Cement raw material grinding aid and preparation method thereof

Abstract

The invention provides a cement raw material grinding aid and a preparation method thereof. The preparation method comprises the following steps: by weight, 18-22% of a deep eutectic solvent, 20-30% of an industrial byproduct crude glycerine, 0.8-1.2% of a gemini type Gemini surfactant, 0.1-0.5% of nano cerium oxide, 1-3% of polyether modified polysiloxane, 5-10% of a carrier grafted with dimethylaminoethyl methacrylate and 30-50% of water, and the deep eutectic solvent is a hydrophobic DES system composed of tetrabutyl phosphine chloride and levulinic acid according to a molar ratio of 1: 3. Nano cerium oxide is subjected to freezing plasma grafting treatment, and the surface of the nano cerium oxide is coated with an acrylic polymer shell layer, the nano cerium oxide is treated in an argon environment of-50 DEG C in combination with a radio frequency plasma pulse mode, agglomeration and side reaction are avoided in a low-temperature inert atmosphere, grafting polymerization of acrylic monomers is promoted by plasmas, and grafting is uniform and efficient by controlling parameters; nitrogen protection aging enhances the modification firmness, and improves the dispersion stability and grinding aiding activity in an alkaline environment.

Description

Technical Field

[0001] The invention belongs to the field of cement raw meal grinding aids, in particular to a cement raw meal grinding aid and a preparation method thereof. Background Art

[0002] Cement raw meal grinding aid is an additive added during the cement raw meal grinding process. It can improve the grinding effect and increase the grinding efficiency. It is usually composed of a variety of chemical substances.

[0003] For example, publication number CN115196904B, the cement raw meal grinding aid and its preparation method can accelerate the reaction speed of raw meal particles during clinker firing, improve the degree of reaction completion, improve the production speed and quality of clinker, and reduce energy consumption, thereby achieving quality improvement and energy saving. However, its raw material selection is relatively conventional, the role of sodium carbonate in regulating the liquid phase amount is relatively single, and when faced with complex raw meal components, the dispersion effect and the role of promoting the reaction are limited. The preparation method is also relatively simple, and it is difficult to give full play to the synergistic effect of each component, and it is impossible to effectively improve the grinding aid effect and clinker quality.

[0004] Therefore, in view of this, a cement raw meal grinding aid and a preparation method thereof are proposed. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a cement raw meal grinding aid and a preparation method thereof, which are used to solve the problems raised in the background technology.

[0006] A cement raw meal grinding aid, comprising the following raw materials in percentage by weight:

[0007] 18-22% of low eutectic solvent, 20-30% of industrial by-product crude glycerol, 0.8-1.2% of Gemini surfactant, 0.1-0.5% of nano-cerium oxide, 1-3% of polyether-modified polysiloxane, 5-10% of carrier grafted with dimethylaminoethyl methacrylate, and 30-50% of water.

[0008] Preferably, the deep eutectic solvent is a hydrophobic DES system composed of tetrabutylphosphine chloride and levulinic acid in a molar ratio of 1:3, and the contact angle is ≥110°.

[0009] Preferably, the nano-cerium oxide is treated by cryo-plasma grafting, and its surface is coated with an acrylic polymer shell layer, with a Zeta potential of ≤-45 mV and a particle size distribution of 5±0.8 nm.

[0010] Preferably, the Gemini surfactant and perfluoropolyether are co-encapsulated in aerosol microcapsules synthesized by supercritical CO2, the microcapsule particle size is 1-3 μm, and the rupture temperature is 80±5°C.

[0011] The preparation method of the above-mentioned cement raw meal grinding aid comprises the following preparation steps:

[0012] Nano-cerium oxide pretreatment S1: In an argon environment at -50 ° C, nano-CeO2 was mixed with 5 wt% acrylic acid / methanol solution, subjected to 13.56 MHz radio frequency plasma treatment for 30 min, and then heated to -20 ° C under nitrogen protection and aged for 2 h;

[0013] DES-crude glycerol co-solvent system construction S2: Tetrabutylphosphine chloride and levulinic acid were stirred and dissolved at 60°C in a molar ratio of 1:3, industrial crude glycerol purified by molecular distillation was added, and after degassing under a vacuum of 2 kPa, supercritical CO2 was injected to 15 MPa;

[0014] In situ synthesis of microcapsules S3: Gemini surfactant and PFPE were mixed in a mass ratio of 2:1, turbulently stirred in a 25 MPa supercritical CO2 environment, and then rapidly depressurized through a coaxial atomizing nozzle to produce 1.2 ± 0.3 μm microcapsules;

[0015] Multiphase system composite S4: pretreated nano-CeO2, DES-glycerol system, microcapsules and grafted DMAEMA carrier were added to a high-pressure homogenizer and circulated at 120°C and 50 MPa for 5 times;

[0016] Aqueous system stabilization S5: Deionized water was added to the composite system in stages, and 40 kHz ultrasonic vibration was applied at intervals of 3 minutes between each stage, and the final pH was adjusted to 9.0-9.5.

