Composite cement grinding aid and preparation method thereof
Through the synergistic effect of red mud-modified biochar and amine compounds, a composite cement grinding aid was prepared, which solved the problems of narrow applicability and unstable quality of existing grinding aids and achieved improvements in cement grinding efficiency and strength.
Patent Information
- Application Number
- CN202411027016.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-30
- Publication Date
- 2025-09-16
- Estimated Expiration
- 2044-07-30
AI Technical Summary
Existing cement grinding aids are mostly amines and alcohol compounds, which have relatively simple functional groups and a narrow range of applications, resulting in poor grinding aid effects and unstable quality in the market.
Red mud-modified biochar and alcoholamine compounds are used in a specific ratio to work synergistically to prepare a composite cement grinding aid. Red mud-modified biochar and alcoholamine compounds form stable chemical bonds, which enhances the grindability and hydration kinetics of the material and stimulates cement strength.
It significantly improves the grinding efficiency and strength of cement, reduces production costs, extends the service life of cement-based materials, and solves the quality instability problem of existing grinding aids.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of cement additives, and particularly relates to a composite cement grinding aid and a preparation method thereof. Background Art
[0002] Cement grinding aids can significantly reduce the electrostatic adsorption and balling phenomenon that occurs during the grinding process and reduce the tendency of ultrafine particles to reagglomerate during grinding. They also significantly improve cement fluidity, enhancing mill grinding performance and classifier efficiency. As a chemical additive, grinding aids also improve cement particle distribution and stimulate hydration dynamics, thereby increasing both early and late strength. Cement grinding aids have been widely used in the production lines of major cement plants, with their effectiveness increasing cement mill hourly output and cement strength at various ages.
[0003] There are many varieties of grinding aids, and their grinding aid effects vary greatly, which also have varying degrees of impact on cement performance. However, most of the current domestic grinding aids are alkanoic acid amines and alcohol compounds. However, the functional groups of single alkanoic acid amines and alcohol compounds are relatively simple, and the application range of materials is relatively narrow, which limits the grinding aid effect of the grinding aid. In addition, since the production process of cement grinding aids is relatively complicated and the manufacturing process level is uneven, there are many cement grinding aids with unstable quality on the market. The use of these low-quality products may cause the quality of building materials to decrease. Therefore, preparing a cement grinding aid with more stable quality and more excellent grinding aid enhancement performance has a wide range of market value and application prospects. Summary of the Invention
[0004] The present invention aims to provide a composite cement grinding aid. This material utilizes biochar modified from solid waste red mud and plant straw as raw materials. This improves the utilization of both solid waste red mud and plant straw, reducing production costs. Furthermore, the modified biochar and an alcoholamine compound, in a specific ratio, synergistically enhance the grindability of the material and increase cement hourly yield. Furthermore, the composite cement grinding aid improves cement particle distribution and stimulates hydration dynamics, thereby enhancing both early and late strength.
[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:
[0006] A composite cement grinding aid is prepared from the following raw materials in parts by weight: 30-40 parts of an alcoholamine compound, 10-15 parts of sodium sulfite, 20-30 parts of red mud-modified biochar, 5-10 parts of dilauryl thiodipropionate, 5-10 parts of sodium humate, 5-10 parts of molasses, and 30-40 parts of water.
[0007] Preferably, the alcoholamine compound is composed of monoethanol diisopropanolamine and diisopropyl monoethanolamine in a mass ratio of 2:1.
[0008] Preferably, the red mud modified biochar is prepared by the following method:
[0009] (1) Add red mud to deionized water and stir for 30 minutes to obtain a red mud suspension;
[0010] (2) Clean the plant straw and grind it into fine powder. Add the plant straw powder into the red mud suspension and continue stirring for 1 hour. Then filter it and dry the solid mixture in an oven to obtain a pretreated mixture.
[0011] (3) The pretreated mixture was placed in a nitrogen tubular furnace and heated to 750 °C at a set heating rate. The mixture was kept warm for 2 h under nitrogen protection and then naturally cooled to room temperature. The mixture was ground into fine powder and passed through a 40-mesh sieve to obtain red mud modified biochar.
[0012] Preferably, in step (1), the ratio of red mud to deionized water is 20 g:100 ml.
[0013] Preferably, the plant straw is corn straw or wheat straw.
[0014] Preferably, the ratio of the plant straw powder to the red mud suspension is 10g:100ml.
[0015] Preferably, in step (3), the heating rate of the nitrogen tubular furnace is 10°C / min to 350°C, and then 20°C / min to 750°C.
