Fly ash doping production process for cement

Abstract

The invention discloses cement doped with fly ash, which comprises the following raw materials: 60-80% of common clinker; 3%-7% of desulfurized gypsum; 5%-10% of fly ash; 2%-8% of limestone; 5%-15% of water granulated slag; 0.05%-0.2% of a grinding aid; the invention relates to a fly ash doping production process for cement. The process comprises the following steps: fly ash is discharged from a fly ash storage, is metered by a pneumatic flow control valve and a solid flow meter, and then enters an air conveying chute under the storage; conveying the fly ash to a return powder air conveying chute of the powder concentrator through a fly ash air conveying chute at the platform, mixing the fly ash with return powder, and grinding in a mill; fully mixing and grinding the mixture in a mill until the specified fineness is reached; and the ground cement is screened by a powder concentrator and then passes through a finished product dust collector, and the finished product cement is conveyed to a cement finished product storage cavern through an air conveying chute and an elevator. A closed steady flow bin feeding technology is adopted, so that the stable and uniform fly ash adding speed is ensured, and the production efficiency and the product quality are improved.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, in particular to a fly ash admixture production process for cement. Background Art

[0003] Fly ash is the fine ash collected from the flue gas after coal combustion. It is the main solid waste discharged from coal-fired power plants. If a large amount of fly ash is not treated, it will produce dust and pollute the atmosphere. If it is discharged into the water system, it will cause river siltation, and the toxic chemicals in it will also cause harm to humans and organisms.

[0004] The company uses fly ash as a mixing material to produce environmentally friendly cement and realize comprehensive resource recycling. The dry fly ash from the original two cement mills is directly discharged from the storage tank and transported to the cement mill to participate in the batching. However, due to the good fluidity of dry fly ash and uncontrolled discharge, the use of traditional feeding methods leads to unstable metering, affecting the stability of the cement component ratio. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the above technical defects and provide a fly ash admixture production process for cement.

[0006] In order to solve the above problems, the technical solution of the present invention is: a cement mixed with fly ash, comprising the following raw materials in percentage by mass:

[0007] Ordinary clinker: 60%-80%;

[0008] Desulfurized gypsum: 3%-7%;

[0009] Fly ash: 5%-10%;

[0010] Limestone: 2%-8%;

[0011] Water slag: 5%-15%;

[0012] Grinding aid: 0.05%-0.2%.

[0013] Furthermore, the fly ash is fine ash collected from flue gas emitted by coal-fired power plants and is screened and impurity-removed.

[0014] Furthermore, the fly ash is screened, classified and dried, and particles with a particle size of less than 45 microns account for no less than 90%.

[0015] A fly ash admixture production process for cement comprises the following steps:

[0016] S1. Transport the fly ash that meets the quality requirements to the fly ash storage, and transport the mixed materials such as clinker, desulfurized gypsum, limestone, slag, etc. to the stabilizing bin respectively;

[0017] S2, the fly ash is discharged from the fly ash storage tank and then measured by the pneumatic flow control valve and solid flow meter and then enters the air conveying chute under the storage tank;

[0018] S3, transport the fly ash to the powder selector return air conveying chute platform through the elevator;

[0019] S4, transporting the fly ash through the fly ash air conveying chute at the platform to the return powder air conveying chute of the powder selector and mixing it with the return powder into the mill for grinding;

[0020] S5, fully mixing and grinding the mixture in a mill and grinding to a specified fineness;

[0021] S6. The ground cement is screened by the powder selector and then passed through the finished product dust collector. The finished cement is then transported to the cement finished product storage through the air conveying chute and elevator.

[0022] Furthermore, in step S1, the fly ash enters the steady flow bin through the closed spiral gate and the aerated discharge box under the bin. The closed steady flow bin feeding technology is adopted to make the dry fly ash addition rate stable and uniform, and the grinding aid is added by the grinding head.

[0023] Furthermore, in step S6, the ground mixture is lifted to the inlet of the powder concentrator by the mill elevator and discharged, and the ground mixture is discharged into the powder concentrator.

[0024] Furthermore, in step S1, the fly ash must be weighed by an electronic truck scale before being added into the factory, and must be sampled and tested by the laboratory before being put into storage.

[0025] Furthermore, in step S5, the fineness of the cement is required to be 5%-10% of the residue on the 80 μm square hole sieve.

[0026] Furthermore, the storage condition in step S6 is confirmed by cement quality, and the cement quality confirmation standard is in accordance with the "General Portland Cement Factory Confirmation Method" GB / T 39698-2020, and the inventory cement is shipped in bulk or bagged.

