Preparation system and method of high-belite low-heat Portland cement

Abstract

The invention discloses a high belite ultra-low heat Portland cement preparation system which comprises a batching warehouse and a gypsum warehouse, the batching warehouse and the gypsum warehouse are connected with a mixing feeding bin through a first conveying module, a roller press is installed at the discharging end of the mixing feeding bin, and the discharging end of the roller press is connected with a multi-stage grading module through an elevator; the fine powder discharging end of the multi-stage grading module is connected to the interiors of all bins of the grading bin, coarse materials at the tail of the multi-stage grading module flow back to the mixing feeding bin, and the invention further discloses a preparation method of the high-belite ultra-low-heat Portland cement. The production system and method are improved, in the grinding process, multiple times of graded mixing are carried out, granularity distribution is easy to control, the grinding difficulty is reduced, the yield of products can be improved, production energy consumption can be further reduced, products with different particle size distribution can be produced according to arrangement of the system, and the production efficiency is improved. And therefore, different material requirements are met.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of cement production, in particular to a preparation system and method of high-belite low-heat portland cement. BACKGROUND

[0002] High-belite cement is mainly high-belite cement taking belite minerals (C2S) as the main component, and the content is about 50%, so that the high-belite cement and concrete have a series of excellent performance characteristics such as low hydration heat, high final strength and good durability. It sacrifices part of the early strength, and in return, it has the valuable characteristics of low hydration heat, high late strength and excellent durability. It is a key material for solving the temperature crack problem of mass concrete and building long-life high-performance engineering.

[0003] The core of the cement in the application process is that after the cement is added with water, the main minerals (C3S, C2S, C3A and C4AF) in the cement will have a hydration reaction to generate hydration calcium silicate (C-S-H) gel and other products. C-S-H gel is the main source of cement stone strength. In specific construction, the larger the specific surface area, the larger the contact area with water, the faster the hydration reaction speed, and the early strength develops rapidly, which can make up for the lack of early strength, but it will cause an increase in water demand. The specific surface area of fine particles is large, and more water is needed to wet and maintain the same construction fluidity. High water demand will lead to an increase in cement stone porosity, which is not conducive to the late strength. The coarser the particle size, the smaller the specific surface area, and the slower the hydration reaction, but the late hydration can continue to provide long-term strength. Therefore, the ideal cement particle distribution is not the finer the better, nor the coarser the better, but a reasonable gradation is needed. In the preparation process, different allocations need to be arranged according to specific scenarios. At present, the production line is designed according to the batch production line, and the output is large and the product is stable, but it is difficult to produce according to actual demand. In the grinding process, the particle size distribution is not uniform, and the grinding time needs to be improved, which leads to an increase in energy consumption. Therefore, the production line can produce differentiated products to meet the output, and can meet the diversified demand. For this reason, the application provides a preparation system and method of high-belite low-heat portland cement. SUMMARY

[0004] The application provides a preparation system and method of high-belite low-heat portland cement, which solves the problem that in cement production, raw materials are directly produced without grading, so that the cement particle size is not easy to configure according to demand.

[0005] The application provides a preparation system of high-berlet low-heat portland cement, which comprises a batching bin and a gypsum bin, the batching bin and the gypsum bin are connected with a mixed feeding bin through a first conveying module, a roller press is installed at the discharging end of the mixed feeding bin, the discharging end of the roller press is connected with a multi-stage grading module through an elevator, the fine powder discharging end of the multi-stage grading module is connected in each bin of a grading bin respectively, the tail coarse material of the multi-stage grading module is returned to the mixed feeding bin, the grading bin is connected with a plurality of ball mills through a batching module after batching, and the semi-finished material of the ball mill is sorted into a mixing bin after being scattered by a scattering and grading machine, a plurality of mixing bins are connected with a mixer in common, and the mixer is connected with a plurality of finished product storage bins Preferably, a fly ash bin is further arranged, and the fly ash bin is directly connected with the ball mill.

[0006] Preferably, the semi-finished material of the ball mill is sent into the scattering and grading machine through a third conveying module.

