An ultrafine composite powder grinding aid and its preparation method

Abstract

This invention belongs to the technical field of building material admixtures, specifically relating to an ultrafine composite powder grinding aid, which is made from the following raw materials in parts by weight: 10-30 parts of polycarboxylic acid amine ester, 3-5 parts of aminated sulfonated lignin, 10-20 parts of inorganic dispersant, 5-15 parts of molasses, 5-10 parts of polyol, 0.5-1 parts of liquid alkali, and 30-60 parts of water. This invention also discloses a method for preparing the ultrafine composite powder grinding aid, comprising the following steps: S1: preparing aminated sulfonated lignin; S2: preparing polycarboxylic acid amine ester. This invention modifies lignin by aminated sulfonation and amine esterification to synthesize polycarboxylic acid amine ester, and then uses aminated sulfonated lignin and polycarboxylic acid amine ester as the main raw materials to formulate an ultrafine composite powder grinding aid. The prepared ultrafine composite powder admixture not only improves the grinding efficiency of ultrafine composite powder, reduces mill power consumption, and activates the activity of composite powder, but also achieves comprehensive utilization of lignin, fly ash, and mineral powder.

Description

Technical Field

[0001] This invention relates to the field of building material admixture processing, and more particularly to an ultrafine composite powder grinding aid and its preparation method. Background Technology

[0002] In 2022, my country's cement production reached 2.13 billion tons. The cement industry plays a vital role in the development of the construction industry, but it also brings many environmental problems, such as the consumption of natural resources and energy, and air pollution. Statistics show that the cement industry consumes approximately 5% of natural resources, uses 12% to 15% of total industrial energy, and emits about 6% of total carbon dioxide.

[0003] Fly ash, as the fine ash particles emitted during the combustion of fly ash as fuel, is rich in SiO2 and Al2O3. Using it as an auxiliary cementitious material can not only reduce costs and environmental pollution, but also improve the workability, mechanical properties, durability, and thermal properties of cement. Granulated blast furnace slag, a waste slag produced in steel plants during steelmaking, is rich in CaO, SiO2, and Al2O3. After grinding to a specific surface area greater than 400 m² / kg, slag exhibits a high activity index. Using it as an auxiliary cementitious material can not only improve the later-stage strength of cement, but also enhance concrete fluidity, reduce heat of hydration, improve corrosion resistance and impermeability, and reduce costs. A composite powder with a specific surface area, produced by grinding fly ash and slag powder in a certain proportion, is called ultrafine composite powder. Composite ultrafine powder products have excellent properties such as high fineness, high activity, and low water demand ratio. They are a high-functionality cement admixture and concrete admixture that can completely replace S95 mineral powder or partially replace cement, significantly reducing the production cost of cement and concrete, reducing permeability and improving durability, and improving the quality of cement and concrete products.

[0004] Improving the reactivity of fly ash and mineral powder is key to increasing their utilization rate. Mechanical grinding is an effective way to improve the reactivity of fly ash and mineral powder. Mechanical grinding can create defects on the particle surface during the grinding process, which can effectively increase the specific surface area of ​​the material and significantly improve the particle distribution. Generally, grinding stations first use a vertical roller mill to coarsely grind the composite powder, and then use a ball mill to finely grind the composite powder. However, mineral powder is glassy and has a high hardness, and its specific surface area is larger than that of cement. Therefore, compared with grinding cement materials, it is more difficult to produce slag powder from slag, with longer grinding time and higher power consumption. The large difference in grindability between fly ash and mineral powder and their good fluidity weaken the crushing capacity in the mill chamber. The fine fly ash powder acts as a cushion, and the excessively fast material flow rate greatly reduces its residence time in the mill, making the fly ash easy to grind but unable to be fully ground.

