phase, based on a significantly reduced amount of clinker and reduced total CO2 emissions. (2) By introducing the grinding aid, the grinding performance of the self-activating gelling material can be significantly improved in the early stage and energy consumption in production can be reduced, and the strong ion complexation effect of the organic grinding aid can be used to fully stimulate the activity of the self-activating gelling material in the early stage and promote the early strength development of low-CO2 cement. (3) By introducing the rheologically active material, the particle size distribution of low-CO2 cement can be expanded, the particle size distribution optimized, the water requirement of low-CO2 cement reduced and the workability improved.

[0116] In the present invention, several sections of the agitator are provided with opposite directions of rotation. This not only achieves relative disturbance of the mixture in opposite directions, but also extends the residence time of the mixture in this area, improves the mixing performance, and reduces inefficient energy consumption. By setting a different number of conical teeth on the differential-speed agitator on the main shaft, gradient stirring is performed along the mixing axis during the mixing process. This improves mixing efficiency and uniformity while simultaneously reducing energy consumption, increasing production efficiency, and facilitating the use of large equipment.By installing a buffer tank and a dosing device upstream of the conveying system, unstable feeding can be prevented, feeding stability effectively controlled, and dosing accuracy improved. By implementing a system with a vertical mill and a ball mill, the various components of the low-CO2 cement can be milled separately according to their properties, ensuring that each component achieves the optimal degree of milling. After mixing in a mixer, the resulting low-CO2 cement has an ideal particle size distribution, thus improving the cement's performance. The present invention is explained in more detail with reference to the following exemplary embodiments:

[0117] The system and method for producing low-CO2 cement by staged and separate grinding according to the present invention are used to produce the self-activating gelling material in the early, middle and long stages as well as rheologically active material, which, after mixing in specific proportions, are measured for the properties of cements of different configurations; the test results are shown in Tables 1 to 4: Table 1: First test for the low-CO2 cement with gradient self-excitation with classified particle size registration Portion, % Specific surface area, m 2 / kg uniformity coefficient 3-day compressive strength, MPa 28-day compressive strength, MPa Self-activating gelling material in the early stage 15 1150 0.83 32.6 59.8 Self-activating gelling material in the mid-stage 50 380 Self-activating gelling material in the long stage 20 480 Rheologically active material 15 240 Table 2: Second test for the low-CO2 cement with gradient self-excitation with classified particle size registration Portion, % Specific surface area, m 2 / kg uniformity coefficient 3-day compressive strength, MPa 28-day compressive strength, MPa Self-activating gelling material in the early stage 20 1250 0.87 34.2 62.5 Self-activating gelling material in the mid-stage 45 380 Self-activating gelling material in the long stage 25 550 Rheologically active material 10 240 Table 3: Third test for the low-CO2 cement with gradient self-excitation and classified particle size registration Portion, % Specific surface area, m 2 / kg uniformity coefficient 3-day compressive strength, MPa 28-day compressive strength, MPa Self-activating gelling material in the early stage 15 1150 0.84 33.5 61.4 Self-activating gelling material in the mid-stage 50 400 Self-activating gelling material in the long stage 25 550 Rheologically active material 10 240 Table 4: Fourth test for the low-CO2 cement with gradient self-excitation with classified particle size registration Portion, % Specific surface area, m 2 / kg uniformity coefficient 3-day compressive strength, MPa 28-day compressive strength, MPa Self-activating gelling material in the early stage 20 1150 0.85 33.8 62.1 Self-activating gelling material in the mid-stage 48 380 Self-activating gelling material in the long stage 22 480 Rheologically active material 10 300

[0118] According to the performance requirements for ordinary silicate cement PO. 42.5 in GB1752007 "General silicate cement", the 3-day compressive strength is 17 MPa and the 28-day compressive strength is 42.5 MPa, as shown in Tables 1 to 4 above. The system and method for producing low-CO2 cement by staged and separate grinding in the present invention are used to produce self-activating gelling material as well as early-stage, mid-stage, and long-stage rheologically active material, which, after mixing in specific proportions, exhibit the measured 3-day and 28-day compressive strengths, both of which are better than those specified in the performance requirements for ordinary silicate cement PO. 42.5 in GB1752007 “General silicate cement” are, at the same time the uniformity coefficient is below 0.9, the particle distribution is wider, the water requirement of the cement is reduced and the performance of the cement is improved.

[0119] Although the preferred embodiments of the present invention have been described, those skilled in the art in this field are able to make additional changes and modifications to these embodiments once they understand the basic inventive concept. Therefore, it is intended that the appended claims be interpreted to encompass the preferred embodiments and all changes and modifications that fall within the scope of the invention.