[0007] Preferably, a return pipe is further arranged between the coarse material end of the scattering and grading machine and the ball mill.

[0008] Preferably, the collecting bin of the scattering and grading machine is sent into the mixing bin through a fourth conveying module.

[0009] Preferably, the mixer is a spiral mixer.

[0010] Preferably, the spiral mixer is fed through a buffer hopper, and the mixing bin is discharged through a feeding hopper.

[0011] Preferably, the multi-stage grading module is divided into four-stage discharging.

[0012] Preferably, the particle sizes of the four-stage discharging are 0-30, 30-120, 120-300 and 300-450.

[0013] The application further discloses a preparation method of high-berlet low-heat portland cement. S1, cement raw materials are configured in a batching bin according to a set proportion, and are sent into a mixed feeding bin through a conveying module and are rolled by a roller press; S2, the rolled material is sent into a multi-stage grading module, and raw materials are graded and stored according to a set particle size value; S3, each stage of raw materials is configured according to a set proportion and is sent into a ball mill; S4, the raw materials after ball milling are graded again to obtain semi-finished materials and tail materials, the semi-finished materials are stored, and the tail materials are returned to the ball mill; S5, the semi-finished materials in each ball mill are mixed again according to a set proportion to obtain finished materials, and the finished materials are stored respectively.

[0014] From the above technical solutions, the application provides a preparation system and method of high belite low heat portland cement, the application can randomly adjust the product performance without affecting the production capacity through the hierarchical configuration on the cement production line, specifically, the ingredients are prepared through the conventional ingredient preparation bin in the ingredient preparation stage, then sent to the mixing feeding bin, the raw materials are rolled by the roller press, then the first classification is performed according to the particle size through the multi-stage classification module, the application performs four-stage classification, then the four-stage ingredients are matched according to the set proportion, then sent to different ball mills for ball milling, the screened qualified material after ball milling is stored, then mixed again according to the particle size and granularity, in fact, the particle size distribution of the mixed finished product meets the design requirements, thereby meeting the diversified production requirements.

[0015] Compared with the prior art, the application has the following beneficial effects: 1、The application can stably control the particle size of the finished product to meet the production requirements through twice dispensing, thereby ensuring the qualified rate of the product and reducing the production capacity decline and energy waste caused by the screening of unqualified products; 2、The application can complete the control of the entire system by using only one factor, and all adjustment controls are performed around the single factor, so that the quick arrangement and deployment of work adjustment is facilitated; 3、The application can facilitate the adjustment of the particle size distribution of the material, in fact, the particle size distribution of the material can be diversified according to the requirements, and the problems of increased energy consumption and reduced production caused by excessive grinding of the finished product due to unqualified particle size can be reduced.

[0016] In summary, the application improves the production system and method, performs multiple classification and mixing in the grinding process, the particle size distribution is easy to control, the grinding difficulty is reduced, the product yield can be improved, the production energy consumption can be further reduced, and different particle size distribution products can be produced according to the system settings to meet different material requirements. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the application, the drawings needed in the implementation examples will be briefly introduced as follows, and obviously, other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1 A roller press structure schematic diagram of a high belite low heat portland cement preparation system according to the application; Figure 2 A ball mill structure schematic diagram of a high belite low heat portland cement preparation system according to the application; Figure 3 A secondary mixing structure diagram of a preparation system of a high belite low heat Portland cement according to the present application; Figure 4 A fly ash warehouse feeding structure diagram of a preparation system of a high belite low heat Portland cement according to the present application; Figure 5 A particle size distribution diagram of a finished product material of a preparation system of a high belite low heat Portland cement according to the present application, with the proportion of 3-32 mu m increased; Figure 6 A particle size distribution diagram of a finished product material of a preparation system of a high belite low heat Portland cement according to the present application, under balanced conditions; Figure 7 A particle size distribution diagram of a finished product material of a preparation system of a high belite low heat Portland cement according to the present application, with the proportion of 32-115 mu m increased; Figure 8 A cement strength table of a preparation method of a high belite low heat Portland cement according to the present application.

