Preparation method of a demulsifier and application thereof in asphalt mixture

Abstract

The application belongs to the technical field of demulsification dehydration, and discloses a preparation method of a demulsifier and application of the demulsifier in asphalt mixture. The preparation method of the demulsifier comprises the following steps: reacting acidified clay minerals with gamma-methacryloxypropyltrimethoxysilane to obtain modified clay minerals; reacting the modified clay minerals with triethylenetetramine to obtain polyamine-based clay minerals; and reacting the polyamine-based clay minerals with bromohexadecane to obtain the demulsifier. The demulsifier is a polyquaternary ammonium salt type cationic demulsifier. Through the positive charges of cations contained on the surface of the clay minerals and quaternary ammonium salts, the double electric layer structure of the surface of anionic emulsified asphalt is changed, the thickness of the double electric layer is compressed, the electrostatic repulsion between the emulsified asphalts is reduced, and the demulsification effect is good. When the asphalt mixture is prepared, the adhesion of asphalt particles to aggregates can be effectively promoted, the water in the asphalt mixture can be effectively discharged, and the solidification and molding of the asphalt mixture can be accelerated.

Description

A method for preparing a demulsifier and its application in asphalt mixtures. Technical Field

[0001] This invention belongs to the field of demulsification and dehydration technology, specifically relating to a method for preparing a demulsifier and its application in asphalt mixtures. Background Technology

[0002] With the rapid growth of my country's economy, highway construction has progressed by leaps and bounds. Asphalt pavement, due to its advantages such as smooth surface, good elasticity and plasticity, low dust, impermeability, and durability, has become one of the most widely used high-grade pavements in road construction. Therefore, asphalt holds a prominent position in highway construction and pavement maintenance.

[0003] Emulsified asphalt can be stored stably for a long time and can be mixed with aggregate mixtures at room temperature before being paved and compacted to form asphalt pavement. Therefore, in many road construction applications, emulsified asphalt provides a safer, more energy-efficient, and more environmentally friendly system than hot asphalt because this process avoids high-temperature operation, heating, and harmful emissions. However, the emulsifiers in asphalt can form a high-strength, dense interfacial film with water, resulting in weak adhesion between the asphalt and the aggregates in the asphalt mixture. This is especially true for anionic emulsified asphalt, which, along with the negatively charged aggregates, repels each other, further reducing adhesion and thus increasing the road surface curing time and slowing down the construction process.

[0004] Li Xinyue et al.'s "Research on Anionic Emulsified Asphalt Demulsifiers" discloses a method using positively charged cationic inorganic salts as anionic emulsified asphalt demulsifiers. However, using only inorganic salts as demulsifiers results in unsatisfactory demulsification effects. Furthermore, using inorganic salts as demulsifiers requires dilution with water, and the amount of water and ambient temperature both affect the demulsification time, necessitating the exploration of a balance between water volume and ambient temperature. Chinese patent CN109929584B discloses a clay mineral demulsifier, prepared by reacting amino-modified clay minerals with ferric chloride, sodium citrate, ethylene glycol, and polyethylene glycol. This clay mineral demulsifier is applied to oil-in-water crude oil emulsions, utilizing the amphiphilic nature of the demulsifier, but its demulsification effect on anionic emulsified asphalt is poor. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing a demulsifier to solve the problem of poor demulsification effect of anionic emulsified asphalt in existing technologies.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a demulsifier includes the following steps:

[0008] Step 1: Disperse the acidified clay minerals (CM) in xylene, add γ-methacryloxypropyltrimethoxysilane dropwise, and after the addition is complete, allow the reaction to proceed. After the reaction is complete, filter, wash, and dry to obtain the modified clay minerals.

[0009] Step 2: Disperse the modified clay minerals in N,N-dimethylformamide, add triethylenetetramine dropwise, and after the addition is complete, allow the reaction to proceed. After the reaction is complete, filter, wash, and dry to obtain polytert-amine clay minerals.

[0010] Step 3: Disperse the polytert-amine clay minerals in N,N-dimethylformamide, add hexadecane bromide dropwise, and after the addition is complete, allow the reaction to proceed. After the reaction is complete, filter, wash, and dry to obtain the demulsifier.

[0011] The demulsifier is a polyquaternary ammonium salt type cationic demulsifier.

