A kind of powder grinding aid and preparation method thereof

Abstract

The present application relates to the field of cement grinding aids, and specifically discloses a powder grinding aid and a preparation method thereof. A powder grinding aid is prepared by mixing and drying the following raw materials in parts by weight: 30-50 parts of rice husk ash, 5-10 parts of modified triethanolamine, 3-5 parts of triisopropanolamine, 5-8 parts of water, and 2-3 parts of calcium lignin sulfonate; wherein the particle size of the rice husk ash is 1-2 microns. The grinding aid prepared in the present application has the advantages of good grinding aid performance and can improve the early and late compressive strength of cement.

Description

Technical Field

[0001] The present application relates to the field of cement grinding aids, and more specifically, to a powder grinding aid and a preparation method thereof. Background Art

[0002] In the cement production process, it is usually necessary to grind the cement raw materials. During the grinding process, cement grinding aids are added to the cement raw materials. Cement grinding aids are substances that can adsorb on the surface of cement particles, reduce the attraction between cement particles, and at the same time improve the fluidity of grinding, thereby significantly improving grinding efficiency.

[0003] Although cement grinding aids currently on the market can effectively improve the grinding efficiency of cement particles, the produced cement particles still have uneven particle sizes, resulting in insufficient hydration reaction and low hydration reaction rate, resulting in low strength of cement products. Summary of the invention

[0004] In order to improve the grinding effect of the grinding aid and increase the strength of cement, the present application provides a powder grinding aid and a preparation method thereof.

[0005] In the first aspect, the present application provides a powder grinding aid, which adopts the following technical solution:

[0006] A powder grinding aid is prepared by mixing and drying the following raw materials in parts by weight: 30-50 parts of rice husk ash, 5-10 parts of modified triethanolamine, 3-5 parts of triisopropanolamine, 5-8 parts of water and 2-3 parts of calcium lignin sulfonate; wherein the particle size of the rice husk ash is 1-2 microns.

[0007] By adopting the above technical solution, the present application adopts rice husk ash as a grinding aid. Rice husk ash has good adsorption properties and can be adsorbed on cement particles to improve the dispersibility between cement particles, which is beneficial to cement grinding. In addition, during the cement mixing process, rice husk ash contains a large amount of amorphous silicon dioxide. Silicon dioxide reacts with calcium hydroxide generated by hydration reaction to form CSH gel, thereby improving the strength of cement products. The porous structure of rice husk ash is conducive to the adsorption of water by volcanic ash reaction, thereby improving the strength of cement products.

[0008] The present application adopts modified triethanolamine, triisopropanolamine and rice husk ash to premix into liquid, and a part of the alcoholamine molecules can be adsorbed on the surface of rice husk ash, which can improve the dispersibility of rice husk ash and further improve the grinding aid effect of the grinding aid. On the other hand, the modified triethanolamine, triisopropanolamine and rice husk ash are adsorbed on the surface of cement particles together. In the process of grinding cement, the alcoholamine molecules are continuously rubbed and collided with the cement particles, so that the alcoholamine molecules are attached to the surface of the cement particles to form a monomolecular adsorption film to play a role in lubrication and grinding of cement particles. In addition, the modified triethanolamine can promote the development of early strength of cement, and the triisopropanolamine can promote the development of late strength of cement. The grinding aid prepared by the joint action of rice husk ash, modified triethanolamine and triisopropanolamine has better grinding aid performance and can effectively improve the strength of cement.

[0009] Calcium lignin sulfonate molecules contain polar functional groups such as carboxyl and phenolic hydroxyl groups, which can be adsorbed on the surface of cement clinker. Calcium lignin sulfonate molecules are first adsorbed on the high-energy surface of the material to reduce the energy density and the strength of the particle fracture surface. As the particle cracks continue to expand, the calcium lignin sulfonate molecules further penetrate into the cracks to prevent the powder cracks from closing again. It can also promote substances such as alcoholamine molecules to enter the gaps between cement particles, thereby increasing the grinding efficiency and further improving the strength of cement.