[0019] In the figure: 1, ingredient warehouse; 2, gypsum warehouse; 3, first conveying module; 4, mixed feeding bin; 5, roller press; 6, elevator; 7, multi-stage grading module; 8, grading bin; 9, ingredient module; 10, second conveying module; 11, ball mill; 12, return pipe; 13, third conveying module; 14, dispersing and grading machine; 15, collecting bin; 16, fourth conveying module; 17, to-be-mixed material bin; 18, feeding hopper; 19, spiral mixing machine; 20, buffer hopper; 21, finished product storage; 22, fly ash warehouse. DETAILED DESCRIPTION

[0020] In order to enable personnel in the technical field to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings.

[0021] Reference should be made to Figures 1-4A preparation system of high belite low heat Portland cement, one of the core goals of modern cement grinding technology such as closed circuit ball mill system, roller press, vertical mill and the like is to accurately control the particle distribution of cement. Pursuing high fineness and high specific surface area is an effective means to improve early strength, but it will bring high energy consumption, high water demand and other disadvantages, especially high belite cement, which can make up for the problem of insufficient early strength by using the particle size distribution in the later stage, so pursuing optimized particle size distribution is a more scientific and economic method. Through technical means to control the content of coarse particles >30μm, and reasonably control the proportion of ultra-fine particles <3μm, while ensuring the early strength, higher later strength and better durability are obtained, and the traditional production method is a fixed production method, if the distribution of single particle size needs to be improved, the simplest way is to run the period of the later stage ball mill, if the content of ultra-fine particles needs to be increased, the grinding time needs to be increased, which will lead to the increase of production energy consumption, and if the content of coarse powder needs to be increased, it will lead to the substandard of overall particle size distribution, affecting the overall performance of the cement, therefore, the application is designed, specifically, including a batching bin 1 and a gypsum bin 2, the batching bin is a batching bin of the original production line, for clinker, desulfurization gypsum, fly ash, waste limestone and the like, the batching bin 1 and the gypsum bin 2 are connected with a mixed feeding bin 4 through a first conveying module 3, the above is conveyed through the first conveying module 3 according to the mixing ratio, and mixed in the conveying process, sent to the mixed feeding bin 4, and then stably and uniformly discharged through the mixed feeding bin 4, it is worth noting that the above raw materials of the application are mainly granular materials, and the fine ash such as fly ash is directly sent to the ball mill 11, the discharge end of the mixed feeding bin 4 is provided with a roller press 5, after the above raw materials are rolled by the roller press 5, the material is cracked and broken, the discharge end of the roller press 5 is connected with a multi-stage classification module 7 through an elevator 6, the multi-stage classification module 7 in the application can be selected to be connected in series with classification equipment such as scattering or air classification for classification, the material collides in the multi-stage classification module 7, further improves the crushing condition, and is divided into multiple stages according to the particle size, the fine powder discharge end of the multi-stage classification module 7 is connected in each bin of the classified bin 8 respectively, the multi-stage raw material is stored in each bin of the classified bin 8, waiting for specific classification, the tail part of the multi-stage classification module 7 is returned to the mixed feeding bin 4, in the powder selection process, the particle size greater than the screening requirement is circulated between the multi-stage classification module 7 and the roller press 5 until the particle size meets the requirement, improving the subsequent grinding quality; The material after grading is fed into the ball mills 11 through the second conveying modules 10 after being fed by the feeding module 9 under the grading bin 8. The feeding module 9 is a discharge system under the bin, which can control the weight and the feeding speed of the raw material. For details, please refer to the prior art. After receiving the system instruction, the material is fed into each second conveying module 10 according to the set proportion, and then is fed into each ball mill 11 for grinding. In this application, the ball mill 11 can be set to 2-3 units. One of them can be used to grind a large proportion of fine powder or the second type of fine powder and coarse powder with small power, to improve the grinding time and the production of ultra-fine powder, and to crush the large particle material. The other one grinds the medium powder to reduce the amount of large particles and fine powder, which can quickly complete the grinding of the material. The first-stage fine powder can also be directly fed into the mixing bin 17. The distribution principle is to distribute the finest group into the mixing bin 17. Since the particles are graded during grinding, the particle size distribution of each ball mill 11 is different. The particle size can be controlled by grading and grinding time. Therefore, the semi-finished product of the ball mill 11 is fed into the mixing bin 17 after being sorted by the scattering and grading machine 14. The particle size can be detected by a particle size detector. For details, please refer to the prior art. When configuring the finished product, according to the particle size of the raw material and the requirements of the finished product to be configured, the mixing bin 17 is connected with a mixer. Each semi-finished product is fed according to the required proportion of grading, mixed by the mixer, and stored in the finished product storage 21 according to different finished product requirements. Through the setting of this application, first, the particle size distribution in the cement can be controlled to make the RRSB distribution equation in engineering. The Rosin-Rammler-Sperling-Bennet (RRSB) distribution function is used to describe the particle size distribution of the cement. Its characteristic parameters are uniformity coefficient n and characteristic particle size D 63 .2。The larger the n value, the more concentrated the particle distribution, and the more uniform the particle size. The smaller the n value, the wider the particle distribution. Modern cement pursues a moderate and small n value. In this way, fine particles ensure early strength, medium particles ensure late strength, and coarse particles can reduce water demand and improve fluidity, achieving the balance of optimal grading of strength development and workability. Second, the energy consumption in the production process can be reduced. After grading, unnecessary grinding and grinding time can be reduced, thereby reducing the consumption of electric energy in the system. Third, without affecting the production capacity, different batches of low-heat portland cement can be produced for different application situations. In this application, the particle size distribution of the cement can be configured according to the specific construction situation, as shown in Figures 5-7 .