[0012] Preferably, in step one, the acidified clay mineral is prepared by the following steps: placing the clay mineral in an acid solution for impregnation, filtering, washing, and drying after impregnation to obtain the acidified clay mineral.

[0013] Preferably, the mass ratio of clay minerals to acid is 1:(5-10).

[0014] Preferably, the impregnation conditions are impregnation at 75-85°C for 2-3 hours.

[0015] Preferably, the acid solution comprises an aqueous solution of hydrochloric acid, wherein the aqueous solution of hydrochloric acid comprises a 10 wt% aqueous solution of hydrochloric acid;

[0016] The clay minerals include montmorillonite.

[0017] Preferably, in step one, the mass ratio of the acidified clay mineral, xylene, and γ-methacryloyloxypropyltrimethoxysilane is 10:(100-150):(15-25).

[0018] Preferably, in step one, the reaction conditions are a reaction at 50-70°C for 3-5 hours.

[0019] Furthermore, the dropping time of the γ-methacryloxypropyltrimethoxysilane is 30-60 min.

[0020] Preferably, in step two, the mass ratio of modified clay mineral, N,N-dimethylformamide, and triethylenetetramine is (25-35):(300-500):(1.5-2.5).

[0021] Furthermore, the addition time of the triethylenetetramine is 30-60 minutes.

[0022] Preferably, in step two, the reaction conditions are a reaction at 20-30°C for 18-36 hours.

[0023] Furthermore, because the clay minerals undergo acidification, their surfaces produce more hydroxyl groups, making them more reactive with γ-methacryloyloxypropyltrimethoxysilane.

[0024] Preferably, in step three, the mass ratio of polytert-amine clay mineral, N,N-dimethylformamide, and hexadecane is (26.5-37.5):(500-800):(18.5-31).

[0025] Furthermore, the dropping time of the hexadecane bromide is 30-60 min.

[0026] Preferably, in step three, the reaction conditions are a reaction at 80-120°C for 6-8 hours.

[0027] Preferably, the application of a demulsifier prepared using the above-described demulsifier preparation method in asphalt mixtures.

[0028] The surface of clay minerals contains Ca 2+ Mg 2+ The presence of cations alters the double-layer structure of anionic emulsified asphalt, affecting its stability and thus having a demulsifying effect.

[0029] Quaternary ammonium salt demulsifiers are cationic demulsifiers. The cations in the demulsifier can change the double electric layer structure on the surface of anionic emulsified asphalt, thus affecting the stability of anionic emulsified asphalt.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] The demulsifier of the present invention is prepared by combining clay minerals with multi-quaternary ammonium salts. The positive charge of the cations on the surface of the clay minerals and the positive charge of the quaternary ammonium salts in the demulsifier can change the double electric layer structure on the surface of anionic emulsified asphalt, compress the double electric layer thickness, reduce the electrostatic repulsion between emulsified asphalt, and achieve good demulsification effect.

[0032] In this invention, clay minerals are reacted with γ-methacryloxypropyltrimethoxysilane to obtain modified clay minerals. Acryloxy groups are introduced, and the modified clay minerals undergo a Michael addition reaction with triethylenetetramine to obtain polytert-amine clay minerals. These polytert-amine clay minerals are then subjected to a quaternization reaction to obtain a polyquaternary ammonium salt-type demulsifier. Under the synergistic effect of quaternary ammonium salt ions and long hydrocarbon chains, the demulsifier exhibits good amphiphilicity, which can disrupt the interfacial film between the emulsifier and water, enhancing demulsification performance. Furthermore, the polyquaternary ammonium salt-type demulsifier demonstrates excellent demulsification performance for anionic emulsified asphalt. Finally, the clay minerals are linked to the polyquaternary ammonium salt structure through stable chemical bonds, increasing the compatibility and dispersion uniformity of inorganic clay minerals in emulsified asphalt and promoting demulsification. During the preparation of asphalt mixtures, it effectively promotes the adhesion between asphalt particles and aggregates, facilitates the removal of moisture from the asphalt mixture, and accelerates the solidification and molding of the asphalt mixture. Attached Figure Description

[0033] Figure 1 shows the preparation process flow of the demulsifier in this invention;

[0034] Figure 2 is a line graph showing the demulsification performance test results of the demulsifiers prepared in Examples 1-8 and Comparative Examples 1-2 of the present invention. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] Example 1

[0037] A method for preparing a demulsifier includes the following steps:

[0038] Step 1: Place montmorillonite in a 10wt% hydrochloric acid aqueous solution with a mass ratio of 1:5. Soak at 75℃ for 3 hours. After soaking, filter, wash with water, and dry in a vacuum drying oven at 50℃ for 10 hours to obtain acidified montmorillonite.