[0010] Preferably, the modified triethanolamine comprises the following preparation steps:

[0011] Triethanolamine and glacial acetic acid are stirred and mixed, and concentrated sulfuric acid as a catalyst is added dropwise before heating, and then the temperature is raised to 130-140° C. and refluxed. After the reaction is completed, the temperature is lowered to obtain modified triethanolamine, wherein the mass ratio of triethanolamine to glacial acetic acid is (3-5):1.

[0012] By adopting the above technical solution, after the triethanolamine is modified, it is conducive to its adsorption to the cement surface, and continuously penetrates into the micro cracks of solid particles, producing a "wedge splitting effect" on these cracks. This continuous penetration and "wedge splitting effect" can expand old cracks and continuously generate new micro cracks, reducing the external force required for fracture, greatly accelerating the expansion speed of cracks, and making it easier to be ground into particles with smaller particle sizes to further improve the grinding aid performance.

[0013] Preferably, the mass ratio of the rice husk ash, modified triethanolamine and triisopropanolamine is 10:1:1.

[0014] By adopting the above technical scheme, when the mass ratio of rice husk ash, modified triethanolamine and triisopropanolamine is 10:1:1, their synergistic effect can be fully exerted to further improve the grinding performance of the grinding aid and the mechanical properties of cement.

[0015] Preferably, 3-5 parts by weight of an auxiliary agent is further added, wherein the auxiliary agent includes p-aminophenol and sodium thiocyanate.

[0016] By adopting the above technical scheme, the combined effect of amine molecules and p-aminophenol can improve the particle fineness of cement powder. At the same time, it can also increase the strength of cement and significantly improve the later strength of cement. Sodium thiocyanate is added to the grinding aid. The combination of sodium thiocyanate and aminophenol can improve the early strength and later strength of cement.

[0017] Preferably, the mass ratio of p-aminophenol to sodium thiocyanate is (2-3):1.

[0018] By adopting the above technical solution, when the mass ratio of p-aminophenol to sodium thiocyanate is (2-3):1, the grinding aid performance of the grinding aid and the mechanical properties of cement can be further improved.

[0019] Preferably, 10-20 parts by weight of fly ash are also added.

[0020] By adopting the above technical solution, fly ash is a spherical powder material, which is combined with rice husk ash to optimize the particle size distribution of the powder grinding aid and improve the grinding efficiency of the grinding aid.

[0021] Preferably, the mass ratio of rice husk ash to fly ash is (3-5):1.

[0022] By adopting the above technical solution, when the mass ratio of rice husk ash to fly ash is (3-5):1, the grinding aid performance of the grinding aid and the mechanical properties of cement can be further improved.

[0023] In a second aspect, the present application provides a method for preparing a powder grinding aid, using the following technical solution:

[0024] The following steps are involved:

[0025] S1: adding modified triethanolamine and triisopropanolamine into water to prepare liquid alcoholamine;

[0026] S2: Mix liquid alcoholamine, rice husk ash and calcium lignin sulfonate, stir evenly and then dry to obtain a powder grinding aid.

[0027] In summary, this application has the following beneficial effects:

[0028] 1. The present application uses rice husk ash as a grinding aid. Rice husk ash has good adsorption properties and can be adsorbed on cement particles to improve the dispersibility between cement particles, which is beneficial to cement grinding. In addition, during the cement mixing process, rice husk ash contains a large amount of amorphous silicon dioxide. Silicon dioxide reacts with calcium hydroxide generated by hydration reaction to form CSH gel, thereby improving the strength of cement products. The porous structure of rice husk ash is conducive to the adsorption of water by volcanic ash reaction, thereby improving the strength of cement products.