[0022] In the application, the fly ash storehouse 22 is directly connected with the ball mill 11, the fly ash powder in the system is directly sent to the ball milling process without entering the roller press, which can reduce the workload and useless work of the roller press 5, improve the stability of the system operation, improve the operation efficiency of the system, separate the fine powder, and improve the conveying efficiency of the raw materials in the early stage.

[0023] In the application, the semi-finished product of the ball mill 11 is sent to the scattering classifier 14 through the third conveying module 13, the scattering classifier 14 is usually arranged at other positions according to the actual situation of the production system, therefore, the material is conveyed through the third conveying module 13, which is convenient for the arrangement of the scene and the adjustment of the material speed entering the scattering classifier 14.

[0024] In the application, the backflow pipe 12 is arranged between the coarse material end of the scattering classifier 14 and the ball mill 11, some unqualified products appear in the ball milling process of the system, therefore, the scattering classifier 14 screens out part of the unqualified products in particle size, and the unqualified products are returned to the ball mill 11 through the backflow pipe 12 to be ground again, the backflow particle size can be controlled, and the quality of the subsequent finished product is improved.

[0025] In the application, the collecting bin 15 of the scattering classifier 14 is sent to the mixing bin 17 through the fourth conveying module 16, the specific selection and arrangement of the fourth conveying module 16 are determined according to the actual scene, therefore, various conveying modes are designed in the application Figure 2 according to the scene design.

[0026] In the application, the mixing machine is a spiral mixing machine 19, the raw materials are mixed in two steps in the secondary mixing, the first step is to enter the spiral mixing machine 19, the spiral mixing machine 19 has high mixing efficiency, the motor of the spiral mixing machine 19 is a variable frequency motor, which can be set according to the operation efficiency of the system, and can meet the production demand under different output, the mixed material is sent into the finished product storage 21 through the gas conveying mode after being mixed by the spiral mixing machine 19, the process is secondary mixing, so as to ensure the uniformity of the particle size of the finished product; Further, the spiral mixing machine 19 feeds through the buffer hopper 20, the buffer hopper 20 can ensure the stability of the feeding and ensure the continuous feeding, the mixing bin 17 feeds through the feeding hopper 18, the feeding hopper 18 is arranged to stabilize the feeding of the mixing bin 17, other conveying equipment can be arranged between the buffer hopper 20 and the feeding hopper 18 to improve the stability of the whole system.