[0039] Step 2: Disperse the acidified montmorillonite in xylene, and add γ-methacryloxypropyltrimethoxysilane dropwise. The mass ratio of acidified montmorillonite, xylene, and γ-methacryloxypropyltrimethoxysilane is 10:100:15. The dropwise addition time of γ-methacryloxypropyltrimethoxysilane is 30 min. After the dropwise addition is complete, react at 50 °C for 5 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50 °C for 10 h to obtain modified montmorillonite.

[0040] Step 3: Disperse the modified montmorillonite in N,N-dimethylformamide, and add triethylenetetramine dropwise. The mass ratio of modified montmorillonite, N,N-dimethylformamide, and triethylenetetramine is 25:300:1.5. The addition time of triethylenetetramine is 30 min. After the addition is complete, react at 20℃ for 36 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain polytert-amine montmorillonite.

[0041] Step 4: Disperse polytert-amine montmorillonite in N,N-dimethylformamide, and add hexadecane dropwise. The mass ratio of polytert-amine montmorillonite, N,N-dimethylformamide, and hexadecane is 26.5:500:18.5. The dropwise addition time of hexadecane is 30 min. After the addition is complete, react at 80℃ for 8 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain the demulsifier.

[0042] Example 2

[0043] A method for preparing a demulsifier includes the following steps:

[0044] Step 1: Place montmorillonite in a 10wt% hydrochloric acid aqueous solution with a mass ratio of 1:10 and soak at 85℃ for 2 hours. After soaking, filter, wash with water, and dry in a vacuum drying oven at 50℃ for 10 hours to obtain acidified montmorillonite.

[0045] Step 2: Disperse the acidified montmorillonite in xylene, and add γ-methacryloxypropyltrimethoxysilane dropwise. The mass ratio of acidified montmorillonite, xylene, and γ-methacryloxypropyltrimethoxysilane is 10:150:25. The dropwise addition time of γ-methacryloxypropyltrimethoxysilane is 60 min. After the dropwise addition is complete, react at 70℃ for 3 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain modified montmorillonite.

[0046] Step 3: Disperse the modified montmorillonite in N,N-dimethylformamide, and add triethylenetetramine dropwise. The mass ratio of modified montmorillonite, N,N-dimethylformamide, and triethylenetetramine is 35:500:2.5. The addition time of triethylenetetramine is 60 min. After the addition is complete, react at 30℃ for 18 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain polytert-amine montmorillonite.

[0047] Step 4: Disperse polytert-amine montmorillonite in N,N-dimethylformamide, and add hexadecane bromodropwise. The mass ratio of polytert-amine montmorillonite, N,N-dimethylformamide, and hexadecane bromodropwise is 37.5:800:31. The hexadecane bromodropwise addition time is 60 min. After the addition is complete, react at 120℃ for 6 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain the demulsifier.

[0048] Example 3

[0049] A method for preparing a demulsifier includes the following steps:

[0050] Step 1: Place montmorillonite in a 10wt% hydrochloric acid aqueous solution with a mass ratio of 1:6. Soak at 80℃ for 2.5 hours. After soaking, filter, wash with water, and dry in a vacuum drying oven at 50℃ for 10 hours to obtain acidified montmorillonite.

[0051] Step 2: Disperse the acidified montmorillonite in xylene, and add γ-methacryloxypropyltrimethoxysilane dropwise. The mass ratio of acidified montmorillonite, xylene, and γ-methacryloxypropyltrimethoxysilane is 10:105:16. The dropwise addition time of γ-methacryloxypropyltrimethoxysilane is 35 min. After the addition is complete, react at 55℃ for 4.5 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain modified montmorillonite.