[0017] Preferably, the plasma treatment in step S1 adopts a pulse mode with a duty cycle of 1:5, a pulse frequency of 10 kHz, and an acrylic acid monomer flux rate of 0.2 mL / min.

[0018] Preferably, the phase change rate of supercritical CO2 in step S3 is 50 MPa / s, the inner diameter of the coaxial atomizing nozzle is 0.15 mm, the outer diameter is 0.35 mm, and the gas-liquid ratio is 15:1.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. During use, the present invention treats nano-cerium oxide in an argon environment at -50°C in combination with a radio frequency plasma pulse mode. The low-temperature inert atmosphere avoids agglomeration and side reactions, and the plasma promotes the graft polymerization of acrylic acid monomers. The parameters are controlled to ensure uniform and efficient grafting. Nitrogen protection and aging enhance the modified firmness and improve its dispersion stability and grinding aid activity in an alkaline environment.

[0021] 2. In the present invention, tetrabutylphosphine chloride and levulinic acid are dissolved in a specific ratio at 60°C to form a hydrophobic DES system to improve the interface. Purified industrial crude glycerol is added, degassed, and then injected into a supercritical fluid. The supercritical properties allow the DES and crude glycerol to be fully mixed, maintaining pressure to promote molecular interaction, and creating compatible and synergistic conditions for subsequent compounding.

[0022] 3. During use, the present invention involves turbulent stirring of Gemini surfactant and PFPE in a supercritical environment at a specific ratio, and rapid pressure relief through a coaxial atomizing nozzle to generate microcapsules. The supercritical state facilitates mixing, turbulence intensifies the effect, and the phase change rate and nozzle parameters are precisely controlled, so that the microcapsule particle size can rupture at a suitable temperature to function. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a line graph showing how the grinding efficiency improvement ratio of the present invention changes with the effect observation time;

[0024] Figure 2 It is a line graph showing the change in the increase in compressive strength of the present invention as a function of the effect observation time (days);

[0025] Figure 3 It is a line graph showing the change in the cement raw material production rate per unit time versus the unit observation time (h) of the present invention;

[0026] Figure 4 is a line graph showing the change in viscosity of the system of the present invention with unit observation time (h);

[0027] Figure 5 It is a line graph showing the biodegradation rate of the present invention changing with unit observation time (h). DETAILED DESCRIPTION

[0028] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0029] A cement raw meal grinding aid, comprising the following raw materials in percentage by weight:

[0030] Deep eutectic solvent 18-22%, industrial by-product crude glycerin 20-30%, Gemini surfactant 0.8-1.2%, nano cerium oxide 0.1-0.5%, polyether modified polysiloxane 1-3%, grafted dimethylaminoethyl methacrylate carrier 5-10%, water 30-50%,

[0031] Specifically, the deep eutectic solvent is a hydrophobic DES system composed of tetrabutylphosphine chloride and levulinic acid in a molar ratio of 1:3. This DES system has unique hydrophobic properties and a contact angle of ≥110°. It can effectively improve the interparticle interface properties during the cement raw material grinding process, reduce particle agglomeration, promote material dispersion, and create favorable conditions for the subsequent functioning of other components of the grinding aid. The DES system accounts for 18-22% of the grinding aid. This ratio has been verified by numerous experiments to fully utilize its interface regulation advantages within this range while ensuring optimal synergy with other components.

[0032] Industrial by-product crude glycerin is purified by molecular distillation. Crude glycerin, a by-product of biodiesel, comes from a wide range of sources but contains a high level of impurities, especially methanol residues and saponification products. Molecular distillation is used to remove most of these impurities, reducing the methanol content to a level that meets environmental standards (GB31573-2015 emission standards). It accounts for 20-30% of the grinding aid, acting as a solvent to promote uniform mixing of the various components. It also participates in some physical and chemical reactions during the grinding process, enhancing the grinding effect. This effectively utilizes industrial solid waste and reduces production costs.