[0027] In the application, the multi-stage grading module 7 is divided into four stages of discharging. Through the four-stage filtration, the two ends of the raw materials can be graded. The finest material can be used as a semi-finished product for storage, or can be distributed to other levels according to the product demand, to stabilize the stability of the finished particle size. The largest diameter raw material can be used alone as a powder, or combined with a small amount of fine powder. The specific combination is determined according to the actual test results. The middle particle size is divided into two groups. One is to further refine the particle size distribution, and the other is to facilitate more detailed grading during batching, thereby facilitating the control of the particle size after ball milling, and realizing the adjustment of more particle size parameters. During specific grading, the particle size of the four-stage discharge is 0-30, 30-120, 120-300, and 300-450. This grading can improve the control of the particle size of the cement particles. During the secondary mixing, the fine particles are adjusted. According to the actual situation, if sufficient early strength is required, the <3μm or <5μm micron particle size distribution is increased, which is mainly responsible for the early strength (such as 3-day and 7-day strength). These particles have extremely fast hydration speed and can generate a large amount of C-S-H gel in a short time, rapidly building the early skeleton structure of the cement stone. However, the specific surface area of the fine particles is large, and more water is needed to wet and maintain the same construction fluidity. High water demand will increase the porosity of the cement stone, which is not conducive to the later strength, and will increase the risk of cracking of mass concrete. Excellent later strength is required to increase the particle size distribution of 5-115μm, which is the most critical part of the later strength (28-day and later strength). These particles have moderate hydration speed and can continuously and stably hydrate, constantly filling the pores formed in the early stage, making the cement stone structure more dense, thereby significantly improving the later strength. At the same time, the particles of 3-30μm should account for the majority (such as more than 65%), thereby ensuring the good construction performance of the cement.

[0028] A preparation method of high-berlitt low-heat Portland cement, comprising the following steps: S1, the cement raw materials are configured by the batching bin 1 according to the set proportion, and are sent to the mixing upper bin 4 by the conveying module and are rolled by the roller press 5. The raw materials are mixed in the mixing upper bin 4, and then are discharged according to the actual working performance of the roller press 5. The output of the system can be adjusted in the initial stage. S2, the rolled materials are sent to the multi-stage grading module 7, the rolled raw materials are divided into multiple stages, and the raw materials are graded and stored according to the set particle size value. The particle size distribution can be adjusted by the working power of the roller press 5. For example, when the finest stage in the system is insufficient, the pressure of the roller press 5 can be increased to make the raw materials more crushed. Conversely, the stability of each stage can be controlled, and the tailings of unqualified particles are recycled to the roller press 5 for continuous rolling. S3, after the raw material roller is pressed and classified, the raw material of each level is configured to be sent to the ball mill according to the set proportion, the final raw material particle size can be controlled through the classification of different particle sizes and the ball milling time, the ball milling process is classified, and the particle size distribution of the raw material can be controlled and refined; S4, the raw material after ball milling is classified again to obtain semi-finished product and tailings, the semi-finished product is stored, and the tailings are returned to the ball mill, so that the material after ball milling needs to be screened, therefore, when controlling, whether the distribution of qualified particle size meets the requirements can be considered, so that the ball milling time can be shortened, and it is worth noting that the amount of material returned to the ball mill for regrinding should be optimally matched with the working capacity of the ball mill, that is, the energy consumption caused by the return amount should not be greater than the energy consumption saved by improving the ball milling efficiency, so as to cause the phenomenon of inverting the end. S5, the semi-finished product in each ball mill is mixed according to the set proportion, the refined particle size is classified again through the secondary mixing, the particle size distribution of the material is further controlled, so that the product is obtained, and the product is stored for application in different scenes, and the particle size distribution is optimized: a more scientific and more economical method. Through technical means, the content of coarse particles not participating in hydration is reduced, and the proportion of superfine particles is reasonably controlled, so that higher later strength and better durability are obtained while the early strength is ensured, such as Figure 8 As shown in the figure, after the fineness classification is controlled, not only the early strength of the cement can be improved, but also the later strength of the cement can be ensured, so that the overall performance of the cement is improved.