[0005] This invention provides an ultrafine composite powder grinding aid and its preparation method. By adding only a small amount or trace amount during the grinding process of the composite powder, the grinding efficiency of the composite powder can be greatly improved, enabling it to achieve a higher specific surface area and activity while reducing the energy consumption of the mill. Summary of the Invention

[0006] This invention first modifies an alkanolamine by esterification and uses it as a functional monomer to synthesize a polycarboxylic acid alkanolamine ester. Then, lignin is modified to obtain aminated sulfonated lignin. Subsequently, an ultrafine composite powder grinding aid is prepared by compounding the above-mentioned polycarboxylic acid alkanolamine ester, aminated sulfonated lignin, and components such as inorganic dispersants, molasses, and polyols. The prepared ultrafine composite powder grinding aid only needs to be added in small or trace amounts during the grinding process of the composite powder to improve the grinding efficiency, increase the specific surface area, fully utilize its potential activity, and reduce mill energy consumption.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0008] An ultrafine composite powder grinding aid is made from the following raw materials in parts by weight: 10-30 parts of polycarboxylic acid amine ester, 3-5 parts of aminated sulfonated lignin, 10-20 parts of inorganic dispersant, 5-15 parts of molasses, 5-10 parts of polyol, 0.5-1 parts of liquid alkali, and 30-60 parts of water.

[0009] As a preferred embodiment of the present invention, the method for preparing the polycarboxylic acid alcohol ester is as follows:

[0010] A1: Add 15 parts of alcoholic amine and 10 parts of maleic anhydride to a four-necked round-bottom reaction flask equipped with a constant temperature oil bath, electric stirrer, spherical condenser and temperature recorder, and stir at 130°C for 3 hours to obtain alcoholic amine ester.

[0011] A2: Add 100 parts of ethylene glycol monovinyl polyoxyethylene ether and deionized water to a four-necked flask equipped with an electric stirrer and a temperature recorder, and stir at room temperature until the polyoxyethylene ether is completely dissolved.

[0012] A3: Prepare dropping solutions A, B, and C. Dropping solution A consists of 10 parts unsaturated carboxylic acid, 15 parts alkanolamine ester, and deionized water; dropping solution B consists of 0.3 parts mercaptoethanol and deionized water; dropping solution C consists of 0.3 parts sodium dioctyl succinate sulfonate and deionized water.

[0013] A4: Add 0.2 parts of 30% hydrogen peroxide solution to a four-necked flask and stir for 5 minutes. Then, start adding solutions A, B, and C dropwise. Add solutions A and B dropwise over 50 minutes and solution C dropwise over 60 minutes. After the addition is complete, continue stirring at a constant temperature for 1 hour to obtain polycarboxylic acid alcohol ester.

[0014] As a preferred embodiment of the present invention, the method for preparing the aminated sulfonated lignin is as follows:

[0015] B1: Add 10 parts of purified lignin and 100 parts of distilled water to a four-necked round-bottom reaction flask equipped with a constant temperature water bath, electric stirrer, temperature recorder, dropping funnel, and spherical condenser, and stir thoroughly. Add liquid alkali to adjust the pH to 10, and then heat the system to 90°C.

[0016] B2: Add 10 parts of diethylenetriamine and 10 parts of formaldehyde to the flask, stir until fully reacted, and then cool to room temperature;

[0017] B3: Adjust the pH to 3 using hydrochloric acid solution, filter, and then wash with hydrochloric acid solution 3 times and distilled water 3 times respectively. Dry the product in a vacuum drying oven at 60°C to obtain aminated lignin.

[0018] B4: In a four-necked round-bottom reaction flask equipped with a constant temperature water bath, electric stirrer, temperature recorder, dropping funnel, and spherical condenser, add 5 parts of aminated lignin, 5 parts of sodium sulfate, and 100 parts of distilled water. Adjust the pH to 10 by adding liquid alkali. Heat the material in the flask to 70°C and stabilize for 5 minutes. Then, add 2 parts of formaldehyde dropwise over a period of 4 hours. Cool to room temperature and repeat the same steps as in B3 to obtain the final aminated sulfonated lignin.

[0019] A method for preparing an ultrafine composite powder grinding aid, the method specifically includes the following steps.

[0020] S1; Dissolve 3-5 parts of aminated sulfonated lignin and 0.5-1 parts of liquid alkali in 30-60 parts of water, and stir thoroughly until the lignin is completely dissolved;

[0021] S2: Add 10-20 parts of inorganic dispersant to the solution and stir thoroughly. After the inorganic dispersant is completely dissolved, add 20-30 parts of polycarboxylic acid amine ester, 5-15 parts of molasses, 5-10 parts of polyol, etc. in sequence and stir evenly to obtain ultrafine composite powder grinding aid.