[0120] Obviously, a person skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the invention. If these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies, then the present invention is also intended to encompass these modifications and variations. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] GB 1752007

[0118]

Claims

System for the production of low-CO2 cement by staged and separate grinding, characterized in that the system comprises a grinding system and a mixing system, wherein the grinding system comprises a first bucket elevator, a first conveying device, a vertical mill, a first dust separator and a first exhaust fan connected in series, wherein the first conveying device is used to convey material from the first bucket elevator to the vertical mill, wherein the grinding system also comprises a first dust separator, a ball mill, a second bucket elevator, a classifier, a second dust separator and an air conveying trough connected in series, wherein the second dust separator is also connected to a second exhaust fan, wherein the vertical mill is also connected to a second conveying device used to convey material to the first bucket elevator.wherein the ball mill is also connected to a third dust separator, which is connected to a third exhaust fan, wherein the third dust separator is also connected to the air conveying trough, wherein the air conveying trough is each connected to a first silo, a third silo and a fourth silo, wherein the first dust separator is also connected to a second silo, wherein the first silo, the second silo, the third silo and the fourth silo are used for storing different goods, wherein the mixing system comprises a mixer, several buffer tanks and several metering devices, wherein each of the buffer tanks is connected to a metering device accordingly, wherein the mixer comprises a housing, a feed device and a discharge opening, wherein the first silo, the second silo, the third silo and the fourth silo are each connected to a corresponding buffer tank,wherein the housing is inclined upwards from the discharge opening side to the feed device side at an angle of 2° to 10°, wherein the feed device is arranged in the upper region of the first end of the housing, wherein the discharge opening is arranged on the side surface of the second end of the housing, wherein the metering device is connected to the feed device via a feed line, and the material from each silo is transferred from the respective metering device via the feed line into the mixer for stirring and mixing, wherein a first agitator is arranged in the housing parallel to the housing, wherein the first agitator comprises a main shaft which is driven by a main shaft drive device, and wherein the main shaft is provided with several agitators which are mounted continuously along the axial direction of the main shaft, each of the agitators comprising two gear bevel gears and a main shaft bevel gear.which runs coaxially to the main shaft, comprises two spur gears, two large rim gears and two hollow shafts, wherein the two bevel gears are arranged symmetrically on both sides of the main shaft and simultaneously mesh with the main shaft bevel gears mounted and fastened on the main shaft, wherein the two spur gears are each arranged on the outside of their respective bevel gears and are each connected to the two bevel gears via a gear shaft, wherein the two large rim gears are supported by a rim gear support cylinder, wherein the two spur gears are located between the two large rim gears and each of the spur gears is meshed with the two large rim gears.wherein the axial direction of the gear ring support cylinder is parallel to the main shaft and both ends of the gear ring support cylinder are each attached to the side surface of the first and second ends of the mixer, wherein each of the hollow shafts is firmly connected to a large gear ring and the two hollow shafts are closely fitted to each other at a coupling position to prevent the material from being transferred into the agitator, wherein each of the hollow shafts is provided with several first vanes, wherein the two hollow shafts rotate in opposite directions under the rotation of the main shaft to stir and mix the material in the housing, wherein the number of teeth of the respective main shaft bevel gear of each agitator on the main shaft is different, so that the first agitator stirs the material at different speeds at different positions in the housing. System for the production of low-CO2 cement by staged and separate grinding according to claim 1, characterized in that the system further comprises a hot air oven which supplies the entire system with hot air. System for producing low-CO2 cement by staged and separate grinding according to claim 1, characterized in that the first wing has a uniform overall cutting thickness, wherein the first wing has a wave-like structure and is used to move the material in several directions at variable speed. System for the production of low-CO2 cement by staged and separate grinding according to claim 3, characterized in that the first wing comprises a root and a tip, wherein the tip is located at the upper end of the first wing, wherein the root is connected to the outer surface of the hollow shaft, and wherein the tip is directed towards the discharge opening. System for the production of low-CO2 cement by staged and separate grinding according to claim 1, characterized in that the bottom and sides of the housing are also provided with air injection devices to adjust the trajectory and residence time of the materials in the housing. System for the production of low-CO2 cement by staged and separate grinding according to claim 5, characterized in that the air injection devices are connected to an air mixing chamber which is connected to an air supply fan, wherein the air supply fan is used to supply the air mixing chamber with air pressure, wherein the air mixing chamber is used to supply the air injection devices with air pressure, wherein the air injection device comprises several air