[0029] From the above technical solutions, it can be seen that, through the classification and distribution on the cement production line, the product performance can be randomly distributed without affecting the production capacity, specifically, in the batching stage, the raw materials are mixed and fed into the mixing feeding bin through the conventional batching bin 1, then the raw materials are rolled by the roller 5, then the raw materials are classified by the multi-stage classification module 7 according to the particle size, the raw materials are classified by four stages, then the four-stage raw materials are matched according to the set proportion, and then the raw materials are sent to different ball mills 11 for ball milling, the material after ball milling is stored after screening, and then the material is mixed again according to the particle size, in fact, the particle size distribution of the mixed product meets the design requirements, so that the diversified production requirements are met.

[0030] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the application cover any variations, uses, or adaptations of the application following, in general, the principles of the application and including such departures from the application that come within known

[0031] It should be understood that the application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The foregoing described embodiments of the application are not to be construed as limiting the application.

Claims

1. A system for producing a high belite low heat Portland cement, characterized by: Including the ingredient warehouse (1) and the gypsum warehouse (2), the ingredient warehouse (1) and the gypsum warehouse (2) are connected with the mixed upper feed bin (4) by the first conveying module (3), the discharge end of the mixed upper feed bin (4) is installed with the roller press (5), the discharge end of the roller press (5) is connected with the multi-stage grading module (7) by the elevator (6), the fine powder discharge end of the multi-stage grading module (7) is connected in each bin of the grading bin (8) respectively, the tail coarse material of the multi-stage grading module (7) is returned to the mixed upper feed bin (4), the grading bin (8) is dosed by the ingredient module (9) and then is sent to multiple ball mills (11) by multiple second conveying modules (10) respectively, the semi-finished product material of the ball mill (11) is sorted by the dispersing classifier (14) and then enters the mixing bin (17), multiple mixing bins (17) are connected with the mixer, and the mixer is connected with multiple finished product storage libraries (21).

2. The system for producing a high-berlinitz low heat portland cement according to claim 1, wherein There is also a fly ash warehouse (22) directly connected with the ball mill (11).

3. The system for producing a high-berlinitz low heat portland cement according to claim 1, wherein, The semi-finished product material of the ball mill (11) is sent to the dispersing classifier (14) by the third conveying module (13).

4. The system for producing a high belite low heat Portland cement according to claim 3, wherein The coarse material end of the dispersing classifier (14) and the ball mill (11) are also provided with a return pipe (12).

5. The system for producing a high-berlinitz low heat portland cement according to claim 4, wherein The collecting bin (15) of the dispersing classifier (14) is sent to the mixing bin (17) by the fourth conveying module (16).

6. The system for producing a high-berliti low heat portland cement according to claim 1, wherein The mixer is a spiral mixer (19).

7. The system for producing a high-berliti low heat portland cement according to claim 6, wherein The spiral mixer (19) feeds through the buffer hopper (20), and the mixing bin (17) discharges through the feeding hopper (18).

8. The system for producing a high-berliti low heat portland cement according to claim 1, wherein The multi-stage grading module (7) is divided into four-stage discharge.

9. The system for producing a high-berlinitz low heat portland cement according to claim 8, characterized in that, The particle size of the four-stage discharge is 0-30, 30-120, 120-300 and 300-450.

10. A method of producing a high belite low heat Portland cement, characterized by, The method comprises the following steps: S1, according to the set proportion, the cement raw material is configured by the ingredient warehouse (1), and is sent to the mixed upper feed bin (4) by the conveying module and enters the roller press (5) for roller pressing; S2, the material after roller pressing is sent to the multi-stage grading module (7), and the raw material is graded and stored according to the set particle size value; S3, according to the set proportion, the raw material of each stage is configured and sent to the ball mill; S4, the raw material after ball milling is graded again to obtain semi-finished product material and tail material, the semi-finished product material is stored, and the tail material is returned to the ball mill; S5, according to the set proportion, the semi-finished product material in each ball mill is mixed twice to obtain finished product material, which is stored respectively.

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