A new type of quaternary ammonium salt grinding aid and its application in cement

Abstract

The present invention belongs to the technical field of cement production, and specifically relates to a novel quaternary ammonium salt grinding aid and its application in cement. The novel quaternary ammonium salt grinding aid prepared by the present invention can enhance the grinding aid effect of cement and improve the mechanical properties of cement. On the one hand, the grinding aid prepared by the present invention introduces multiple hydroxyl groups and quaternary ammonium salts. Its unique molecular structure and polarity enable it to be well adsorbed on the surface of cement particles, shielding charges, and providing a good grinding aid effect, thereby achieving a good dispersion effect and improving the fineness of cement. On the other hand, the grinding aid of the present invention can better promote the hydration rate of cement clinker, produce more hydration products, make the bulk structure of the cement hydration products more compact, and thus improve the mechanical properties of cement.

Description

Technical Field

[0001] The invention belongs to the technical field of cement production, and particularly relates to a novel quaternary ammonium salt grinding aid and application thereof in cement. Background Art

[0002] my country is a major cement producer, and cement plays a crucial role in national economic development, with widespread application in defense projects, bridge and road construction, and residential and commercial construction. The main cement production process consists of three steps: raw material grinding, clinker calcination, and cement clinker grinding. Grinding consumes the most energy within this process, and energy losses are very high, resulting in a very low energy utilization rate. Clinker grinding accounts for at least half of the total energy consumed, with only a small portion going towards increasing material fineness, while the vast majority is wasted. This is because material fineness continuously increases during the grinding process. If cement is not discharged from the mill in a timely manner after reaching sufficient fineness, a cushioning effect will form, causing the material within the mill to collide and grind again, consuming even more energy. Furthermore, the adhesion and interfacial tension of the powder increase with increasing fineness, leading to the healing of existing cracks in the particles and increased energy consumption for further grinding. All of these factors can severely impact the grinding efficiency of the grinding equipment and significantly reduce energy utilization. In cement production, since energy consumption and grinding efficiency are the main factors restricting its development, improving its grinding efficiency and reducing energy consumption have become the top priorities that the cement industry urgently needs to solve.

[0003] To improve grinding efficiency, reduce energy consumption, and conserve energy, domestic cement companies currently employ two common approaches. One involves improving the mechanical structure of the grinding system, thereby enhancing the grinding method and process flow to achieve energy savings. The other involves adding a small amount of grinding aid to the grinding material. While the first approach can improve grinding efficiency and reduce energy consumption to a certain extent, it generally requires additional machinery and equipment, significantly increasing the investment cost of cement production. The second approach, on the other hand, is simple to operate, requires minimal investment, and delivers rapid results, significantly improving cement properties.

[0004] CN116396447B discloses a preparation method and application of a polymer cement grinding aid. However, the polymer cement grinding aid has a complex process, high cost, and its mechanical properties need to be improved.

[0005] CN108467456B discloses a polycarboxylic acid polyol ester cement grinding aid and a preparation method thereof. However, the grinding aid is also a polymer material, which is relatively expensive and not suitable for industrial production.

[0006] Based on this, there is an urgent need to develop a new grinding aid that can improve the cement grinding effect and improve the mechanical properties of cement. Summary of the Invention

[0007] In view of the problems existing in the prior art, the object of the present invention is to provide a novel quaternary ammonium salt grinding aid that can improve the grinding effect of cement and improve the mechanical properties of cement. The present invention is achieved by the following technical solutions:

[0008] A novel quaternary ammonium salt grinding aid, which is a compound represented by formula (I):

[0009]

[0010] Where R is C 1-6 Alkyl or C 3-8 Cycloalkyl, X is Cl, Br, I, BF4 or CF3SO3.

[0011] In some embodiments, R is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, cyclopropyl, cyclobutyl, or cyclopentyl.

[0012] In some embodiments, X is Cl, Br, or I.

[0013] In some embodiments, it is a compound having one of the following structures:

[0014]

[0015] In some embodiments, the preparation method of the novel quaternary ammonium grinding aid comprises the following steps:

[0016] Compound (II) and compound (III) are subjected to quaternization reaction to obtain a compound represented by formula (I), and the reaction formula is as follows:

[0017]

[0018] In some embodiments, the reaction solvent is selected from one or more of water, methanol, ethanol, and isopropanol.

[0019] In some embodiments, the molar ratio of compound (II) to compound (III) is (2.0-2.5):1; the reaction temperature is 50-80° C., and the reaction time is 5-10 h.

[0020] The present invention also protects a cement composition comprising the novel quaternary ammonium salt grinding aid.

[0021] In some embodiments, the cement composition comprises clinker, gypsum, limestone, fly ash, slag and a novel quaternary ammonium grinding aid.