inlet pipes, wherein an air inlet pipe comprises an air inlet pipe shell, a dust sealing ring, a dust deflector plate and a flap valve, wherein the air outlet port of the air inlet pipe faces the interior of the housing, wherein the inner surface of the top of the air outlet port is provided with a dust sealing ring and several dust deflector plates which are located in the center of the dust sealing ring and are connected with the same pivot axis.wherein the dust deflectors are semicircular and their diameter corresponds to the inner diameter of the dust sealing ring, wherein the dust deflectors are turned up and down under the influence of air pressure, wherein the air inlet port of the air inlet pipe is connected to the air mixing chamber and a flap valve is provided at a port to which the air inlet port is connected to the air mixing chamber, wherein the flap valve is connected to the flap valve control, wherein the flap valve control controls the amount of air entering the air inlet pipe by controlling the pivot dimension of the flap valve. System for the production of low-CO2 cement by staged and separate grinding according to claim 1, characterized in that the feeding device comprises an inlet opening and an air barrier structure mounted in the inlet opening, wherein the air barrier structure comprises an air barrier housing, an air barrier drive device, an air barrier rotating shaft and an air barrier blade, wherein the air barrier rotating shaft is fixed horizontally in the inlet opening and is driven to rotate by the air barrier drive device, wherein several air barrier blades are mounted on the axial circumference of the air barrier rotating shaft, wherein an end face of the air barrier blade is connected to the air barrier rotating shaft and the other end faces each bear against the air barrier housing, wherein during feeding the air barrier rotating shaft drives the air barrier blades so that the air barrier blades rotate and convey the material into the housing, or wherein the feeding device comprises a screw feeder.wherein the screw feeder comprises a screw feeder housing, wherein the inlet opening of the screw feeder is inclinedly attached to the screw feeder housing and communicates with the screw feeder housing, wherein the bottom of the screw feeder housing communicates with the interior of the housing, wherein a screw spindle and spirally distributed screw vanes attached to the screw spindle are arranged vertically in the screw feeder housing, wherein a grid plate is attached to the bottom of the screw spindle, the grid plate comprising several L-shaped grid bars, the L-shaped grid bars comprising vertical sides and inclined sides, the vertical sides being located above the inclined sides, one end of the inclined sides being connected to the screw spindle and the other end being connected to a lower end of the vertical sides. System for the production of low-CO2 cement by staged and separate grinding according to claim 1, characterized in that four first agitators are present in the housing and the four first agitators are divided into an upper level and a lower level, wherein two agitators are arranged on each level. System for producing low-CO2 cement by staged and separate grinding according to claim 8, characterized in that several groups of barrier units are distributed along the main shaft in the housing, wherein the barrier units divide the interior of the housing into several mixing chambers, wherein a barrier unit comprises an upper barrier structure and a lower barrier structure arranged one above the other, wherein the upper barrier structure and the lower barrier structure are located on the same vertical plane, wherein each barrier structure comprises a lower fixed barrier plate and an upper movable barrier plate with which the quantity of material in the mixing chamber is controlled that is transferred to an adjacent mixing chamber. System for the production of CO2-low cement by staged and separate grinding according to claim 9, characterized in that a guide plate is arranged on the top of each mixing chamber, wherein the vertical height of the guide plate is complementary to the vertical distance from the top of the corresponding barrier unit to the ceiling surface in the housing, wherein the guide plate is used to further control the residence time of the material in the mixing chamber. System for the production of low-CO2 cement by staged and separate grinding according to claim 9, characterized in that at least one vertical agitator is provided on the top of each mixing chamber, wherein the rotational speed of the vertical agitator can be adjusted according to the mixing conditions in the mixing chamber. A process for producing low-CO2 cement by staged and separate grinding, characterized in that the process is carried out based on the system for producing low-CO2 cement by staged and separate grinding according to any one of claims 1 to 11 and comprises the following steps: Step 1: Production of desired material components for low-CO2 cement, comprising: an early self-activating gelling component, a medium-term self-activating gelling component, a long-term self-activating gelling component, and a rheologically active material component, wherein the early self-activating gelling component comprises silicate cement clinker, granulated blast furnace slag, and grinding aids, wherein the process for producing the early self-activating gelling component is as follows: Conveying a metered mixture of silicate cement clinker,Granulated blast furnace slag and grinding aids are conveyed via the first bucket elevator to the first conveying device and then through the first conveying device into the vertical mill for grinding, wherein the material obtained in the vertical mill, with a specific surface area of ​​400 m² / kg - 500 m² / kg, is collected in the first dust separator under the action of the first exhaust fan and subsequently transported to the ball mill for further grinding; sorting of the material by the classifier after it has been ground again