[0022] As a preferred embodiment of the present invention, the polyol in S2 is one or more combinations of ethylene glycol, propylene glycol, diethylene glycol, and polymeric polyols.

[0023] The beneficial effects of this invention are:

[0024] This invention provides an ultrafine composite powder grinding aid and its preparation method. By modifying lignin and using it as a grinding aid raw material, the invention achieves comprehensive utilization, reducing the flow rate of the composite powder in the mill, increasing its residence time in the mill, and improving grinding efficiency. Through esterification modification of alkanolamines and free radical copolymerization, the grinding-aiding functional groups of the alkanolamines are combined into the polymer backbone, effectively realizing the synergistic effect of multiple organic functional groups. The synthesized polycarboxylic acid alkanolamine ester has the characteristics of low cost, good performance, and high comprehensive benefits, and has broad application prospects. The ultrafine composite powder grinding aid, formulated from aminated sulfonated lignin, polycarboxylic acid alkanolamine ester, molasses, polyols, and other raw materials, can greatly improve the grinding efficiency of composite powders, achieving higher specific surface area and activity while reducing mill energy consumption. Attached Figure Description

[0025] The above-mentioned features, characteristics, and advantages of the present invention, as well as their implementation methods, will become clearer and more readily understood in conjunction with the following description of the embodiments, which are illustrated in detail with reference to the accompanying drawings. Schematic diagrams are shown here:

[0026] Figure 1 This is a flowchart of a method for preparing an ultrafine composite powder grinding aid according to an embodiment of the present invention. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described below with reference to embodiments.

[0028] An ultrafine composite powder grinding aid is made from the following raw materials in parts by weight: 20-30 parts of polycarboxylic acid amine ester, 3-5 parts of aminated sulfonated lignin, 10-20 parts of inorganic dispersant, 5-15 parts of molasses, 5-10 parts of polyol, 0.5-1 parts of liquid alkali, and 30-60 parts of water.

[0029] In this embodiment, the polycarboxylic acid alcohol ester is prepared by the following steps:

[0030] A1: Add 15 parts of alcoholic amine and 10 parts of maleic anhydride to a four-necked round-bottom reaction flask equipped with a constant temperature oil bath, electric stirrer, spherical condenser and temperature recorder, and stir at 130°C for 3 hours to obtain alcoholic amine ester.

[0031] A2: Add 100 parts of ethylene glycol monovinyl polyoxyethylene ether and deionized water to a four-necked flask equipped with an electric stirrer and a temperature recorder, and stir at room temperature until the polyoxyethylene ether is completely dissolved.

[0032] A3: Prepare dropping solutions A, B, and C. Dropping solution A consists of 10 parts unsaturated carboxylic acid, 15 parts alkanolamine ester, and deionized water; dropping solution B consists of 0.3 parts mercaptoethanol and deionized water; dropping solution C consists of 0.3 parts sodium dioctyl succinate sulfonate and deionized water.

[0033] A4: Add 0.2 parts of 30% hydrogen peroxide solution to a four-necked flask and stir for 5 minutes. Then, start adding solutions A, B, and C dropwise. Add solutions A and B dropwise over 50 minutes and solution C dropwise over 60 minutes. After the addition is complete, continue stirring at a constant temperature for 1 hour to obtain polycarboxylic acid alcohol ester.

[0034] In this embodiment, the preparation of aminated sulfonated lignin is carried out through the following steps:

[0035] B1: Add 10 parts of purified lignin and 100 parts of distilled water to a four-necked round-bottom reaction flask equipped with a constant temperature water bath, electric stirrer, temperature recorder, dropping funnel, and spherical condenser, and stir thoroughly. Add liquid alkali to adjust the pH to 10, and then heat the system to 90°C.

[0036] B2: Add 10 parts of diethylenetriamine and 10 parts of formaldehyde to the flask, stir until fully reacted, and then cool to room temperature;

[0037] B3: Adjust the pH to 3 using hydrochloric acid solution, filter, and then wash with hydrochloric acid solution 3 times and distilled water 3 times respectively. Dry the product in a vacuum drying oven at 60°C to obtain aminated lignin.