[0052] Step 3: Disperse the modified montmorillonite in N,N-dimethylformamide, and add triethylenetetramine dropwise. The mass ratio of modified montmorillonite, N,N-dimethylformamide, and triethylenetetramine is 26.5:330:1.65. The addition time of triethylenetetramine is 35 min. After the addition is complete, react at 25°C for 24 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50°C for 10 h to obtain polytert-amine montmorillonite.

[0053] Step 4: Disperse polytert-amine montmorillonite in N,N-dimethylformamide, and add hexadecane bromide dropwise. The mass ratio of polytert-amine montmorillonite, N,N-dimethylformamide, and hexadecane bromide is 28:545:20. The dropwise addition time of hexadecane bromide is 35 min. After the dropwise addition is complete, react at 85℃ for 7.5 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain the demulsifier.

[0054] Example 4

[0055] A method for preparing a demulsifier includes the following steps:

[0056] Step 1: Place montmorillonite in a 10wt% hydrochloric acid aqueous solution with a mass ratio of 1:7. Soak at 80℃ for 2.5 hours. After soaking, filter, wash with water, and dry in a vacuum drying oven at 50℃ for 10 hours to obtain acidified montmorillonite.

[0057] Step 2: Disperse the acidified montmorillonite in xylene, and add γ-methacryloxypropyltrimethoxysilane dropwise. The mass ratio of acidified montmorillonite, xylene, and γ-methacryloxypropyltrimethoxysilane is 10:115:18. The dropwise addition time of γ-methacryloxypropyltrimethoxysilane is 40 min. After the dropwise addition is complete, react at 50 °C for 4.5 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50 °C for 10 h to obtain modified montmorillonite.

[0058] Step 3: Disperse the modified montmorillonite in N,N-dimethylformamide, and add triethylenetetramine dropwise. The mass ratio of modified montmorillonite, N,N-dimethylformamide, and triethylenetetramine is 28:350:1.8. The addition time of triethylenetetramine is 40 min. After the addition is complete, react at 25°C for 24 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50°C for 10 h to obtain polytert-amine montmorillonite.

[0059] Step 4: Disperse polytert-amine montmorillonite in N,N-dimethylformamide, and add hexadecane bromide dropwise. The mass ratio of polytert-amine montmorillonite, N,N-dimethylformamide, and hexadecane bromide is 29.5:590:22. The dropwise addition time of hexadecane bromide is 40 min. After the dropwise addition is complete, react at 90℃ for 7.5 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain the demulsifier.

[0060] Example 5

[0061] A method for preparing a demulsifier includes the following steps:

[0062] Step 1: Place montmorillonite in a 10wt% hydrochloric acid aqueous solution with a mass ratio of 1:7.5 and soak at 80℃ for 2.5 hours. After soaking, filter, wash with water, and dry in a vacuum drying oven at 50℃ for 10 hours to obtain acidified montmorillonite.

[0063] Step 2: Disperse the acidified montmorillonite in xylene, and add γ-methacryloxypropyltrimethoxysilane dropwise. The mass ratio of acidified montmorillonite, xylene, and γ-methacryloxypropyltrimethoxysilane is 10:120:20. The dropwise addition time of γ-methacryloxypropyltrimethoxysilane is 45 min. After the dropwise addition is complete, react at 60℃ for 4 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain modified montmorillonite.

[0064] Step 3: Disperse the modified montmorillonite in N,N-dimethylformamide, and add triethylenetetramine dropwise. The mass ratio of modified montmorillonite, N,N-dimethylformamide, and triethylenetetramine is 29.5:375:1.95. The addition time of triethylenetetramine is 45 min. After the addition is complete, react at 25°C for 24 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50°C for 10 h to obtain polytert-amine montmorillonite.

[0065] Step 4: Disperse polytert-amine montmorillonite in N,N-dimethylformamide, and add hexadecane dropwise. The mass ratio of polytert-amine montmorillonite, N,N-dimethylformamide, and hexadecane is 31:635:23.5. The dropwise addition time of hexadecane is 45 min. After the addition is complete, react at 100℃ for 7 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain the demulsifier.

[0066] Example 6

[0067] A method for preparing a demulsifier includes the following steps:

[0068] Step 1: Place montmorillonite in a 10wt% hydrochloric acid aqueous solution with a mass ratio of 1:7.5 and soak at 80℃ for 2.5 hours. After soaking, filter, wash with water, and dry in a vacuum drying oven at 50℃ for 10 hours to obtain acidified montmorillonite.