[0033] Gemini surfactants are co-encapsulated with perfluoropolyether in supercritical fluid aerosol microcapsules. Compared to traditional surfactants, Gemini surfactants have a lower critical micelle concentration and can more effectively reduce surface tension. They are encapsulated in microcapsules with PFPE. The microcapsules have a particle size of 1-3μm and a rupture temperature of 80±5°C, allowing them to be released during the grinding process. When the temperature reaches around 80°C, the microcapsules rupture, and the released surfactants and PFPE quickly take effect, reducing the surface energy of the particles and inhibiting foam generation. Gemini surfactants account for 0.8-1.2% of the grinding aid, which is a small proportion but plays a key role.

[0034] Nano-cerium oxide is treated with cryo-plasma grafting and coated with an acrylic polymer shell. The zeta potential is ≤-45mV and the particle size distribution is 5±0.8nm. After this special treatment, nano-cerium oxide can maintain good dispersion stability in the alkaline environment of cement raw materials. The carboxylic acid groups on its surface can interact with other components. Nano-cerium oxide can use its surface oxygen vacancies to catalyze the breakage of SiO2 covalent bonds, reducing grinding energy consumption. It accounts for 0.1-0.5% of the grinding aid, and a small amount of addition can significantly improve grinding efficiency.

[0035] Polyether-modified polysiloxane accounts for 1-3% of the grinding aid. As a special additive, it works synergistically with Gemini surfactants to further optimize the defoaming performance and surface activity of the grinding aid, ensuring a stable grinding process.

[0036] The carrier of grafted dimethylaminoethyl methacrylate accounts for 5-10%. This carrier enables the grinding aid to quickly release active ingredients in the initial grinding stage (pH>10) and automatically passivate during the cement hydration stage (pH<12.5), avoiding adverse effects on the later strength of the cement and effectively balancing the effects of the grinding aid at different stages.

[0037] Water is used as a solvent, accounting for 30-50%, so that the components are fully mixed to form a uniform and stable grinding aid system.

[0038] A method for preparing a cement raw meal grinding aid comprises the following steps:

[0039] Nano-cerium oxide pretreatment S1: In an argon environment at -50 ° C, nano-CeO2 was mixed with 5 wt% acrylic acid / methanol solution, subjected to 13.56 MHz radio frequency plasma treatment for 30 min, and then heated to -20 ° C under nitrogen protection and aged for 2 h;

[0040] The operation is carried out in an argon atmosphere at -50°C to create a low-temperature, inert atmosphere. The low temperature slows the reaction rate, making the subsequent plasma treatment process more controllable and preventing the agglomeration of nano-cerium oxide or unnecessary side reactions with other substances caused by excessive temperatures. As an inert gas, argon can effectively isolate oxygen and water vapor, preventing the nano-cerium oxide from oxidation or moisture, ensuring its original performance stability.

[0041] Nano-cerium oxide is mixed with 5wt% acrylic acid / methanol solution. The acrylic acid monomer has good dispersibility in the methanol solution and can fully surround the nano-cerium oxide particles. Subsequently, 13.56MHz radio frequency plasma treatment is applied for 30 minutes. The high-energy electrons, ions and free radicals generated by the plasma can promote the grafting polymerization of acrylic acid monomer on the surface of nano-cerium oxide. In this process, a pulse mode with a duty cycle of 1:5, a pulse frequency of 10kHz and an acrylic acid monomer flux rate of 0.2mL / min is adopted. This precise control can make the grafting reaction more uniform and efficient, so that the acrylic acid polymer shell is evenly coated on the surface of nano-cerium oxide. After the treatment, the temperature is raised to -20℃ under nitrogen protection and aged for 2h. Nitrogen further protects the reaction product. The aging process helps to further grow and stabilize the grafted polymer chain, making the surface modification effect of nano-cerium oxide more solid, laying a solid foundation for its subsequent role in the grinding aid system.

[0042] DES-crude glycerol co-solvent system construction S2: Tetrabutylphosphine chloride and levulinic acid were stirred and dissolved at 60°C in a molar ratio of 1:3, industrial crude glycerol purified by molecular distillation was added, and after degassing under a vacuum of 2 kPa, supercritical CO2 was injected to 15 MPa;

[0043] Tetrabutylphosphine chloride and levulinic acid were stirred and dissolved at 60°C in a molar ratio of 1:3. This temperature ensures the dissolution rate of the two substances while preventing their decomposition or other adverse reactions due to excessive temperature. The hydrophobic DES system formed at this ratio has a contact angle of ≥110°, which can significantly improve the interfacial interaction with cement raw material particles.

