Cement grinding aid and preparation method thereof

Abstract

The invention belongs to the technical field of cement grinding aid preparation, and particularly relates to a cement grinding aid and a preparation method thereof. The cement grinding aid provided by the invention comprises the raw materials of water, hydrogen peroxide and sodium stannate, by scientifically regulating and controlling the synergistic effect of the components, the cement grinding aid has good grinding aiding performance, remarkably improves the cement strength and grinding aiding efficiency and reduces energy consumption, and more importantly, the component design of the cement grinding aid is considered based on a systematic mechanism; the grinding efficiency is improved by reducing the particle surface energy and weakening the lattice strength, and the rheological property of the powder is improved by utilizing the mechanochemical effect, so that the internal friction force is reduced; in the aspect of macroscopic performance, the cement hydration process is promoted, and the grain composition and the set cement microstructure are optimized; finally, the design ensures that the product can exert stable and efficient grinding aiding and enhancing effects under different cement compositions and grinding process parameters.

Description

Technical Field

[0001] This invention belongs to the field of cement grinding aid preparation technology, and more specifically relates to a cement grinding aid and its preparation method. Background Technology

[0002] Cement is an indispensable basic building material in modern society. Its production process typically involves key steps such as grinding and firing, with cement grinding being the core step that determines the final product's performance and production energy consumption. Statistics show that the electricity consumption of the cement grinding process accounts for approximately 60% to 75% of the total electricity consumption in cement production, making it a key area for energy conservation and emission reduction in the cement industry. Therefore, improving grinding efficiency, reducing energy consumption per unit product, and simultaneously improving the quality of finished cement products (such as strength and particle size distribution) have always been important directions for technological research and development in the industry.

[0003] Against this backdrop, the application of cement grinding aids has become one of the key technical means to achieve the above-mentioned goals. Grinding aids, by adsorbing onto the surface of cement particles during the grinding process, can reduce the surface energy of the particles, prevent fine particle agglomeration, and weaken particle strength, thereby significantly improving grinding efficiency and often having a positive impact on the later-stage strength development of cement. Currently, the cement grinding aids widely used in the market are mostly alkanolamine compounds (such as triethanolamine and triisopropanolamine). While these traditional grinding aids can play a role in grinding and strengthening to some extent, they have gradually revealed several technical bottlenecks and limitations in long-term application: First, their strengthening effect, especially the improvement in early strength, often fails to meet the requirements for the preparation of high-performance cement; second, their adaptability and stability are sometimes insufficient for cement varieties prepared with different blends or processes, resulting in significant fluctuations in performance; third, some alkanolamine raw materials are expensive, and their production or use may involve certain environmental concerns; in addition, traditional grinding aids have relatively limited potential in optimizing cement particle size distribution and improving the microstructure of cement stone, and their targeting in promoting the hydration of specific mineral phases (such as C3A and C4AF) is not strong, thus limiting their further improvement in the overall performance of cement.

[0004] Therefore, there is an urgent need in this field to develop a new type of cement grinding aid that not only has excellent grinding performance to effectively reduce grinding energy consumption, but also significantly improves the mechanical properties of cement (especially early and late strength), and has good adaptability and stability to a variety of common cement types. Summary of the Invention

[0005] The purpose of this invention is to provide a cement grinding aid and its preparation method, and more specifically, to provide a novel liquid cement grinding aid and its preparation method, so as to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention: provides a cement grinding aid, comprising, by weight, the following raw materials: 80-100 parts water, 15-20 parts hydrogen peroxide, and 0.5-2 parts sodium stannate.

[0007] Furthermore, the concentration of the hydrogen peroxide is 18%.

[0008] Furthermore, the cement grinding aid, by weight, comprises the following raw materials: 80 parts water, 20 parts hydrogen peroxide and 0.5 parts sodium stannate, or 90 parts water, 15 parts hydrogen peroxide and 1.5 parts sodium stannate, or 100 parts water, 18 parts hydrogen peroxide and 2 parts sodium stannate.