[0069] Step 2: Disperse the acidified montmorillonite in xylene, and add γ-methacryloxypropyltrimethoxysilane dropwise. The mass ratio of acidified montmorillonite, xylene, and γ-methacryloxypropyltrimethoxysilane is 10:125:22. The dropwise addition time of γ-methacryloxypropyltrimethoxysilane is 45 min. After the addition is complete, react at 60℃ for 4 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain modified montmorillonite.

[0070] Step 3: Disperse the modified montmorillonite in N,N-dimethylformamide, and add triethylenetetramine dropwise. The mass ratio of modified montmorillonite, N,N-dimethylformamide, and triethylenetetramine is 31:400:2.1. The addition time of triethylenetetramine is 45 min. After the addition is complete, react at 25°C for 24 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50°C for 10 h to obtain polytert-amine montmorillonite.

[0071] Step 4: Disperse polytert-amine montmorillonite in N,N-dimethylformamide, and add hexadecane dropwise. The mass ratio of polytert-amine montmorillonite, N,N-dimethylformamide, and hexadecane is 32.5:680:25. The dropwise addition time of hexadecane is 45 min. After the addition is complete, react at 100℃ for 7 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain the demulsifier.

[0072] Example 7

[0073] A method for preparing a demulsifier includes the following steps:

[0074] Step 1: Place montmorillonite in a 10wt% hydrochloric acid aqueous solution with a mass ratio of 1:8. Soak at 80℃ for 2.5 hours. After soaking, filter, wash with water, and dry in a vacuum drying oven at 50℃ for 10 hours to obtain acidified montmorillonite.

[0075] Step 2: Disperse the acidified montmorillonite in xylene, and add γ-methacryloxypropyltrimethoxysilane dropwise. The mass ratio of acidified montmorillonite, xylene, and γ-methacryloxypropyltrimethoxysilane is 10:130:23. The dropwise addition time of γ-methacryloxypropyltrimethoxysilane is 50 min. After the addition is complete, react at 65℃ for 3.5 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain modified montmorillonite.

[0076] Step 3: Disperse the modified montmorillonite in N,N-dimethylformamide, and add triethylenetetramine dropwise. The mass ratio of modified montmorillonite, N,N-dimethylformamide, and triethylenetetramine is 32.5:435:2.25. The addition time of triethylenetetramine is 50 min. After the addition is complete, react at 25°C for 24 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50°C for 10 h to obtain polytert-amine montmorillonite.

[0077] Step 4: Disperse polytert-amine montmorillonite in N,N-dimethylformamide, and add hexadecane dropwise. The mass ratio of polytert-amine montmorillonite, N,N-dimethylformamide, and hexadecane is 34:720:27. The dropwise addition time of hexadecane is 50 min. After the addition is complete, react at 110℃ for 6.5 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain the demulsifier.

[0078] Example 8

[0079] A method for preparing a demulsifier includes the following steps:

[0080] Step 1: Place montmorillonite in a 10wt% hydrochloric acid aqueous solution with a mass ratio of 1:9. Soak at 80℃ for 2.5 hours. After soaking, filter, wash with water, and dry in a vacuum drying oven at 50℃ for 10 hours to obtain acidified montmorillonite.

[0081] Step 2: Disperse the acidified montmorillonite in xylene, and add γ-methacryloxypropyltrimethoxysilane dropwise. The mass ratio of acidified montmorillonite, xylene, and γ-methacryloxypropyltrimethoxysilane is 10:140:24. The dropwise addition time of γ-methacryloxypropyltrimethoxysilane is 55 min. After the addition is complete, react at 65℃ for 3.5 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain modified montmorillonite.

[0082] Step 3: Disperse the modified montmorillonite in N,N-dimethylformamide, and add triethylenetetramine dropwise. The mass ratio of modified montmorillonite, N,N-dimethylformamide, and triethylenetetramine is 34:470:2.4. The addition time of triethylenetetramine is 55 min. After the addition is complete, react at 25°C for 24 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50°C for 10 h to obtain polytert-amine montmorillonite.