[0044] Industrial crude glycerol purified by molecular distillation is added. Molecular distillation can effectively remove impurities such as methanol and saponification in crude glycerol, reduce their adverse effects on the performance of cement raw material grinding aids, and realize the resource utilization of industrial solid waste. Degassing is carried out under a vacuum of 2kPa to remove air and volatile impurities in the system to avoid affecting the subsequent supercritical CO2 injection effect and the stability of the entire system. Supercritical CO2 is injected to 15MPa. Supercritical CO2 has good diffusivity and solubility, which can make DES and crude glycerol fully mixed and penetrate into each other's molecular gaps to form a uniform and stable co-solvent system. Maintaining this pressure for a period of time can ensure that the molecules in the system fully interact with each other, creating favorable conditions for compatibility and synergy when subsequently compounded with other components.

[0045] In situ synthesis of microcapsules S3: Gemini surfactant and PFPE were mixed in a mass ratio of 2:1, turbulently stirred in a 25 MPa supercritical CO2 environment, and then rapidly depressurized through a coaxial atomizing nozzle to produce 1.2 ± 0.3 μm microcapsules;

[0046] Among them, Gemini surfactant and PFPE are mixed in a mass ratio of 2:1. Gemini surfactant has a unique molecular structure and can reduce surface tension more efficiently than traditional surfactants. When mixed with PFPE in a specific ratio, the synergistic advantages of the two can be brought into play. Turbulent stirring in a 25MPa supercritical environment causes significant changes in the physical and chemical properties of the substance in the supercritical state, with an increase in the diffusion coefficient and a decrease in viscosity, which is conducive to the full mixing and uniform dispersion of the two substances. Turbulent stirring further enhances the mixing effect and makes the collisions between molecules more frequent.

[0047] The coaxial atomizing nozzle is used to quickly release pressure to generate 1.2±0.3μm microcapsules. The phase change rate of supercritical CO2 is 50MPa / s. The inner diameter of the coaxial atomizing nozzle is 0.15mm, the outer diameter is 0.35mm, and the gas-liquid ratio is 15:1. Under such precisely controlled conditions, the solvent in the mixed solution evaporates rapidly during the instantaneous pressure reduction process. The Gemini surfactant and PFPE form a stable microcapsule structure under the action of interfacial tension. The precisely controlled particle size ensures that the microcapsules rupture at the appropriate temperature (80±5℃) during the cement raw material grinding process, releasing the internal surfactant and PFPE, thereby effectively reducing surface energy and inhibiting foam generation.

[0048] Multiphase system composite S4: pretreated nano-CeO2, DES-glycerol system, microcapsules and grafted DMAEMA carrier were added to a high-pressure homogenizer and circulated at 120°C and 50 MPa for 5 times;

[0049] Among them, pretreated nano-cerium oxide, DES-glycerol system, microcapsules and grafted DMAEMA carriers are added to a high-pressure homogenizer. The high-pressure homogenizer can provide strong shear force and pressure. The treatment is circulated 5 times at 120°C and 50MPa. The high temperature helps promote the thermal motion of molecules and enhance the interaction between the phases. The high pressure can make the substances in different phases fully mixed under strong pressure. Nano-cerium oxide is evenly dispersed in the DES-glycerol system, and the microcapsules can also be stably distributed therein. The grafted DMAEMA carrier is intertwined with other components. The treatment is circulated 5 times to ensure that each treatment can make the system more uniform and the interaction between the components more sufficient. After multiple treatments, a stable multi-phase composite system is formed, and the synergistic effect of the components is maximized, providing a guarantee for the performance of the cement raw meal grinding aid.

[0050] Aqueous system stabilization S5: Deionized water was added to the composite system in stages, and 40 kHz ultrasonic vibration was applied at intervals of 3 minutes between each stage, and the final pH was adjusted to 9.0-9.5.

[0051] Among them, deionized water is added to the composite system in stages. The staged addition can fully mix the water with the composite system, avoiding the uneven local concentration of the system or phase separation caused by adding a large amount of water at one time. 40kHz ultrasonic vibration is applied at an interval of 3 minutes in each stage. The cavitation effect of the ultrasound can further promote the mixing of water and other components in the system, and at the same time help to break up possible agglomerates to make the system more uniform. During the process of adding water and ultrasonic vibration, the pH value of the system will change. By adjusting the final pH to 9.0-9.5, within this pH range, the components in the grinding aid can maintain a stable chemical state, which is beneficial for each component to exert its own grinding aid effect, and can also ensure the stability of the entire aqueous system, and prevent the decomposition or precipitation of certain components due to improper pH value, thereby obtaining a cement raw meal grinding aid product with excellent performance, stability and reliability.