[0009] The second technical solution of the present invention provides a method for preparing the above-mentioned cement grinding aid, comprising the following steps: Hydrogen peroxide and water are mixed and stirred evenly, then sodium stannate is added, and the mixture is stirred and reacted to obtain the cement grinding aid.

[0010] Furthermore, the time for mixing is 2 minutes.

[0011] Furthermore, the stirring reaction time is 2 minutes.

[0012] The third technical solution of the present invention provides an application of the above-mentioned cement grinding aid in the preparation of cement products, wherein the amount of cement grinding aid added in the preparation of cement products is 0.03-0.05wt.

[0013] This cement grinding aid can improve grinding efficiency and enhance product performance by reducing the surface energy of cement particles and decomposing and weakening the strength of the particles during the preparation of cement products.

[0014] The fourth technical solution of the present invention provides a method for preparing cement, wherein the above-mentioned cement grinding aid is added at an amount of 0.03-0.05 wt% to produce cement products.

[0015] Furthermore, the cement products include silicate cement, ordinary cement, slag cement, fly ash cement, pozzolanic cement, composite cement, or road cement.

[0016] The present invention discloses the following technical effects: The OO and OH bonds in the cement grinding aid provided by this invention can interact with the Ca atoms on the surface of cement particles. 2+ Al 3+ Fe 3+When metal ions coordinate, they form stable coordination compounds, effectively reducing particle surface energy, weakening internal chemical bonds, and improving grinding efficiency. Simultaneously, grinding aid molecules adsorb onto the surface of cement particles, forming a uniform protective film that significantly improves particle dispersibility, prevents fine particle agglomeration, enhances powder flowability, reduces bubble generation during grinding, decreases pore area between bubbles, improves powder permeability, and optimizes bulk density.

[0017] During the cement hydration stage, this grinding aid promotes the hydration reaction of the main mineral phases (C3S, C3A, C2S, C4AF), accelerates the formation of hydration products, and has a particularly significant promoting effect on C3A hydration and ettringite formation. Furthermore, it optimizes cement particle size distribution, effectively increasing the content of particles in the 3-32μm key particle size range by approximately 5%-10%, reducing over-grinding, increasing the specific surface area of ​​cement, enhancing the contact efficiency between cement and water, and thus optimizing the microstructure of cement stone: promoting the formation and development of CSH gel, increasing its content, refining the Ca(OH)2 crystal size, reducing the proportion of macropores, and improving the density and mechanical properties of cement stone. Experiments show that cement products incorporating 0.03%-0.05% of this grinding aid can increase the 3-day compressive strength by 1.5-5.0 MPa and the 28-day compressive strength by 1.5-4.6 MPa, while simultaneously improving grinding efficiency by 6.8%-13.6%. The preparation process of this invention is simple, low-cost, and easy to implement industrially, and has good prospects for promotion and application. Detailed Implementation

[0018] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0019] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0020] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0021] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0022] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0023] Unless otherwise specified, all raw materials and reagents involved in the specific embodiments of this invention are commercially available products.

[0024] Unless otherwise specified, room temperature and ambient temperature in the specific embodiments of this invention refer to 5-38℃.

[0025] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0026] In some specific embodiments, the present invention provides a method for preparing a cement grinding aid, the steps of which include: S1. Prepare raw materials by weight: 80-100 parts water, 15-20 parts hydrogen peroxide and 0.5-2 parts sodium stannate; The hydrogen peroxide concentration was 18%. S2. Put water into the mixing tank, then add hydrogen peroxide to the mixing tank and stir continuously for 2 minutes. Then add sodium stannate and stir for another 2 minutes to carry out the mixing reaction and obtain cement grinding aid.