[0022] The present invention also protects the application of the novel quaternary ammonium salt grinding aid in cement.

[0023] The present invention has achieved the following beneficial effects:

[0024] 1) The novel quaternary ammonium salt grinding aid prepared by the present invention can improve the grinding effect of cement and improve the mechanical properties of cement, and its effect is far superior to the common triethanolamine grinding aid in the prior art.

[0025] 2) The grinding aid prepared by the present invention introduces multiple hydroxyl groups and quaternary ammonium salts. Its unique molecular structure and polarity enable it to be well adsorbed on the surface of cement particles, shielding charges, playing a good grinding aid effect, thereby playing a good dispersing effect and improving the fineness of cement; on the other hand, the grinding aid of the present invention can better promote the hydration rate of cement clinker, produce more hydration products, make the cement hydration product body structure more dense, thereby improving the mechanical properties of cement. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] The endpoints and any values ​​of the ranges described herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0028] Preparation Example 1: Preparation of Novel Quaternary Ammonium Salt Grinding Aid A

[0029]

[0030] Anhydrous ethanol (300 mL) was added to a three-necked flask equipped with a stirrer and a reflux condenser, followed by the raw material compound 1 (50.0 g, 0.22 mol) and 1,3-dibromopropane (20.0 g, 0.1 mol). The mixture was heated to 75°C and stirred under reflux for 5 hours. After completion of the reaction, the mixture was cooled to room temperature and concentrated by vacuum distillation to obtain a pale yellow viscous substance. The product was then washed three times with a mixed solvent of ethyl acetate and acetone in a volume ratio of 1:2. The white solid was filtered and dried in vacuo at 100°C to obtain the new quaternary ammonium grinding aid A with a yield of 71.5%.

[0031] 1H NMR (400MHz, DMSO-d6): δ5.45(s,4H),3.55-3.50(m,4H),2.61-2.54(m,4H),2.40-2 .36(m,4H),2.25(s,6H),1.57-1.46(m,16H),1.40-1.35(m,2H),1.23-1.11(m,16H).

[0032] In addition, new quaternary ammonium grinding aids B, C, and D can be prepared using a similar method.

[0033] 1) Preparation of new quaternary ammonium salt grinding aid B

[0034]

[0035] Anhydrous ethanol (300 mL) was added to a three-necked flask equipped with a stirrer and a reflux condenser, followed by the raw material compound 1 (50.0 g, 0.22 mol) and 1,3-dichloropropane (11.3 g, 0.1 mol). The mixture was heated to 70°C and stirred under reflux for 7 hours. After completion of the reaction, the mixture was cooled to room temperature and concentrated by vacuum distillation to obtain a pale yellow viscous substance. The product was then washed three times with a mixed solvent of ethyl acetate and acetone in a volume ratio of 1:2. The white solid was filtered and dried in vacuo at 100°C to obtain the new quaternary ammonium grinding aid B with a yield of 64.2%.

[0036] 2) Preparation of new quaternary ammonium salt grinding aid C

[0037]

[0038] Anhydrous ethanol (300 mL) was added to a three-necked flask equipped with a stirrer and a reflux condenser, followed by the raw material compound 2 (53.0 g, 0.22 mol) and 1,3-dibromopropane (20.0 g, 0.1 mol). The mixture was heated to 75°C and stirred under reflux for 5 hours. After completion of the reaction, the mixture was cooled to room temperature and concentrated by vacuum distillation to obtain a pale yellow viscous substance. The product was then washed three times with a mixed solvent of ethyl acetate and acetone in a volume ratio of 1:2. The white solid was filtered and dried in vacuo at 100°C to obtain the new quaternary ammonium grinding aid C with a yield of 67.9%.

[0039] 3) Preparation of new quaternary ammonium salt grinding aid D

[0040]

[0041] Anhydrous ethanol (300 mL) was added to a three-necked flask equipped with a stirrer and a reflux condenser, followed by the raw material compound 2 (53.0 g, 0.22 mol) and 1,3-dichloropropane (11.3 g, 0.1 mol). The mixture was heated to 70°C and stirred under reflux for 7 hours. After completion of the reaction, the mixture was cooled to room temperature and concentrated by vacuum distillation to obtain a pale yellow viscous substance. The product was then washed three times with a mixed solvent of ethyl acetate and acetone in a volume ratio of 1:2. The white solid was filtered and dried in vacuo at 100°C to obtain the new quaternary ammonium grinding aid D with a yield of 62.7%.