[0038] B4: In a four-necked round-bottom reaction flask equipped with a constant temperature water bath, electric stirrer, temperature recorder, dropping funnel, and spherical condenser, add 5 parts of aminated lignin, 5 parts of sodium sulfate, and 100 parts of distilled water. Adjust the pH to 10 by adding liquid alkali. Heat the material in the flask to 70°C and stabilize for 5 minutes. Then, add 2 parts of formaldehyde dropwise over a period of 4 hours. Cool to room temperature and repeat the same steps as in B3 to obtain the final aminated sulfonated lignin.

[0039] The prepared polycarboxylic acid alcohol ester and aminated sulfonated lignin were used as raw materials to prepare an ultrafine composite powder grinding aid.

[0040] Example 1:

[0041] The preparation of an ultrafine composite powder grinding aid includes the following steps:

[0042] S1; Dissolve 3 parts of aminated sulfonated lignin and 1 part of liquid alkali in 41 parts of water, and stir thoroughly until the lignin is completely dissolved;

[0043] S2: Add 15 parts of inorganic dispersant to the solution and stir thoroughly. After the inorganic dispersant is completely dissolved, add 20 parts of polycarboxylic acid amine ester, 10 parts of molasses, 8 parts of polyol, etc. in sequence and stir evenly to obtain ultrafine composite powder grinding aid.

[0044] Example 2:

[0045] The preparation of the second ultrafine composite powder grinding aid includes the following steps:

[0046] S1; Dissolve 3 parts of aminated sulfonated lignin and 0.5 parts of liquid alkali in 56.5 parts of water, and stir thoroughly until the lignin is completely dissolved;

[0047] S2: Add 10 parts of inorganic dispersant to the solution and stir thoroughly. After the inorganic dispersant is completely dissolved, add 20 parts of polycarboxylic acid amine ester, 5 parts of molasses, 5 parts of polyol, etc. in sequence and stir evenly to obtain ultrafine composite powder grinding aid.

[0048] Example 3:

[0049] The preparation of ultrafine composite powder grinding aid includes the following steps:

[0050] S1; Dissolve 5 parts of aminated sulfonated lignin and 0.5 parts of liquid alkali in 34.5 parts of water, and stir thoroughly until the lignin is completely dissolved;

[0051] S2: Add 10 parts of inorganic dispersant to the solution and stir thoroughly. After the inorganic dispersant is completely dissolved, add 30 parts of polycarboxylic acid amine ester, 10 parts of molasses, 10 parts of polyol, etc. in sequence and stir evenly to obtain ultrafine composite powder grinding aid.

[0052] Example 4:

[0053] The preparation of ultrafine composite powder grinding aid, part four, includes the following steps.

[0054] S1; Dissolve 4 parts of aminated sulfonated lignin and 0.8 parts of liquid alkali in 37.2 parts of water, and stir thoroughly until the lignin is completely dissolved;

[0055] S2: Add 15 parts of inorganic dispersant to the solution and stir thoroughly. After the inorganic dispersant is completely dissolved, add 25 parts of polycarboxylic acid amine ester, 10 parts of molasses, 8 parts of polyol, etc. in sequence and stir evenly to obtain ultrafine composite powder grinding aid.

[0056] The obtained ultrafine composite powder grinding aids one, two, three, and four were added to an ST-500 uniform experimental mill at a weight ratio of 0.1 (ultrafine composite powder grinding aid): 100 (composite powder). The composite powder consisted of 60% fly ash and 40% mineral powder by weight. The grinding time was 45 minutes. Table 1 shows the performance test results of the ultrafine composite powder obtained without adding ultrafine composite powder grinding aids and with different ultrafine composite powder grinding aids.

[0057] Table 1. Performance test results of ultrafine composite powder obtained with and without ultrafine composite powder grinding aid.

[0058]

[0059] As shown in Table 1, by adding the ultrafine composite powder grinding aid of the present invention, only 1‰ of the composite powder by weight is required. After grinding for the same amount of time, the specific surface area of ​​the ultrafine composite powder is significantly increased, the residue on the 45μm sieve is significantly reduced, and the 7-day and 28-day activities of the ultrafine composite powder are increased by about 60%. The ultrafine composite powder grinding aid of the present invention can improve the grinding efficiency of composite powder, fully utilize the potential activity of ultrafine powder, and reduce mill energy consumption while realizing the comprehensive utilization of lignin, fly ash, and mineral powder.