[0016] The present invention also provides a method for preparing the composite cement grinding aid, comprising the following steps:
[0017] S1: The alcoholamine compound is mixed in proportion, and then mixed with the red mud modified biochar, and stirred at a speed of 800 r / min for 15 minutes to obtain a uniformly dispersed mixture;
[0018] S2: Evenly mix the remaining materials with the mixture obtained in S1 to obtain a new composite cement grinding aid.
[0019] The raw materials used in the present invention are all commercially available.
[0020] The designed dosage of the grinding aid of the present invention is 0.05-0.08%.
[0021] Red mud, also known as bauxite residue, is an industrial byproduct of the aluminum oxide extraction process from bauxite. Due to the high cost of safe disposal, the current method for red mud disposal is mainly dry stacking, which results in significant waste of land resources and pollution. Therefore, comprehensive resource utilization of red mud is essential. Red mud itself has a unique oxide-rich structure (especially iron and aluminum oxides), surface hydroxyl groups and porosity. The biochar modified with red mud forms a stable chemical bond with the red mud, thereby increasing the porosity and specific surface area of the biochar, and enhancing the reaction activity and adsorption capacity of the biochar. It can be adsorbed on the surface of cement particles, enhancing the adsorption capacity of the material, preventing the spread of cracks, and improving the grindability of the material. At the same time, since red mud contains aluminum oxide and cement mineral component dicalcium silicate, dicalcium silicate has a seeding effect in the cement production process, which can improve the burnability of the raw material and reduce the burning temperature of the clinker. The amine compound used in the present invention can work together with the red mud-modified biochar to form a complex with iron and aluminum oxides, which can promote the hydration of C4AF to generate AFt, change the amount of Ca(OH)2 present in the cement stone hydration process, and thus accelerate the hydration of silicate minerals, stimulate the activity of cement materials, and thus increase the strength of cement.
[0022] The beneficial effects of the present invention are:
[0023] 1) The present invention uses red mud-modified biochar prepared by co-modifying solid waste red mud and plant straw as raw material, thereby improving the comprehensive utilization rate of solid waste and reducing the production cost of grinding aids. At the same time, the prepared red mud-modified biochar forms a stable chemical bond with the red mud, thereby increasing the porosity and specific surface area of the biochar, enhancing the reaction activity and adsorption capacity of the biochar, and being able to adsorb on the surface of cement particles, thereby enhancing the adsorption capacity of the material, preventing the spread of cracks, and improving the grindability of the material, which can significantly increase the hourly output of cement production.
[0024] 2) The red mud-modified biochar of the present invention has a synergistic effect with the alcoholamine compound, which can not only improve the grinding efficiency but also significantly increase the strength of cement and extend the service life of cement-based materials. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 The SEM comparison images of the biochar used in the present invention before and after modification with red mud, wherein a) is the biochar before modification, and b) is the biochar after modification with red mud; DETAILED DESCRIPTION
[0026] The technical solution of the present invention will be further described below with reference to specific embodiments, but is not limited thereto.
[0027] The red mud used in the present invention comes from the solid waste discharged from the Bayer process of alumina production in an aluminum plant in Shandong. Its specific chemical composition is shown in Table 1.
[0028] Table 1 Chemical composition of red mud
[0029]
[0030] Example 1
[0031] A composite cement grinding aid is prepared from the following raw materials in parts by weight: 30 parts of an alcoholamine compound, 10 parts of sodium sulfite, 20 parts of red mud-modified biochar, 5 parts of dilauryl thiodipropionate, 5 parts of sodium humate, 5 parts of molasses, and 30 parts of water.
[0032] The alcoholamine compound is composed of monoethanol diisopropanolamine and diisopropyl monoethanolamine in a mass ratio of 2:1.
[0033] The red mud modified biochar is prepared by the following method:
[0034] (1) Add red mud to deionized water and stir for 30 minutes to obtain a red mud suspension;
[0035] (2) Clean the plant straw and grind it into fine powder. Add the plant straw powder into the red mud suspension and continue stirring for 1 hour. Then filter it and dry the solid mixture in an oven to obtain a pretreated mixture.
[0036] (3) The pretreated mixture was placed in a nitrogen tubular furnace and heated to 750 °C at a set heating rate. The mixture was kept warm for 2 h under nitrogen protection and then naturally cooled to room temperature. The mixture was ground into fine powder and passed through a 40-mesh sieve to obtain red mud modified biochar.