[0029] 2. The present application adopts modified triethanolamine, triisopropanolamine and rice husk ash to premix into liquid, and a part of the alcoholamine molecules can be adsorbed on the surface of rice husk ash, which can improve the dispersibility of rice husk ash and further improve the grinding aid effect of the grinding aid. On the other hand, the modified triethanolamine, triisopropanolamine and rice husk ash are adsorbed on the surface of cement particles together. In the process of grinding cement, the alcoholamine molecules are continuously rubbed and collided with cement particles, so that the alcoholamine molecules are attached to the surface of cement particles to form a monomolecular adsorption film to play a role in lubrication and grinding of cement particles. In addition, the modified triethanolamine can promote the development of early strength of cement, and the triisopropanolamine can promote the development of late strength of cement. The grinding aid prepared by the joint action of rice husk ash, modified triethanolamine and triisopropanolamine has better grinding aid performance and can effectively improve the strength of cement.

[0030] 3. The combined action of amine molecules and p-aminophenol can improve the particle fineness of cement powder. At the same time, it can also increase the strength of cement and significantly improve the later strength of cement. Adding sodium thiocyanate to the grinding aid, sodium thiocyanate and aminophenol can improve the early and later strength of cement. DETAILED DESCRIPTION

[0031] Source of raw materials

[0032] Rice husk ash was from Shanghai Hongjun Horticultural Products Co., Ltd.;

[0033] Triethanolamine was from Tianjin Fuyu Fine Chemical Co., Ltd.;

[0034] Triisopropanolamine was from Shijiazhuang Haisen Chemical Co., Ltd.;

[0035] Calcium lignin sulfonate was from Shandong Kaishengde Chemical Co., Ltd.;

[0036] p-Aminophenol was from Shandong Jiaying Chemical Technology Co., Ltd.;

[0037] Sodium thiocyanate was from Shandong Maofa Chemical Co., Ltd.;

[0038] The fly ash comes from Lingshou County Dongbang Mineral Powder Factory, item number 29.

[0039] The present application is further described in detail below in conjunction with preparation examples and embodiments.

[0040] Preparation Example

[0041] Preparation Example 1

[0042] Preparation of modified triethanolamine:

[0043] 3 kg of triethanolamine and 1 kg of glacial acetic acid were stirred and mixed, and 2 drops of concentrated sulfuric acid were added, and then the temperature was raised to 130°C and refluxed. After reacting for 4 hours, the temperature was lowered to obtain modified triethanolamine.

[0044] Preparation Example 2

[0045] Preparation of modified triethanolamine:

[0046] 4 kg of triethanolamine and 1 kg of glacial acetic acid were stirred and mixed, and 2 drops of concentrated sulfuric acid were added. The mixture was then heated to 135°C and refluxed. After reacting for 4.5 hours, the mixture was cooled to obtain modified triethanolamine.

[0047] Preparation Example 3

[0048] Preparation of modified triethanolamine:

[0049] 5 kg of triethanolamine and 1 kg of glacial acetic acid were stirred and mixed, and 2 drops of concentrated sulfuric acid were added, and then the temperature was raised to 140°C and refluxed. After reacting for 5 hours, the temperature was lowered to obtain modified triethanolamine.

[0050] Example

[0051] Example 1

[0052] A method for preparing a powder grinding aid comprises the following steps:

[0053] S1: Add 5 kg of modified triethanolamine and 3 kg of triisopropanolamine into 5 kg of water to prepare liquid alcoholamine;

[0054] S2: Mix liquid alcohol amine, 30kg rice husk ash, 3kg calcium lignin sulfonate, 3kg additives (2kg p-aminophenol, 1kg sodium thiocyanate) and 10kg fly ash, stir evenly and dry to obtain a powder grinding aid; the particle size of the rice husk ash is 1-2 microns, and the modified triethanolamine comes from Preparation Example 1.

[0055] Example 2

[0056] A method for preparing a powder grinding aid comprises the following steps:

[0057] S1: Add 7 kg of modified triethanolamine and 4 kg of triisopropanolamine into 6 kg of water to prepare liquid alcoholamine;

[0058] S2: Mix liquid alcohol amine, 40kg rice husk ash, 2kg calcium lignin sulfonate, 4kg additives (2kg p-aminophenol, 2kg sodium thiocyanate) and 15kg fly ash, stir evenly and dry to obtain a powder grinding aid; the particle size of the rice husk ash is 1-2 microns, and the modified triethanolamine comes from Preparation Example 1.