[0083] Step 4: Disperse polytert-amine montmorillonite in N,N-dimethylformamide, and add hexadecane dropwise. The mass ratio of polytert-amine montmorillonite, N,N-dimethylformamide, and hexadecane is 36:760:28.5. The dropwise addition time of hexadecane is 55 min. After the addition is complete, react at 115℃ for 6.5 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain the demulsifier.

[0084] Comparative Example 1

[0085] A method for preparing a demulsifier includes the following steps:

[0086] Step 1: Disperse montmorillonite in xylene, and add γ-methacryloxypropyltrimethoxysilane dropwise. The mass ratio of montmorillonite, xylene, and γ-methacryloxypropyltrimethoxysilane is 10:100:15. The dropwise addition time of γ-methacryloxypropyltrimethoxysilane is 30 min. After the dropwise addition is complete, react at 50 °C for 5 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50 °C for 10 h to obtain modified montmorillonite.

[0087] Step 2: Disperse the modified montmorillonite in N,N-dimethylformamide, and add triethylenetetramine dropwise. The mass ratio of modified montmorillonite, N,N-dimethylformamide, and triethylenetetramine is 25:300:1.5. The addition time of triethylenetetramine is 30 min. After the addition is complete, react at 20°C for 36 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50°C for 10 h to obtain polytert-amine montmorillonite.

[0088] Step 3: Disperse polytert-amine montmorillonite in N,N-dimethylformamide, and add hexadecane bromide dropwise. The mass ratio of polytert-amine montmorillonite, N,N-dimethylformamide, and hexadecane bromide is 26.5:500:18.5. The dropwise addition time of hexadecane bromide is 30 min. After the dropwise addition is complete, react at 80℃ for 8 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50℃ for 10 h to obtain the demulsifier.

[0089] Comparative Example 2

[0090] A method for preparing a demulsifier includes the following steps:

[0091] Step 1: Place montmorillonite in a 10wt% hydrochloric acid aqueous solution with a mass ratio of 1:5. Soak at 75℃ for 3 hours. After soaking, filter, wash with water, and dry in a vacuum drying oven at 50℃ for 10 hours to obtain acidified montmorillonite.

[0092] Step 2: Disperse the acidified montmorillonite in xylene, and add γ-methacryloxypropyltrimethoxysilane dropwise. The mass ratio of acidified montmorillonite, xylene, and γ-methacryloxypropyltrimethoxysilane is 10:100:15. The dropwise addition time of γ-methacryloxypropyltrimethoxysilane is 30 min. After the dropwise addition is complete, react at 50 °C for 5 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50 °C for 10 h to obtain modified montmorillonite.

[0093] Step 3: Disperse the modified montmorillonite in N,N-dimethylformamide, and add triethylenetetramine dropwise. The mass ratio of modified montmorillonite, N,N-dimethylformamide, and triethylenetetramine is 25:300:1.5. The addition time of triethylenetetramine is 30 min. After the addition is complete, react at 20°C for 36 h. After the reaction is complete, filter, wash with ethanol, and dry in a vacuum drying oven at 50°C for 10 h to obtain the demulsifier.

[0094] Test case

[0095] The performance of the demulsifiers prepared in Examples 1-8 and Comparative Examples 1-2 was tested:

[0096] The demulsifiers prepared in Examples 1-8 and Comparative Examples 1-2 were mixed with crushed stone with a continuous gradation of 5-15 mm particle size, natural fine sand with a fineness modulus of 2.2, S95 grade slag powder, and anionic emulsified asphalt at a mass ratio of 5:1500:250:200:1200 to obtain asphalt mixtures. The anionic emulsified asphalt was purchased from Shandong Fenglei New Material Technology Co., Ltd., with a total solids content ≥60% and grade 10#. 1900g of the asphalt mixture was placed in an unconfined compressive strength mold with a height of 120mm and a diameter of 100mm. A 6.55kg iron block was placed on the asphalt mixture for curing. After the curing time was reached, the mixture was demolded, and the compressive strength corresponding to different curing times was tested using a UTM universal testing machine. The loading rate of the UTM was 200mm / min. The test results are shown in Table 1.