[0037] In step (1), the ratio of red mud to deionized water is 20 g:100 ml.
[0038] The plant straw is corn straw or wheat straw.
[0039] The usage ratio of the plant straw powder to the red mud suspension is 10g:100ml.
[0040] In step (3), the heating rate of the nitrogen tubular furnace is 10°C / min to 350°C, and then 20°C / min to 750°C.
[0041] A method for preparing the composite cement grinding aid comprises the following steps:
[0042] S1: The alcoholamine compound is mixed in proportion, and then mixed with the red mud modified biochar, and stirred at a speed of 800 r / min for 15 minutes to obtain a uniformly dispersed mixture;
[0043] S2: Evenly mix the remaining materials with the mixture obtained in S1 to obtain a new composite cement grinding aid.
[0044] Example 2
[0045] A composite cement grinding aid is prepared from the following raw materials in parts by weight: 40 parts of an alcoholamine compound, 15 parts of sodium sulfite, 30 parts of red mud-modified biochar, 10 parts of dilauryl thiodipropionate, 10 parts of sodium humate, 10 parts of molasses, and 40 parts of water.
[0046] The alcoholamine compound is composed of monoethanol diisopropanolamine and diisopropyl monoethanolamine in a mass ratio of 2:1.
[0047] The red mud modified biochar is prepared by the following method:
[0048] (1) Add red mud to deionized water and stir for 30 minutes to obtain a red mud suspension;
[0049] (2) Clean the plant straw and grind it into fine powder. Add the plant straw powder into the red mud suspension and continue stirring for 1 hour. Then filter it and dry the solid mixture in an oven to obtain a pretreated mixture.
[0050] (3) The pretreated mixture was placed in a nitrogen tubular furnace and heated to 750 °C at a set heating rate. The mixture was kept warm for 2 h under nitrogen protection and then naturally cooled to room temperature. The mixture was ground into fine powder and passed through a 40-mesh sieve to obtain red mud modified biochar.
[0051] In step (1), the ratio of red mud to deionized water is 20 g:100 ml.
[0052] The plant straw is corn straw or wheat straw.
[0053] The usage ratio of the plant straw powder to the red mud suspension is 10g:100ml.
[0054] In step (3), the heating rate of the nitrogen tubular furnace is 10°C / min to 350°C, and then 20°C / min to 750°C.
[0055] A method for preparing the composite cement grinding aid comprises the following steps:
[0056] S1: The alcoholamine compound is mixed in proportion, and then mixed with the red mud modified biochar, and stirred at a speed of 800 r / min for 15 minutes to obtain a uniformly dispersed mixture;
[0057] S2: Evenly mix the remaining materials with the mixture obtained in S1 to obtain a new composite cement grinding aid.
[0058] Example 3
[0059] A composite cement grinding aid is prepared from the following raw materials in parts by weight: 35 parts of an alcoholamine compound, 12 parts of sodium sulfite, 25 parts of red mud-modified biochar, 8 parts of dilauryl thiodipropionate, 8 parts of sodium humate, 7 parts of molasses, and 35 parts of water.
[0060] The alcoholamine compound is composed of monoethanol diisopropanolamine and diisopropyl monoethanolamine in a mass ratio of 2:1.
[0061] The red mud modified biochar is prepared by the following method:
[0062] (1) Add red mud to deionized water and stir for 30 minutes to obtain a red mud suspension;
[0063] (2) Clean the plant straw and grind it into fine powder. Add the plant straw powder into the red mud suspension and continue stirring for 1 hour. Then filter it and dry the solid mixture in an oven to obtain a pretreated mixture.
[0064] (3) The pretreated mixture was placed in a nitrogen tubular furnace and heated to 750 °C at a set heating rate. The mixture was kept warm for 2 h under nitrogen protection and then naturally cooled to room temperature. The mixture was ground into fine powder and passed through a 40-mesh sieve to obtain red mud modified biochar.
[0065] In step (1), the ratio of red mud to deionized water is 20 g:100 ml.
[0066] The plant straw is corn straw or wheat straw.
[0067] The usage ratio of the plant straw powder to the red mud suspension is 10g:100ml.
[0068] In step (3), the heating rate of the nitrogen tubular furnace is 10°C / min to 350°C, and then 20°C / min to 750°C.