[0059] Example 3

[0060] A method for preparing a powder grinding aid comprises the following steps:

[0061] S1: Add 10 kg of modified triethanolamine and 5 kg of triisopropanolamine into 8 kg of water to prepare liquid alcoholamine;

[0062] S2: Mix liquid alcohol amine, 50 kg rice husk ash, 2.5 kg calcium lignin sulfonate, 5 kg additives (3 kg p-aminophenol, 2 kg sodium thiocyanate) and 20 kg fly ash, stir evenly and dry to obtain a powder grinding aid; wherein the particle size of the rice husk ash is 1-2 microns, and the modified triethanolamine comes from Preparation Example 1.

[0063] Example 4

[0064] The difference between Example 4 and Example 2 is that the modified triethanolamine comes from Preparation Example 2, and the remaining steps are the same as Example 2.

[0065] Example 5

[0066] The difference between Example 5 and Example 2 is that the modified triethanolamine comes from Preparation Example 3, and the remaining steps are the same as Example 2.

[0067] Embodiment 6-10

[0068] The difference between Example 6-10 and Example 2 is that the masses and mass ratios of rice husk ash, modified triethanolamine and triisopropanolamine are different. The masses of rice husk ash, modified triethanolamine and triisopropanolamine are shown in the following table:

[0069] Table 1 Mass of rice husk ash, modified triethanolamine and triisopropanolamine in Examples 6-10

[0070] Rice husk ash / kg Modified triethanolamine / kg Triisopropanolamine / kg Example 6 30 5 3 Example 7 50 10 5 Example 8 28 4 2 Example 9 51 11 6 Example 10 50 5 5

[0071] Embodiment 11

[0072] The difference between Example 11 and Example 10 is that no auxiliary agent is added, and the remaining steps are the same as Example 10.

[0073] Example 12

[0074] The difference between Example 12 and Example 10 is that p-aminophenol is not added, and the remaining steps are the same as Example 10.

[0075] Example 13

[0076] The difference between Example 13 and Example 10 is that sodium thiocyanate is not added, and the remaining steps are the same as Example 10.

[0077] Examples 14-18

[0078] The difference between Examples 14-18 and Example 10 is that the masses and mass ratios of p-aminophenol and sodium thiocyanate are different. The masses of p-aminophenol and sodium thiocyanate in Examples 14-18 are shown in the following table:

[0079] Table 2 The mass of p-aminophenol and sodium thiocyanate and the mass ratio of p-aminophenol and sodium thiocyanate in Examples 14-18

[0080]

[0081]

[0082] Embodiment 19

[0083] The difference between Example 19 and Example 15 is that fly ash is replaced by silica ash, and the remaining steps are the same as Example 15.

[0084] Embodiment 20

[0085] The difference between Example 20 and Example 15 is that fly ash is not added, and the remaining steps are the same as Example 15.

[0086] Examples 21-24

[0087] The difference between Examples 21-24 and Example 15 is that the mass of fly ash is different. The mass of fly ash in Example 15 is 15 kg, and the mass ratio of rice husk ash to fly ash is 3.3:1. The mass of fly ash and the mass ratio of fly ash to rice husk ash in Examples 21-24 are shown in the following table:

[0088] Table 2 The mass of rice husk ash and fly ash and the mass ratio of rice husk ash to fly ash in Examples 21-24

[0089] Fly ash / kg Rice husk ash / kg The quality ratio of the two Embodiment 21 10 50 5：1 Embodiment 22 20 50 2.5：1 Embodiment 23 16.7 50 3：1 Embodiment 24 8 50 6.2：1

[0090] Comparative Example

[0091] Comparative Example 1

[0092] The difference between Comparative Example 1 and Example 15 is that no water is added, and the remaining steps are the same as Example 15.