[0027] The cement grinding aid prepared by this invention is formulated by mixing hydrogen peroxide, water, and sodium stannate in a specific ratio. Through scientific regulation of the synergistic effect of each component, it not only possesses excellent grinding aid performance, significantly improves cement strength and grinding efficiency, and reduces energy consumption, but more importantly, its component design is based on systematic mechanistic considerations: at the microscopic level, it improves grinding efficiency by reducing particle surface energy and weakening lattice strength, and utilizes mechanochemical effects to improve powder rheological properties and reduce internal friction; at the macroscopic level, it aims to promote cement hydration process and optimize particle size distribution and cement stone microstructure; ultimately, this design ensures that the product can exert stable and efficient grinding aid and strengthening effects under different cement compositions and grinding process parameters.

[0028] Hydrogen peroxide has self-decomposing properties and is extremely sensitive to thermal vibration, impact, or friction. When subjected to slight external force, it decomposes and organically combines with the mineral components and water molecules in the sodium stannate stabilizer. This grinding aid primarily improves grinding efficiency by reducing the surface energy and weakening the strength of cement particles through the self-decomposing substances in the cement and the formation of minerals in the stabilizer. During the grinding process, cement particles are subjected to mechanical stress, causing cracks and decomposition, ultimately leading to particle breakage. When the grinding aid molecules adsorbed on the particle surface or crack surface decompose, they reduce the surface area and strength of the particles, making the cement particles easier to decompose and improving grinding efficiency. Specifically: The OO and OH bonds in hydrogen peroxide molecules can bind with the Ca atoms on the surface of cement particles. 2+ A1 3+ Fe 3+ When metal ions coordinate, stable coordination compounds are formed. This coordination not only reduces the surface energy of the particles but also weakens the internal chemical bonds, making the particles easier to refine. This improves particle dispersibility and eliminates agglomeration. Hydrogen peroxide-based grinding aids can adsorb onto the surface of cement particles, forming a protective film that reduces surface tension between particles, thus preventing agglomeration. Furthermore, the polar groups of hydrogen peroxide molecules can neutralize the surface charge of particles and reduce electrostatic attraction between particles, further improving particle dispersibility. Specifically, the crystal groups in hydrogen peroxide molecules have strong polarity, enabling them to form ionic or hydrogen bonds with the surface charge of cement particles, neutralizing the surface charge, reducing the zeta potential, and thus reducing electrostatic attraction between particles. Therefore, this improves grinding efficiency and cement quality.

[0029] The cement grinding aid prepared by this invention can significantly reduce the surface tension and viscosity of cement particles, improve the flowability of cement powder, reduce friction and agglomeration between particles, and improve grinding efficiency. Furthermore, hydrogen peroxide-based grinding aids can reduce the air bubbles generated during grinding, decrease the pore area between air bubbles, make the surface of cement particles smoother, further improve the uniformity of grinding action on the particles, improve the flowability of cement powder, reduce the internal friction and viscous resistance of the powder, making the powder easier to flow and disperse in the mill, forming a lubricating film, changing the pore structure of the powder, increasing the air permeability of the powder, and reducing the bulk density of the powder. Hydrogen peroxide-based grinding aids can not only improve the physical properties of the powder, but also change the mineral structure and activity of cement through chemical reaction with cement particles. During the cement grinding process, the grinding aid molecules will chemically react with the surface of cement particles to form a chemical adsorption layer. This chemical adsorption layer can not only promote the hydration of certain mineral phases in cement, such as C3A and C4AF, but also form some intermediate products. These intermediate products have low hardness and are easier to decompose. Therefore, this is the core factor that makes the grinding aid of this invention superior to the performance of alkanolamine-based cement grinding aids on the market.

[0030] Example 1 The preparation method of cement grinding aid includes the following steps: S1. Prepare the raw materials according to the following proportions by weight: 80 parts water, 20 parts hydrogen peroxide, and 0.5 parts sodium stannate; The hydrogen peroxide concentration was 18%. S2. Put water into the mixing tank, then add hydrogen peroxide to the mixing tank and stir continuously for 2 minutes. Then add sodium stannate and stir for another 2 minutes to carry out the mixing reaction and obtain cement grinding aid.