[0069] A method for preparing the composite cement grinding aid comprises the following steps:
[0070] S1: The alcoholamine compound is mixed in proportion, and then mixed with the red mud modified biochar, and stirred at a speed of 800 r / min for 15 minutes to obtain a uniformly dispersed mixture;
[0071] S2: Evenly mix the remaining materials with the mixture obtained in S1 to obtain a new composite cement grinding aid.
[0072] Comparative Example 1
[0073] A composite cement grinding aid is made from the following raw materials in parts by weight: A new composite cement grinding aid is made from the following raw materials in parts by weight: 35 parts of an alcoholamine compound, 12 parts of sodium sulfite, 25 parts of red mud, 8 parts of dilauryl thiodipropionate, 8 parts of sodium humate, 7 parts of molasses, and 35 parts of water.
[0074] The alcoholamine compound is composed of monoethanol diisopropanolamine and diisopropyl monoethanolamine in a mass ratio of 2:1.
[0075] A method for preparing the composite cement grinding aid comprises the following steps:
[0076] S1: Mix the alcoholamine compound in proportion, then mix it with red mud, and stir it at a speed of 800 r / min for 15 minutes to obtain a uniformly dispersed mixture;
[0077] S2: Evenly mix the remaining materials with the mixture obtained in S1 to obtain a new composite cement grinding aid.
[0078] The above comparative example 1 is basically the same as example 3, except that the red mud used is unmodified red mud.
[0079] Comparative Example 2
[0080] A composite cement grinding aid is prepared from the following raw materials in parts by weight: 35 parts of an alcoholamine compound, 12 parts of sodium sulfite, 25 parts of biochar, 8 parts of dilauryl thiodipropionate, 8 parts of sodium humate, 7 parts of molasses, and 35 parts of water.
[0081] The alcoholamine compound is composed of monoethanol diisopropanolamine and diisopropyl monoethanolamine in a mass ratio of 2:1.
[0082] The biochar is prepared by the following method: cleaning plant straw and grinding it into fine powder, then placing the plant straw powder in a nitrogen tubular furnace and setting the heating rate to 750° C., keeping the temperature under nitrogen protection for 2 hours, then naturally cooling to room temperature and grinding it into fine powder, and passing it through a 40-mesh sieve to obtain the biochar.
[0083] The plant straw is corn straw or wheat straw; the heating rate of the nitrogen tubular furnace is 10°C / min to 350°C, and then 20°C / min to 750°C.
[0084] A method for preparing the composite cement grinding aid comprises the following steps:
[0085] S1: The alcoholamine compound is mixed in proportion, then mixed with biochar, and stirred at a speed of 800 r / min for 15 minutes to obtain a uniformly dispersed mixture;
[0086] S2: Evenly mix the remaining materials with the mixture obtained in S1 to obtain a new composite cement grinding aid.
[0087] The above comparative example is basically the same as Example 3, except that the biochar used is unmodified biochar.
[0088] Comparative Example 3
[0089] A composite cement grinding aid is prepared from the following raw materials in parts by weight: 35 parts of an alcoholamine compound, 12 parts of sodium sulfite, 25 parts of red mud-modified biochar, 8 parts of dilauryl thiodipropionate, 8 parts of sodium humate, 7 parts of molasses, and 35 parts of water.
[0090] The alcoholamine compound is triethanolamine.
[0091] The red mud modified biochar is prepared by the following method:
[0092] (1) Add red mud to deionized water and stir for 30 minutes to obtain a red mud suspension;
[0093] (2) Clean the plant straw and grind it into fine powder. Add the plant straw powder into the red mud suspension and continue stirring for 1 hour. Then filter it and dry the solid mixture in an oven to obtain a pretreated mixture.
[0094] (3) The pretreated mixture was placed in a nitrogen tubular furnace and heated to 750 °C at a set heating rate. The mixture was kept warm for 2 h under nitrogen protection and then naturally cooled to room temperature. The mixture was ground into fine powder and passed through a 40-mesh sieve to obtain red mud modified biochar.
[0095] In step (1), the ratio of red mud to deionized water is 20 g:100 ml.
[0096] The plant straw is corn straw or wheat straw.
[0097] The usage ratio of the plant straw powder to the red mud suspension is 10g:100ml.
[0098] In step (3), the heating rate of the nitrogen tubular furnace is 10°C / min to 350°C, and then 20°C / min to 750°C.
[0099] A method for preparing the composite cement grinding aid comprises the following steps:
[0100] S1: The alcoholamine compound is mixed in proportion, and then mixed with the red mud modified biochar, and stirred at a speed of 800 r / min for 15 minutes to obtain a uniformly dispersed mixture;
[0101] S2: Evenly mix the remaining materials with the mixture obtained in S1 to obtain a new composite cement grinding aid.