[0027] The advantages of the present invention compared with the prior art are:

[0028] 1. The present invention provides a fly ash blending production process for cement, which effectively utilizes the fly ash discharged from coal-fired power plants as one of the raw materials for cement production, thereby not only reducing the stacking and processing costs of fly ash, but also alleviating the pollution problem of fly ash to the environment, realizing the resource utilization of waste, and conforming to the development concept of circular economy;

[0029] 2. The present invention provides a fly ash blending production process for cement. The silicon and aluminum components in the fly ash can exert a volcanic ash effect during the cement hydration process, which helps to improve the later strength, impermeability and durability of the cement, making the produced cement product have better performance. The fly ash has a small particle size and is evenly distributed, which is conducive to the close stacking of cement particles, reduces porosity, and improves the density and strength of cement.

[0030] 3. The present invention provides a fly ash admixture production process for cement, which adopts a closed flow stabilization bin feeding technology to ensure a stable and uniform fly ash addition rate, effectively avoid production fluctuations caused by material flow fluctuations, and improve production efficiency and product quality;

[0031] 4. The present invention provides a fly ash admixture production process for cement, which ensures the homogeneity and stability of cement products by finely controlling the grinding fineness of cement (such as 5%-10% residue on an 80μm square hole sieve), thereby meeting the specific requirements of different projects for cement performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a flow chart of a fly ash admixture production process for cement.

[0033] Figure 2 It is a statistical line graph of three groups of 3-day compressive strength data of cement added with fly ash according to the present invention.

[0034] Figure 3 The present invention is a statistical line graph of three groups of cement qualified rate data added with fly ash cement. DETAILED DESCRIPTION

[0035] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices consistent with some aspects of the present disclosure as detailed in the appended claims.

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0037] A cement mixed with fly ash, comprising the following raw materials in percentage by mass:

[0038] Ordinary clinker: 60%-80%;

[0039] Desulfurized gypsum: 3%-7%;

[0040] Fly ash: 5%-10%;

[0041] Limestone: 2%-8%;

[0042] Water slag: 5%-15%;

[0043] Grinding aid: 0.05%-0.2%.

[0044] Furthermore, the fly ash is screened, classified and dried, and the proportion of particles with a particle size of less than 45 microns is not less than 90%.

[0045] Furthermore, fly ash is fine ash collected from flue gas emitted by coal-fired power plants and is screened and impurity-removed.

[0046] A fly ash admixture production process for cement comprises the following steps:

[0047] S1. Transport the fly ash that meets the quality requirements to the fly ash storage, and transport the mixed materials such as clinker, desulfurized gypsum, limestone, slag, etc. to the stabilizing bin respectively;

[0048] S2, the fly ash is discharged from the fly ash storage tank and then measured by the pneumatic flow control valve and solid flow meter and then enters the air conveying chute under the storage tank;

[0049] S3, transport the fly ash to the powder selector return air conveying chute platform through the elevator;

[0050] S4, transporting the fly ash through the fly ash air conveying chute at the platform to the return powder air conveying chute of the powder selector and mixing it with the return powder into the mill for grinding;

[0051] S5, fully mixing and grinding the mixture in a mill and grinding to a specified fineness;

[0052] S6. The ground cement is screened by the powder selector and then passed through the finished product dust collector. The finished cement is then transported to the cement finished product storage through the air conveying chute and elevator.

[0053] Furthermore, in step S1, the fly ash must be weighed by an electronic truck scale before being added into the factory, and then put into storage after being sampled and tested by the laboratory and qualified.

[0054] Furthermore, in step S1, the fly ash enters the steady flow bin through the closed spiral gate and the aerated discharge box under the bin, and the closed steady flow bin feeding technology is adopted to make the dry fly ash addition rate stable and uniform, and the grinding aid is added by the grinding head.

[0055] Furthermore, in step S5, the fineness of the cement is required to be 5%-10% of the residue on the 80 μm square hole sieve.

[0056] Furthermore, in step S6, the ground mixture is lifted to the inlet of the powder classifier by the mill elevator and discharged, and the ground mixture is discharged into the powder classifier.

[0057] Furthermore, the storage condition in step S6 is confirmed by cement quality, and the cement quality confirmation standard is in accordance with the "General Portland Cement Factory Confirmation Method" GB / T 39698-2020, and the inventory cement is shipped in bulk or bagged.