[0031] Example 2 The preparation method of cement grinding aid includes the following steps: S1. Prepare the raw materials according to the following proportions by weight: 90 parts water, 15 parts hydrogen peroxide, and 1.5 parts sodium stannate; The hydrogen peroxide concentration was 18%. S2. Put water into the mixing tank, then add hydrogen peroxide to the mixing tank and stir continuously for 2 minutes. Then add sodium stannate and stir for another 2 minutes to carry out the mixing reaction and obtain cement grinding aid.

[0032] Example 3 The preparation method of cement grinding aid includes the following steps: S1. Prepare the raw materials by weight: 100 parts water, 18 parts hydrogen peroxide and 2 parts sodium stannate; The hydrogen peroxide concentration was 18%. S2. Put water into the mixing tank, then add hydrogen peroxide to the mixing tank and stir continuously for 2 minutes. Then add sodium stannate and stir for another 2 minutes to carry out the mixing reaction and obtain cement grinding aid.

[0033] Experimental Example 1 The cement grinding aid and alkanolamine cement grinding aid (purchased from Anhui New Material Grinding Aid Co., Ltd.) prepared in Example 1 were used at 0.03% of the total cement weight to produce P·I type silicate cement, P·O type ordinary cement, and P·S type slag cement. The raw material ratio was prepared in accordance with the technical specifications of national standard GB / T175-2023. The technical indicators such as cement mortar strength were tested in accordance with GB / 17671. The test results are shown in Table 1.

[0034] Table 1 As shown in Table 1, when the cement grinding aid of Example 1 of this invention is used to replace commercially available alkanolamine cement grinding aids in the production of silicate cement, ordinary cement, and slag cement, the product quality is significantly improved compared to commercially available grinding aids. The cement products with the addition of this novel cement grinding aid exhibit a 0.2-0.4% reduction in fineness and an increase in specific surface area of ​​5-30 m². 2 / kg, reduces standard consistency water consumption by 1.2-1.6%, increases mortar fluidity by 25-55mm, improves compatibility by 10-20mm, shortens initial setting time by 5-20min, increases cement flexural strength by 0.2-0.5 MPa at 3 days and 0.3-0.5 MPa at 28 days, increases compressive strength by 1.1-2.5 MPa at 3 days and 1.5-2.0 MPa at 28 days, and improves grinding efficiency by 6.8-11.2%.

[0035] Experimental Example 2 The cement grinding aid and alkanolamine cement grinding aid (purchased from Anhui New Material Grinding Aid Co., Ltd.) prepared in Example 2 were used to produce P·F type fly ash cement and P·P type pozzolanic cement at 0.04% of the total cement weight. The raw material ratio was prepared in accordance with the technical specifications of national standard GB / T175-2023. The technical indicators such as cement mortar strength were tested in accordance with GB / 17671. The test results are shown in Table 2.

[0036] Table 2 As shown in Table 2, the cement grinding aid of Example 2 exhibits excellent adaptability to the quality of fly ash cement and pozzolanic cement products. It demonstrates significant water-reducing effects, lowers fineness, increases specific surface area, improves fluidity and compatibility, shortens setting time, and exhibits stable performance. The grinding aid's enhancement and efficiency are very significant, far exceeding the results obtained by adding commercially available amine grinding aids. Specifically, compared to commercial grinding aids, the fineness of cement products using this invention's grinding aid is reduced by 0.4-0.5%, and the specific surface area is increased by 66-70 m². 2 / kg, reducing standard consistency water consumption by 1.8-3.2%, improving fluidity by 16-20mm and compatibility by 15-30mm, shortening initial setting time by 10-15min and final setting time by 15-20min, increasing 3-day flexural strength by 0.4-0.5MPa and 28-day flexural strength by 0.6-0.7MPa, increasing 3-day compressive strength by 2.5-3.5MPa and 28-day compressive strength by 2.3-2.9MPa, and also increasing mill hourly efficiency by 8.9-13.1%.