[0102] The comparative example is substantially the same as Example 3, except that the alcoholamine compound used is triethanolamine.
[0103] Comparative Example 4
[0104] A composite cement grinding aid is prepared from the following raw materials in parts by weight: 35 parts of an alcoholamine compound, 12 parts of sodium sulfite, 25 parts of red mud-modified biochar, 8 parts of dilauryl thiodipropionate, 8 parts of sodium humate, 7 parts of molasses, and 35 parts of water.
[0105] The alcoholamine compound is triisopropanolamine.
[0106] The red mud modified biochar is prepared by the following method:
[0107] (1) Add red mud to deionized water and stir for 30 minutes to obtain a red mud suspension;
[0108] (2) Clean the plant straw and grind it into fine powder. Add the plant straw powder into the red mud suspension and continue stirring for 1 hour. Then filter it and dry the solid mixture in an oven to obtain a pretreated mixture.
[0109] (3) The pretreated mixture was placed in a nitrogen tubular furnace and heated to 750 °C at a set heating rate. The mixture was kept warm for 2 h under nitrogen protection and then naturally cooled to room temperature. The mixture was ground into fine powder and passed through a 40-mesh sieve to obtain red mud modified biochar.
[0110] In step (1), the ratio of red mud to deionized water is 20 g:100 ml.
[0111] The plant straw is corn straw or wheat straw.
[0112] The usage ratio of the plant straw powder to the red mud suspension is 10g:100ml.
[0113] In step (3), the heating rate of the nitrogen tubular furnace is 10°C / min to 350°C, and then 20°C / min to 750°C.
[0114] A method for preparing the composite cement grinding aid comprises the following steps:
[0115] S1: The alcoholamine compound is mixed in proportion, and then mixed with the red mud modified biochar, and stirred at a speed of 800 r / min for 15 minutes to obtain a uniformly dispersed mixture;
[0116] S2: Evenly mix the remaining materials with the mixture obtained in S1 to obtain a new composite cement grinding aid.
[0117] The comparative example is substantially the same as Example 3, except that the alcoholamine compound used is triisopropanolamine.
[0118] Comparative Example 5
[0119] A composite cement grinding aid, whose raw material composition and preparation method are basically the same as those in Example 3, except that the alcoholamine compound is composed of monoethanol diisopropanolamine and diisopropyl monoethanolamine in a mass ratio of 1:2.
[0120] Comparative Example 6
[0121] A composite cement grinding aid, whose raw material composition and preparation method are basically the same as those in Example 3, except that the alcoholamine compound is composed of monoethanol diisopropanolamine and diisopropyl monoethanolamine in a mass ratio of 1:1.
[0122] Comparative Example 7
[0123] A composite cement grinding aid, whose raw material composition and preparation method are basically the same as those in Example 3, except that the alcoholamine compound is composed of monoethanol diisopropanolamine and diisopropyl monoethanolamine in a mass ratio of 3:1.
[0124] Comparative Example 8
[0125] A composite cement grinding aid, whose raw material composition and preparation method are basically the same as those in Example 3, except that the alcoholamine compound is monoethanoldiisopropanolamine.
[0126] Comparative Example 9
[0127] A composite cement grinding aid, whose raw material composition and preparation method are basically the same as those in Example 3, except that the alcoholamine compound is diisopropyl monoethanolamine.
[0128] Performance Testing
[0129] To further illustrate the effectiveness of the grinding aid of the present invention, Examples 1-3 and Comparative Examples 1-7 were added to cement raw materials at a dosage of 0.05 wt%. A blank control group (i.e., no grinding aid) was also prepared. The various properties of the samples were statistically analyzed and compared. The cement raw material ratio was: 68 wt% clinker, 5 wt% gypsum, and 27 wt% slag. The cement was ground in a 5370 mm diameter vertical mill for 30 minutes. The sieve residue, setting time, and strength were tested according to GB / T 1345-2005, "Determination of Cement Fineness by Sieve Analysis." The standard consistency water requirement, stability, and setting time of the cement were determined according to GB / T 1346-2001, "Water Requirement, Stability, and Setting Time of Cement." The strength of the cement mortar was determined according to GB / T 17671-1999, "Test Method for Cement Mortar Strength (ISO Method)." The test results are shown in Table 1 below.