[0060] Although the present invention has been disclosed above with reference to preferred embodiments, the embodiments are merely examples for illustrative purposes and are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. The scope of protection claimed by the present invention should be determined by the claims.

Claims

1. An ultrafine composite powder grinding aid, characterized in that: It is made from the following raw materials in parts by weight: 20-30 parts of polycarboxylic acid amine ester, 3-5 parts of aminated sulfonated lignin, 10-20 parts of inorganic dispersant, 5-15 parts of molasses, 5-10 parts of polyol, 0.5-1 part of liquid alkali, and 30-60 parts of water. The preparation method of the polycarboxylic acid alcohol amine ester is as follows: A1: Add 15 parts of alcoholic amine and 10 parts of maleic anhydride to a four-necked round-bottom reaction flask equipped with a constant temperature oil bath, electric stirrer, spherical condenser and temperature recorder, and stir at 130°C for 3 hours to obtain alcoholic amine ester. A2: Add 100 parts of ethylene glycol monovinyl polyoxyethylene ether and deionized water to a four-necked flask equipped with an electric stirrer and a temperature recorder, and stir at room temperature until the polyoxyethylene ether is completely dissolved. A3: Prepare dropping solution A, dropping solution B and dropping solution C; The drop solution A is composed of 10 parts unsaturated carboxylic acid, 15 parts alcohol ester and deionized water; Solution B consists of 0.3 parts mercaptoethanol and deionized water; The dropping solution C consists of 0.3 parts of sodium dioctyl succinate sulfonate and deionized water; A4: Add 0.2 parts of 30% hydrogen peroxide solution to a four-necked flask and stir for 5 minutes. Then start adding solutions A, B and C dropwise. Add solutions A and B dropwise over 50 minutes and solution C dropwise over 60 minutes. After the addition is complete, continue stirring at a constant temperature for 1 hour to obtain polycarboxylic acid alcohol ester. The preparation method of the aminated sulfonated lignin is as follows: B1: Add 10 parts of purified lignin and 100 parts of distilled water to a four-necked round-bottom reaction flask equipped with a constant temperature water bath, electric stirrer, temperature recorder, dropping funnel, and spherical condenser, and stir thoroughly. Add liquid alkali to adjust the pH to 10, and then heat the system to 90°C. B2: Add 10 parts of diethylenetriamine and 10 parts of formaldehyde to the flask, stir until fully reacted, and then cool to room temperature; B3: The pH was adjusted to 3 using hydrochloric acid solution, filtered, and then washed three times with hydrochloric acid solution and three times with distilled water. The lignin was dried in a vacuum drying oven at 60°C to obtain aminated lignin. B4: In a four-necked round-bottom reaction flask equipped with a constant temperature water bath, an electric stirrer, a temperature recorder, a dropping funnel, and a spherical condenser, 5 parts of aminated lignin, 5 parts of sodium sulfate, and 100 parts of distilled water are added. Liquid alkali is added to adjust the pH to 10. The material in the flask is heated to 70°C and stabilized for 5 minutes. Then, 2 parts of formaldehyde are added dropwise over a period of 4 hours. After cooling to room temperature, the same steps as in B3 are repeated to obtain the final aminated sulfonated lignin. The inorganic dispersant is one or more of sodium formate, sodium hexametaphosphate, sodium tripolyphosphate, sodium pyrophosphate, sodium thiocyanate, and sodium stearate. The polyol is one or more combinations of ethylene glycol, propylene glycol, diethylene glycol, and polymeric polyols; The preparation method of the ultrafine composite powder grinding aid specifically includes the following steps: S1; Dissolve 3-5 parts of aminated sulfonated lignin and 0.5-1 parts of liquid alkali in 30-60 parts of water, and stir thoroughly until the lignin is completely dissolved; S2: Add 10-20 parts of inorganic dispersant to the solution and stir thoroughly. After the inorganic dispersant is completely dissolved, add 20-30 parts of polycarboxylic acid amine ester, 5-15 parts of molasses, and 5-10 parts of polyol in sequence, and stir evenly to obtain ultrafine composite powder grinding aid.

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