[0037] Experimental Example 3 The cement grinding aid and alkanolamine cement grinding aid (purchased from Anhui New Material Grinding Aid Co., Ltd.) prepared in Example 3 were used at 0.05% of the total cement weight to produce P·C type composite cement and P·R type road cement. The raw material ratio was prepared in accordance with the technical specifications of national standard GB / T175-2023. The technical indicators such as cement mortar strength were tested in accordance with GB / 17671. The test results are shown in Table 3.

[0038] Table 3 As shown in Table 3, the cement grinding aid of Example 3 exhibits excellent adaptability to the performance of composite cement and road cement products. It demonstrates stable performance in terms of cement fineness, specific surface area, water consumption, fluidity, compatibility, setting time, flexural strength, and compressive strength. It reduces fineness and water consumption while improving reinforcement and grinding efficiency, which is far superior to using commercially available grinding aids. Specifically, compared to commercially available grinding aids, cement products using this novel cement grinding aid show a 0.5-0.6% reduction in fineness and an increase in specific surface area of ​​30-40 m². 2 / kg, reduces standard consistency water consumption by 1.8-2.2%, improves fluidity by 15-25 min and compatibility by 20-25 mm, shortens initial setting time by 20-25 min and final setting time by 20-30 min, increases cement flexural strength by 0.4-0.5 MPa at 3 days, flexural fineness by 0.5-0.6 MPa at 28 days, compressive strength by 4.6-5.0 MPa at 3 days, compressive strength by 4.0-4.6 MPa at 28 days, and improves grinding efficiency by 8.9-13.6%.

[0039] In summary, the cement grinding aid of this invention, used at 0.03-0.05% in the production of silicate cement, ordinary cement, slag cement, fly ash cement, pozzolanic cement, composite cement, and road cement, not only improves grinding efficiency but also reduces cement fineness, increases specific surface area, increases the content of 3-32μm cement particles, and reduces cement porosity, thereby altering the mineral structure and activity of cement and improving cement strength.

[0040] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0041] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A cement grinding aid, characterized in that, By weight, the raw materials include: 80-100 parts water, 15-20 parts hydrogen peroxide, and 0.5-2 parts sodium stannate.

2. The cement grinding aid as described in claim 1, characterized in that, The concentration of the hydrogen peroxide is 18%.

3. The cement grinding aid as described in claim 2, characterized in that, The cement grinding aid, by weight, comprises the following raw materials: 80 parts water, 20 parts hydrogen peroxide, and 0.5 parts sodium stannate.

4. The cement grinding aid as described in claim 2, characterized in that, The cement grinding aid, by weight, comprises the following raw materials: 90 parts water, 15 parts hydrogen peroxide, and 1.5 parts sodium stannate.

5. The cement grinding aid as described in claim 2, characterized in that, The cement grinding aid, by weight, comprises the following raw materials: 100 parts water, 18 parts hydrogen peroxide, and 2 parts sodium stannate.

6. The method for preparing the cement grinding aid according to any one of claims 1-5, characterized in that, step include: Hydrogen peroxide and water are mixed and stirred evenly, then sodium stannate is added, and the mixture is stirred and reacted to obtain the cement grinding aid.

7. The preparation method according to claim 6, characterized in that, The time for mixing until homogeneous is reached is 2 minutes.

8. The preparation method according to claim 6, characterized in that, The stirring reaction time is 2 minutes.

9. The application of the cement grinding aid according to any one of claims 1-5 in the preparation of cement products, characterized in that, The amount of cement grinding aid added in the preparation of cement products is 0.03-0.05 wt%.

10. The application as described in claim 9, characterized in that, The cement products include silicate cement, ordinary cement, slag cement, fly ash cement, pozzolanic cement, composite cement, or road cement.

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