[0052] Example 1:

[0053] The above-described procedure and generalized starting materials were used.

[0054] (1) Raw material preparation

[0055] Deep eutectic solvent: A common commercially available DES is selected, with no specific restrictions on the specific composition, accounting for 20%.

[0056] Industrial by-product crude glycerin: Ordinary industrial by-product crude glycerin from a biodiesel plant, without special purification treatment, accounts for 25%.

[0057] Gemini surfactants: Commonly available Gemini surfactants, accounting for 1%.

[0058] Nano-cerium oxide: Ordinary commercially available nano-cerium oxide, without special treatment, accounts for 0.3%.

[0059] Polyether modified polysiloxane: conventional polyether modified polysiloxane products, accounting for 2%.

[0060] Carrier grafted with dimethylaminoethyl methacrylate: self-synthesized grafted DMAEMA carrier, accounting for 8%.

[0061] Water: Ordinary deionized water, accounting for 43.7%.

[0062] (2) Preparation steps

[0063] Nano-cerium oxide pretreatment S1:

[0064] Nano-cerium oxide was mixed with 5 wt% acrylic acid / methanol solution at -50°C in an argon atmosphere and treated with 13.56 MHz radio frequency plasma for 30 min.

[0065] Then, the temperature was raised to -20°C under nitrogen protection and aged for 2 hours. The plasma treatment adopted a pulse mode with a duty cycle of 1:5, a pulse frequency of 10 kHz, and an acrylic acid monomer flux rate of 0.2 mL / min.

[0066] DES-crude glycerol co-solvent system construction S2:

[0067] The selected DES was stirred and dissolved at 60°C, and crude glycerin, a by-product of ordinary industry, was added. After degassing under a vacuum of 2kPa, supercritical CO2 was injected to 15MPa.

[0068] In situ synthesis of microcapsules S3:

[0069] Gemini surfactant and PFPE were mixed in a mass ratio of 2:1, turbulently stirred in a 25MPa supercritical CO2 environment, and then rapidly depressurized through a coaxial atomizing nozzle to produce microcapsules.

[0070] The phase change rate of supercritical CO2 is 50 MPa / s, the inner diameter of the coaxial atomizing nozzle is 0.15 mm, the outer diameter is 0.35 mm, and the gas-liquid ratio is 15:1.

[0071] Multiphase system composite S4:

[0072] The pretreated nano-cerium oxide, DES-glycerol system, microcapsules and grafted DMAEMA carrier were added into a high-pressure homogenizer and circulated for 5 times at 120°C and 50 MPa.

[0073] Aqueous system stabilization S5:

[0074] Deionized water was added to the composite system in stages at a uniform rate, and 40kHz ultrasonic vibration was applied every 3 minutes to promote mixing by means of ultrasonic cavitation effect. The final pH was adjusted to 9.0-9.5 to ensure the stability of the system.

[0075] Table 1: Preparation parameters of cement raw meal grinding aids for specific steps and general raw materials

[0076]

[0077] Example 2: Using the above raw materials and general steps

[0078] (1) Raw material preparation

[0079] Deep eutectic solvent: a hydrophobic DES system composed of tetrabutylphosphine chloride and levulinic acid in a molar ratio of 1:3, accounting for 20%.

[0080] Industrial by-product crude glycerin: Industrial crude glycerin purified by molecular distillation accounts for 25%.

[0081] Gemini surfactants: Gemini surfactants co-encapsulated with perfluoropolyether in supercritical synthetic aerosol microcapsules, accounting for 1%.

[0082] Nano-cerium oxide: After cryo-plasma grafting treatment, the surface is coated with an acrylic polymer shell, the Zeta potential is ≤-45mV, and the particle size distribution is 5±0.8nm, accounting for 0.3%.

[0083] Polyether modified polysiloxane: 2%

[0084] Carrier grafted with dimethylaminoethyl methacrylate: 8%.

[0085] Water: Deionized water, accounting for 43.7%.

[0086] (2) Preparation steps

[0087] Nano-cerium oxide pretreatment S1:

[0088] At -50°C, nano-cerium oxide was simply mixed with a 5 wt% acrylic acid / methanol solution, stirred for 30 minutes, and then heated to -20°C for aging for 2 hours.