[0042] Application Examples

[0043] Take the new quaternary ammonium grinding aid A, the new quaternary ammonium grinding aid D, and the common quaternary ammonium grinding aid triethanolamine, refer to the following cement mix ratio to prepare samples, and test the relevant properties:

[0044] The cement mix (by mass fraction) was: clinker 70%, gypsum 5%, limestone 6%, fly ash 9%, and slag 10%. Grinding conditions: 500 mm x 500 mm ball mill, 0.05% grinding aid (relative to the total weight of cement), grinding for 40 min.

[0045] The performance test method is as follows:

[0046] 1) Determine cement fineness using the water sieving method specified in GB 1345-2005, "Test Method for Cement Fineness" (80 μm Sieve Analysis Method). The experimental steps are as follows: Before the sieving test, check that the water is free of mud and sand. Adjust the water pressure and the position of the water sieve rack for proper operation, and maintain a distance of 35 mm to 75 mm between the nozzle bottom and the sieve. Weigh the sample to the nearest 0.01 g and place it in a clean water sieve. Immediately rinse with fresh water until most of the fine powder has passed through. Place the sample on the water sieve rack and rinse continuously with a nozzle at a water pressure of 0.05 MPa ± 0.02 MPa for 3 minutes. After sieving, rinse the residue with a small amount of water into an evaporating dish. Once all cement particles have settled, carefully pour out the clean water, dry the sample, and weigh the residue using a balance.

[0047] 2) The flexural strength of cement mortar was determined according to GB / T17671-2021 "Test method for strength of cement mortar (ISO method)". The experimental steps were as follows: the mortar that met the consistency requirements was made into a 40mmx40mmx160mm prism specimen, placed in a standard curing box with a constant temperature of 25°C and a relative humidity of 95%, and cured for 3d and 28d respectively, and then measured.

[0048] 3) The compressive strength of cement mortar was determined according to GB / T17671-2021, "Test Method for Strength of Cement Mortar (ISO Method)." The following experimental steps were used: A 40mm x 40mm x 160mm prism specimen model was used. Mortar meeting the required consistency was formed into a module and placed in a standard curing chamber maintained at a constant temperature of 25°C and a relative humidity of 95%. The modules were cured for 3 and 28 days, respectively, and the compressive strength of the cement mortar was determined. During the test, the center of the half-prism and the center of the press plate should be within ±0.5mm. The protrusion of the prism outside the platen should be approximately 10mm. Loading was applied uniformly at a rate of 2400±200N / s until failure.

[0049] The test results are shown in Table 1:

[0050] Table 1 Cement performance test results

[0051]

[0052]

[0053] As shown in Table 1, the novel quaternary ammonium salt grinding aid prepared by the present invention can improve the grinding aid effect of cement, and improve the mechanical property of cement, and its effect is far superior to the common triethanolamine grinding aid of prior art. The main reason is that: on the one hand, the grinding aid prepared by the present invention introduces multiple hydroxyls and quaternary ammonium salt, and its unique molecular structure and polarity enable it to be well adsorbed on the cement particle surface, shielding charge, playing a good grinding aid effect, thereby playing a good dispersing effect, improving the fineness of cement; on the other hand, the grinding aid of the present invention can better promote the hydration speed of cement clinker, produce more hydration products, make the cement hydration product body structure more dense, thereby improving the mechanical property of cement.

[0054] The above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A novel quaternary ammonium salt grinding aid, which is a compound shown in formula (I): in, R is C 1-6 Alkyl or C 3-8 Cycloalkyl, X is Cl, Br, I, BF4 or CF3SO3.

2. The novel quaternary ammonium salt according to claim 1, wherein R is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, cyclopropyl, cyclobutyl or cyclopentyl.

3. The novel quaternary ammonium salt according to claim 1, wherein X is Cl, Br, or I.

4. novel quaternary ammonium salt according to claim 1, it is a compound with one of the following structures:

5. a preparation method of the novel quaternary ammonium salt grinding aid according to claim 1, comprising the steps of: Compound (II) and compound (III) are subjected to quaternization reaction to obtain a compound represented by formula (I), and the reaction formula is as follows: Wherein, R and X are defined as in claim 1.

6. The method according to claim 5, characterized in that The reaction solvent is selected from one or more of water, methanol, ethanol and isopropanol.

7. The method according to claim 5, characterized in that The molar ratio of the compound (II) to the compound (III) is (2.0-2.5):1; the reaction temperature is 50-80° C., and the reaction time is 5-10 h.

8. A cement composition, characterized in that The novel quaternary ammonium salt grinding aid comprises the novel quaternary ammonium salt grinding aid according to any one of claims 1 to 4.

9. The cement composition according to claim 8, characterized in that Contains clinker, gypsum, limestone, fly ash, slag and a new type of quaternary ammonium salt grinding aid.

10. Use of the novel quaternary ammonium salt grinding aid according to any one of claims 1 to 4 in cement.

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