by the ball mill, wherein the material obtained, with a specific surface area of ​​1150 m² / kg - 1250 m² / kg, is collected by the second dust separator under the action of the second exhaust fan and then transported through the air conveying trough into the second silo; wherein the medium-term self-activating gelling component comprises a silicate cement clinker and a gypsum.wherein the process for producing the medium-term self-activating gelling component proceeds as follows: filling a metered mixture of the silicate cement clinker and the gypsum into the first bucket elevator, wherein the mixture is transferred by the first bucket elevator into the first conveying device and then transported to the vertical mill for grinding, wherein the material with a specific surface area of ​​380 m² / kg to 400 m² / kg is collected after grinding by the vertical mill under the action of the first exhaust fan in the first dust collector and then transferred to the first silo, wherein the long-term self-activating gelling component comprises one or more of fly ash, steel slag, furnace slag, phosphorus slag and coal grit, wherein the process for producing the long-term self-activating gelling component proceeds as follows: conveying a metered long-term self-activating gelling component,After being filled into the first bucket elevator, the material is conveyed by the first conveyor into the vertical mill for grinding. After grinding, the material, with a specific surface area of ​​400 m² / kg - 450 m² / kg, is collected by the first dust separator under the suction action of the first exhaust fan and then transferred to the ball mill for further grinding. It is then transferred by the second bucket elevator to the classifier. The material obtained from the classifier, with a specific surface area of ​​480 m² / kg - 550 m² / kg, is collected by the second dust separator under the action of the second exhaust fan and then transferred by the air conveying trough to the third silo. The rheologically active material component is quartz sand or limestone.The process for producing the rheologically active material component proceeds as follows: The metered rheologically active material component is filled into the first bucket elevator and then conveyed by the first conveying device to the vertical mill for grinding, whereby after grinding the resulting material with a specific surface area of ​​200 m² / kg to 240 m² / kg is collected by the first dust separator under the suction action of the first exhaust fan, whereby the material collected by the first dust separator is transferred to the ball mill for further grinding and after further grinding in the ball mill the material is then transferred via the second bucket elevator to the classifier.The material obtained from the classifier, with a specific surface area of ​​240 m² / kg - 300 m² / kg, is collected by the second dust separator under the action of the second exhaust fan and then transferred via the air conveying trough to the fourth silo. Step 2: Transfer of the material in each silo first to the corresponding buffer tank after all material components have been produced, the material being metered with the corresponding metering device and then transferred to the mixer for mixing, whereby the desired low-CO2 cement is obtained after mixing. A method for producing low-CO2 cement by staged and separate milling according to claim 12, characterized in that, in the production of the early self-activating gelling component, the material obtained after milling by the vertical mill with a specific surface area of ​​less than 400 m² / kg is transported again to the first bucket elevator via the second conveying device; in the production of the medium-term self-activating gelling component, the material obtained after milling by the vertical mill with a specific surface area of ​​less than 380 m² / kg is transported again to the first bucket elevator via the second conveying device; in the production of the long-term self-activating gelling component, the material obtained after milling by the vertical mill with a specific surface area of ​​less than 400 m² / kg is transported again to the first bucket elevator via the second conveying device.and in the production of the rheologically active material component, the material obtained after grinding by the vertical mill, with a specific surface area of ​​less than 200 m² / kg, is transported again to the first bucket elevator via the second conveying device. A method for producing low-CO2 cement by staged and separate grinding according to claim 12, characterized in that, in the production of the early self-activating gelling component, the material with a specific surface area of ​​less than 1150 m2 / kg is fed into the ball mill for re-grinding after sorting by the classifier, in the production of the long-term self-activating gelling component, the material with a specific surface area of ​​less than 480 m2 / kg is fed into the ball mill for re-grinding after sorting by the classifier, and in the production of the rheologically active material component, the material with a specific surface area of ​​less than 240 m2 / kg is fed into the ball mill for re-grinding after sorting by the classifier. A method for producing low-CO2 cement by staged and separate grinding according to claim 12, characterized in that, in the production of the early self-activating gelling component, the material collected by the third dust separator connected to the ball mill is transported directly into the first silo by the third exhaust fan, in the production of the long-term self-activating gelling component, the material collected by the third dust separator connected to the ball mill is transported directly into the third silo by the third exhaust fan, and in the production of the rheologically active material component, the material collected by the third dust separator connected to the ball mill is transported directly into the fourth silo by the third exhaust fan.

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