[0130] Table 1 Performance test results
[0131]
[0132] It can be seen from the data in Table 1 that, for the composite cement grinding aids prepared in Examples 1-3 of the present invention, the 3-day / 28-day flexural and compressive strengths of the cements with different cement grinding aids added are improved to varying degrees compared with the blank examples within the same grinding time, with the 45 μm sieve residue significantly reduced. The average hourly output is 202.7 t / h, the average 28-day compressive strength is 59.4 MPa, and the average 28-day flexural strength is 8.2 MPa. From the data of comparative examples 1-2, it can be seen that compared with the blank example, the comparative example 1 using red mud alone increases the output by 10 t / h and the compressive strength at 28 days by 2.1 MPa; the comparative example 2 using biochar alone increases the output by 13 t / h and the compressive strength at 28 days by 1.7 MPa; and the average values of Examples 1-3 of the present invention increase the output by 37.7 t / h and the compressive strength at 28 days by 9.2 MPa compared with the blank, which are significantly greater than those of comparative example 1, comparative example 2 or the combination of the two. This shows that the biochar modified with red mud in the present invention forms a stable chemical bond with the red mud, and the red mud is stably adsorbed on the surface of the biochar (such as Figure 1As shown), the two substances act synergistically to improve the porosity and specific surface area of the modified biochar, enhance the reactivity and adsorption capacity of the biochar, can be adsorbed on the surface of cement particles, enhance the adsorption capacity of the material, prevent the spread of cracks, and improve the grindability of the material. At the same time, since red mud contains aluminum oxide and cement mineral component dicalcium silicate, dicalcium silicate has a seeding effect in the cement production process, which can improve the burnability of the raw material and reduce the burning temperature of the clinker. In addition, it can be seen from the data comparison of Comparative Examples 5-9 that the alcoholamine compound used in the present invention can work together with the red mud modified biochar to form a complex with iron and aluminum oxides, which can promote the hydration of C4AF to generate AFt, change the amount of Ca(OH)2 in the cement stone hydration process, thereby accelerating the hydration of silicate minerals, stimulating the activity of cement materials, and thus increasing the strength of cement; changing the composition or dosage ratio of the alcoholamine compound cannot achieve the best use effect.
[0133] It should be noted that the above embodiments are only some of the preferred embodiments of the present invention, and not all of them. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.
Claims
1. A composite cement grinding aid, characterized in that: The invention is prepared from the following raw materials in parts by weight: 30-40 parts of alcoholamine compounds, 10-15 parts of sodium sulfite, 20-30 parts of red mud modified biochar, 5-10 parts of dilauryl thiodipropionate, 5-10 parts of sodium humate, 5-10 parts of molasses and 30-40 parts of water.
2. The composite cement grinding aid according to claim 1, wherein The alcoholamine compound is composed of monoethanol diisopropanolamine and diisopropyl monoethanolamine in a mass ratio of 2:
1.
3. The composite cement grinding aid according to claim 1, characterized in that The red mud modified biochar is prepared by the following method: (1) Add red mud to deionized water and stir for 30 minutes to obtain a red mud suspension; (2) Clean the plant straw and grind it into fine powder. Add the plant straw powder into the red mud suspension and continue stirring for 1 hour. Then filter it and dry the solid mixture in an oven to obtain a pretreated mixture. (3) The pretreated mixture was placed in a nitrogen tubular furnace and heated to 750 °C at a set heating rate. The mixture was kept warm for 2 h under nitrogen protection, then naturally cooled to room temperature, ground into fine powder, and passed through a 40-mesh sieve to obtain red mud-modified biochar.
4. The composite cement grinding aid according to claim 3, wherein In step (1), the ratio of red mud to deionized water is 20 g:100 ml.
5. The composite cement grinding aid according to claim 3, characterized in that The plant straw is corn straw or wheat straw.
6. The composite cement grinding aid according to claim 3, characterized in that The usage ratio of the plant straw powder to the red mud suspension is 10g:100ml.
7. The composite cement grinding aid according to claim 3, characterized in that In step (3), the heating rate of the nitrogen tubular furnace is 10°C / min to 350°C, and then 20°C / min to 750°C.
8. A method for preparing the composite cement grinding aid according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: The alcoholamine compound is mixed in proportion, and then mixed with the red mud modified biochar, and stirred at a speed of 800 r / min for 15 minutes to obtain a uniformly dispersed mixture; S2: Evenly mix the remaining materials with the mixture obtained in S1 to obtain a composite cement grinding aid.
Citation Information
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