[0097] Table 1

[0098]

[0099]

[0100] As shown in Table 1, the demulsifier prepared in this invention has a good demulsification effect, which can improve the demulsification speed of anionic emulsified asphalt. During the preparation of asphalt mixtures, it can effectively promote the adhesion between asphalt particles and aggregates such as crushed stone and natural fine sand, which helps to remove moisture from the asphalt mixture and accelerates the solidification and molding of the asphalt mixture. Comparing the compressive strength values ​​of asphalt mixtures with different curing times, when the compressive strength of the emulsified asphalt mixture reaches a certain value, the compressive strength tends to stabilize and no longer increases with increasing curing time; that is, this value is the maximum compressive strength, and the corresponding curing time is the demulsification time of the anionic emulsified asphalt. In this invention, the compressive strength of the asphalt mixture can reach its maximum value when the curing time is 4-5 hours, meaning the demulsification time of the demulsifier is 4-5 hours. The synergistic effect of the positive charges of the cations on the surface of clay minerals in the demulsifier and the quaternary ammonium salts formed can effectively change the double electric layer structure of the anionic emulsified asphalt surface, reduce the electrostatic repulsion between emulsified asphalt, achieve the demulsification effect, have a short demulsification time, and the asphalt particles after demulsification can effectively adhere to the aggregate, which helps to remove water from the asphalt mixture and accelerates the solidification and molding of the asphalt mixture. Compared with Example 1, in Comparative Example 1, because the montmorillonite was not acidified, it had fewer surface hydroxyl groups and lower reactivity with γ-methacryloxypropyltrimethoxysilane. The effective content of montmorillonite in the modified montmorillonite was low, the number of cations it carried was reduced, and the emulsifying performance was slightly reduced. The curing time of the asphalt mixture was increased, that is, the curing time for the asphalt mixture to reach the maximum compressive strength was extended to 6 hours. In Comparative Example 2, the demulsifier did not form a positively charged quaternary ammonium salt, which weakened its effect on changing the double electric layer structure of the anionic emulsified asphalt surface. In addition, the lipophilic long hydrocarbon chain introduced by hexadecane was missing, which reduced the amphiphilicity of the demulsifier and further weakened the demulsifying performance. The curing time for the asphalt mixture to reach the maximum compressive strength was significantly extended to 8 hours.

[0101] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a demulsifier, characterized in that, Includes the following steps: Step 1: Disperse the acidified clay mineral in xylene, add γ-methacryloxypropyltrimethoxysilane dropwise, and after the addition is complete, allow the reaction to proceed. After the reaction is complete, filter, wash, and dry to obtain the modified clay mineral. The mass ratio of the acidified clay mineral, xylene, and γ-methacryloxypropyltrimethoxysilane is 10:(100-150):(15-25), and the reaction conditions are 50-70℃ for 3-5 hours. The acidified clay mineral is prepared by the following steps: placing the clay mineral in an acid solution for impregnation. After impregnation, filter, wash, and dry to obtain the acidified clay mineral. The mass ratio of the clay mineral to the acid solution is 1:(5-10), and the impregnation conditions are 75-85℃ for 2-3 hours. The clay mineral includes montmorillonite, and the acid solution includes hydrochloric acid aqueous solution. Step 2: Disperse the modified clay mineral... The modified clay mineral was dispersed in N,N-dimethylformamide, and triethylenetetramine was added dropwise. After the addition was complete, the mixture was allowed to react. After the reaction was complete, the mixture was filtered, washed, and dried to obtain polytert-amine clay minerals. The mass ratio of the modified clay minerals, N,N-dimethylformamide, and triethylenetetramine was (25-35):(300-500):(1.5-2.5), and the reaction conditions were 20-30℃ for 18-36 h. Step 3: The polytert-amine clay minerals were dispersed in N,N-dimethylformamide, and hexadecane was added dropwise. After the addition was complete, the mixture was allowed to react. After the reaction was complete, the mixture was filtered, washed, and dried to obtain a demulsifier. The mass ratio of the polytert-amine clay minerals, N,N-dimethylformamide, and hexadecane was (26.5-37.5):(500-800):(18.5-31), and the reaction conditions were 80-120℃ for 6-8 h.

2. The method for preparing a demulsifier according to claim 1, characterized in that, The hydrochloric acid aqueous solution comprises a 10 wt% hydrochloric acid aqueous solution.

3. The application of a demulsifier prepared by the method of any one of claims 1-2 in asphalt mixtures.

Images