[0058] The detailed experimental control data are shown in Table 1:

[0059] type Ordinary clinker Desulfurization gypsum Fly ash limestone Water slag Grinding Aids Experiment 1 55％ 8％ 15％ 10％ 12％ 0.3％ Experiment 2 76％ 5.5％ 4.5％ 4.5％ 7.5％ 0.001％ Experiment 3 85％ 2％ 2％ 4％ 7％ 0.05％

[0060] Table 1

[0061] The comparison structure of the three sets of experimental data is as follows Figure 2 The detailed results are as follows:

[0062] The data results of Experiment 1 showed that the 3-day compressive strength of cement was 28Mpa, and the qualified rate of cement admixture increased to 95%.

[0063] The data results of Experiment 2 are as follows: the 3-day compressive strength is 20Mpa, the qualified rate of cement admixture is 88%, the concrete workability is good, but the early strength is low, the production cost is significantly reduced, but the cement quality stability is poor, the mill output is high, and the power consumption is relatively low.

[0064] The data results of Experiment 3 are as follows: the 3-day compressive strength is 30Mpa, the qualified rate of cement admixture is 98%, the workability of concrete is general, more heat is released during the hardening process and cracks are easily generated, the production cost is high, because the amount of fly ash used is small, its economic advantages are not fully utilized, the output of the mill is low, and the power consumption is relatively high.

[0065] Through the comparison of the above experimental data, it can be seen that the addition of fly ash under reasonable proportion can not only improve the early strength of cement and the qualified rate of admixtures, but the silicon and aluminum components in fly ash can play a volcanic ash effect in the cement hydration process, which is helpful to improve the later strength, impermeability and durability of cement, making the produced cement products have better performance. The particle size of fly ash is small and evenly distributed, which is conducive to the close stacking of cement particles, reducing porosity, and improving the density and strength of cement. By using the closed steady flow bin feeding technology applied to the open feeding of fly ash, and improving the metering and conveying facilities, the addition rate of dry fly ash can be stable and uniform, thereby improving the stability of cement quality.

[0066] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0067] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0068] The present invention and its embodiments are described above, and such description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A cement added with fly ash, characterized in that: The following raw materials are included in mass percentage: Ordinary clinker: 60%-80%; Desulfurized gypsum: 3%-7%; Fly ash: 5%-10%; Limestone: 2%-8%; Water slag: 5%-15%; Grinding aid: 0.05%-0.2%.

2. The fly ash admixture production process for cement according to claim 1, characterized in that: The fly ash is screened, classified and dried, and particles with a particle size of less than 45 microns account for no less than 90%.

3. The fly ash admixture production process for cement according to claim 1, characterized in that: The fly ash is fine ash collected from flue gas discharged from coal-fired power plants and is screened and impurity-removed.

4. A production process for adding fly ash to cement, characterized in that: The following steps are involved: S1. Transport the fly ash that meets the quality requirements to the fly ash storage, and transport the mixed materials such as clinker, desulfurized gypsum, limestone, slag, etc. to the stabilizing bin respectively; S2, the fly ash is discharged from the fly ash storage tank and then measured by the pneumatic flow control valve and solid flow meter and then enters the air conveying chute under the storage tank; S3, transport the fly ash to the powder selector return air conveying chute platform through the elevator; S4, transporting the fly ash through the fly ash air conveying chute at the platform to the return powder air conveying chute of the powder selector and mixing it with the return powder into the mill for grinding; S5, fully mixing and grinding the mixture in a mill and grinding to a specified fineness; S6. The ground cement is screened by the powder selector and then passed through the finished product dust collector. The finished cement is then transported to the cement finished product storage through the air conveying chute and elevator.

5. A fly ash admixture production process for cement according to claim 4, characterized in that: In step S1, the fly ash must be weighed by an electronic truck scale before being added into the factory, and then put into the storage after being sampled and tested by the laboratory and qualified.

6. A fly ash admixture production process for cement according to claim 4, characterized in that: In the step S1, the fly ash enters the steady flow bin through the closed spiral gate and the aerated discharge box under the bin. The closed steady flow bin feeding technology is adopted to make the dry fly ash adding rate stable and uniform, and the grinding aid is added by the grinding head.

7. A fly ash admixture production process for cement according to claim 4, characterized in that: The fineness requirement of the cement in step S5 is 5%-10% of the residue on the 80 μm square hole sieve.

8. The fly ash admixture production process for cement according to claim 4, characterized in that: In step S6, the ground mixture is lifted to the inlet of the powder concentrator by the mill elevator and discharged, and the ground mixture is discharged into the powder concentrator.

9. A fly ash admixture production process for cement according to claim 4, characterized in that: The storage condition in step S6 is that the cement quality is confirmed, and the cement quality confirmation standard is in accordance with the "General Portland Cement Factory Confirmation Method" GB / T 39698-2020, and the inventory cement is shipped in bulk or bagged.

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