[0093] Comparative Example 2

[0094] The difference between Comparative Example 2 and Example 15 is that the triethanolamine is not modified, and the remaining steps are the same as Example 15.

[0095] Comparative Example 3

[0096] The difference between Comparative Example 3 and Example 15 is that modified triethanolamine and triisopropanolamine are not added, and the remaining steps are the same as those of Example 15.

[0097] Comparative Example 4

[0098] The difference between Comparative Example 4 and Example 15 is that modified triethanolamine is replaced by ethylene glycol, and triisopropanolamine is replaced by propylene glycol, and the remaining steps are the same as those of Example 15.

[0099] Comparative Example 5

[0100] The difference between Comparative Example 5 and Example 15 is that rice husk ash is not added, and the remaining steps are the same as those of Example 15.

[0101] Comparative Example 6

[0102] The difference between Comparative Example 6 and Example 15 is that rice husk ash is replaced with silica ash, and the remaining steps are the same as those of Example 15.

[0103] Performance testing

[0104] Detection Methods

[0105] The cement grinding aids prepared in Examples 1-24 and Comparative Examples 1-6 were added to the cement raw materials and mixed evenly, and then ground in a ball mill for 1 hour. The specific surface area and fineness (0.045 sieve residue) of the cement before and after grinding were measured;

[0106] The cement obtained by grinding under the same grinding conditions as above was mixed with water, with the amount of cement being 250 parts, the amount of mixing water being 30 parts, and the amount of grinding aid being 1 part, and then poured into a mold for casting, and then steam-cured to obtain a cement product. The 7-day compressive strength and 28-day compressive strength of the cement product were tested according to GB / T17671-1999.

[0107] When no grinding aid is added, the 45-micron sieve residue (%) of the cement is 11.3%, the specific surface area is 288 (m2 / kg), the 7-day compressive strength is 15.5 MPa, and the 28-day compressive strength is 28.3 MPa.

[0108] The following table shows the properties of the grinding aids prepared in Examples 1-24 and Comparative Examples 1-6 and the effects of adding them to cement on the mechanical properties of cement.

[0109] Table 4 Performance of grinding aids prepared in Examples 1-24 and Comparative Examples 1-6 and their effects on cement compressive strength

[0110]

[0111]

[0112] Combining Examples 1-3 and Table 4, it can be seen that after adding the grinding aid prepared in the present application, the fineness and specific surface area of ​​the cement after grinding are significantly increased, and the early and late strength of the cement can be significantly improved when added to the cement. Compared with Examples 1 and 3, the grinding aid prepared in Example 2 is added to the cement, and the cement particles are finer, the specific surface area is larger, and the early and late strength of the cement is greater.

[0113] Combining the data of Example 2, Examples 4-5 and Table 4, it can be seen that the grinding aid prepared in Preparation Example 1 has better performance. After being added to cement and ground, the cement particles are finer, the specific surface area is larger, and the early and late strengths of the cement are greater.

[0114] Combining the data of Example 2, Examples 6-10 and Table 4, it can be seen that after the grinding aid prepared in Example 10 is added to cement, the cement particles are finer, the specific surface area is larger, and the early and late strengths of the cement are greater. That is, when the mass ratio of rice husk ash, modified triethanolamine and triisopropanolamine is 10:1:1, their synergistic effect can be fully exerted, and the grinding aid performance of the grinding aid and the mechanical properties of the cement are further improved.

[0115] It can be seen from the data of Example 10, Examples 11-13 and Table 4 that the use of aminophenol and sodium thiocyanate together can significantly improve the grinding aid performance of the grinding aid and the mechanical strength of cement. This is mainly because the amine molecules and p-aminophenol can work together to improve the particle fineness of cement powder. At the same time, the cement strength can also be increased and the late strength of cement can be significantly improved. Adding sodium thiocyanate to the grinding aid and sodium thiocyanate and aminophenol can improve the early strength and late strength of cement.

[0116] Combining the data of Example 10, Examples 14-18 and Table 4, it can be seen that when the mass ratio of p-aminophenol to sodium thiocyanate is (2-3):1, the grinding aid performance of the grinding aid and the mechanical properties of the cement can be further improved.

[0117] Combining the data of Example 15, Examples 19-20 and Table 4, it can be seen that adding fly ash to the grinding aid and the cooperation between fly ash and rice husk ash can significantly improve the grinding performance of the grinding aid, thereby improving the fineness and compressive strength of cement.

[0118] Combining the data of Example 15, Examples 21-24 and Table 4, it can be seen that when the mass ratio of rice husk ash to fly ash is (3-5):1, the grinding aid performance of the grinding aid and the mechanical properties of cement can be further improved.

[0119] Combining the data of Example 15, Comparative Example 1 and Table 4, it can be seen that the modified triethanolamine and triisopropanolamine are mixed with water and then mixed with rice husk ash, which is beneficial to improve the grinding aid performance of the grinding aid, thereby improving the mechanical properties of cement. This is mainly because the modified triethanolamine and triisopropanolamine are mixed with water and then mixed with rice husk ash, which is beneficial to the adsorption of alcoholamine molecules on rice husk ash and the dispersion of rice husk ash, thereby improving the grinding aid performance of the grinding aid.

[0120] Combining the data of Example 15, Comparative Example 2 and Table 4, it can be seen that after modification with triethanolamine, the grinding aid effect of the grinding aid can be effectively improved, and the mechanical strength of the cement can be improved. This is mainly because after modification with triethanolamine, it is conducive to its adsorption to the cement surface and continuous penetration into the microcracks of the solid particles, which can expand the old cracks and continuously generate new microcracks, making it easier to be ground into particles with smaller particle size to further improve the grinding aid performance.

[0121] Combining the data of Example 15, Comparative Examples 3-4 and Table 4, it can be seen that the grinding aid prepared by the joint action of rice husk ash, modified triethanolamine and triisopropanolamine has better grinding aid performance and can effectively improve the strength of cement. In addition, after replacing the ethanolamine with ethylene glycol and propylene glycol, the grinding aid performance of the grinding aid decreases and the strength of cement decreases. This may be because both p-aminophenol and calcium lignin sulfonate molecules cannot play a coordinated role with the ethanolamine, resulting in a decrease in the grinding aid performance of the grinding aid and a decrease in the strength of the cement.

[0122] Combining the data of Example 15, Comparative Examples 5-6 and Table 4, it can be seen that rice husk ash can be used as a cement grinding aid to effectively improve the grinding performance of the grinding aid, and can also be combined with modified triethanolamine, triisopropanolamine and calcium lignin sulfonate to improve the mechanical strength of cement.

[0123] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A powder grinding aid, characterized in that: The invention comprises the following raw materials in parts by weight which are mixed and dried: 50 parts of rice husk ash, 5 parts of modified triethanolamine, 5 parts of triisopropanolamine, 5-8 parts of water and 2-3 parts of calcium lignin sulfonate; wherein the particle size of the rice husk ash is 1-2 microns; 3-5 parts by weight of an auxiliary agent is added, wherein the auxiliary agent comprises p-aminophenol and sodium thiocyanate in a mass ratio of (2-3):1; and fly ash is added, wherein the mass ratio of the rice husk ash to the fly ash is (3-5):

1.

2. A powder grinding aid according to claim 1, characterized in that: The modified triethanolamine comprises the following preparation steps: stirring and mixing triethanolamine and glacial acetic acid, dropping concentrated sulfuric acid as a catalyst, and then heating to 130-140° C. and reflux, and after the reaction is completed, cooling to obtain the modified triethanolamine, wherein the mass ratio of triethanolamine to glacial acetic acid is (3-5):

1.

3. A method for preparing a powder grinding aid according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1: adding modified triethanolamine and triisopropanolamine into water to prepare liquid alcoholamine; S2: Mix liquid alcoholamine, rice husk ash and calcium lignin sulfonate, stir evenly and then dry to obtain a powder grinding aid.

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