[0089] DES-crude glycerol co-solvent system construction S2:

[0090] Tetrabutylphosphine chloride and levulinic acid were stirred and dissolved at 60° C. in a molar ratio of 1:3, and industrial crude glycerol purified by molecular distillation was added and briefly stirred to uniformity.

[0091] In situ synthesis of microcapsules S3:

[0092] The Gemini surfactant and PFPE were mixed in a mass ratio of 2:1, stirred conventionally, and then sprayed through a common nozzle to prepare microcapsules.

[0093] Multiphase system composite S4:

[0094] The pretreated nano-cerium oxide, the DES-glycerol system, the microcapsules and the grafted DMAEMA carrier are mixed uniformly in a common stirring device.

[0095] Aqueous system stabilization S5:

[0096] Deionized water was added to the composite system at once, stirred briefly, and the pH was adjusted to 9.0-9.5.

[0097] Table 2: Preparation parameters of cement raw meal grinding aids for specific raw materials and general steps

[0098]

[0099] Example 3: Using the above steps and the above raw materials

[0100] (1) Raw material preparation

[0101] Deep eutectic solvent: a hydrophobic DES system composed of tetrabutylphosphine chloride and levulinic acid in a molar ratio of 1:3, accounting for 20%.

[0102] Industrial by-product crude glycerin: Industrial crude glycerin purified by molecular distillation accounts for 25%.

[0103] Gemini surfactants: Gemini surfactants co-encapsulated with perfluoropolyether in supercritical synthetic aerosol microcapsules, accounting for 1%.

[0104] Nano-cerium oxide: After cryo-plasma grafting treatment, the surface is coated with an acrylic polymer shell, the Zeta potential is ≤-45mV, and the particle size distribution is 5±0.8nm, accounting for 0.3%.

[0105] Polyether modified polysiloxane: 2%

[0106] Carrier grafted with dimethylaminoethyl methacrylate: 8%.

[0107] Water: Deionized water, accounting for 43.7%.

[0108] (2) Preparation steps

[0109] Nano-cerium oxide pretreatment S1:

[0110] Nano-cerium oxide was mixed with a 5wt% acrylic acid / methanol solution at -50°C under argon and treated with a 13.56MHz radiofrequency plasma for 30 minutes. The mixture was then heated to -20°C under nitrogen and aged for 2 hours. The plasma treatment was performed in pulsed mode with a duty cycle of 1:5, a pulse frequency of 10kHz, and an acrylic acid monomer flux rate of 0.2mL / min.

[0111] DES-crude glycerol co-solvent system construction S2:

[0112] Tetrabutylphosphine chloride and levulinic acid were stirred and dissolved at 60°C in a molar ratio of 1:3, industrial crude glycerol purified by molecular distillation was added, and after degassing under a vacuum of 2 kPa, supercritical CO2 was injected to 15 MPa.

[0113] In situ synthesis of microcapsules S3:

[0114] Gemini surfactant and PFPE were mixed in a 2:1 mass ratio and turbulently stirred in a 25 MPa supercritical CO2 environment before being rapidly depressurized through a coaxial atomizing nozzle to produce microcapsules with a size of 1.2 ± 0.3 μm. The supercritical CO2 phase transition rate was 50 MPa / s. The coaxial atomizing nozzle had an inner diameter of 0.15 mm, an outer diameter of 0.35 mm, and a gas-to-liquid ratio of 15:1.

[0115] Multiphase system composite S4:

[0116] The pretreated nano-cerium oxide, DES-glycerol system, microcapsules and grafted DMAEMA carrier were added into a high-pressure homogenizer and circulated for 5 times at 120°C and 50 MPa.

[0117] Aqueous system stabilization S5:

[0118] Deionized water was added to the composite system in stages, and 40 kHz ultrasonic vibration was applied at intervals of 3 minutes in each stage. The final pH was adjusted to 9.0-9.5.

[0119] Table 3: Preparation parameters of cement raw material grinding aids for Example 3 steps and raw materials

[0120]

[0121] Example 4: General raw materials and general steps

[0122] (1) Raw material preparation

[0123] Deep eutectic solvent: Common commercially available DES, accounting for 20%.

[0124] Industrial by-product crude glycerin: Ordinary industrial by-product crude glycerin, unpurified, accounts for 25%.

[0125] Gemini surfactant: a common commercially available product, not encapsulated, accounting for 1%.

[0126] Nano-cerium oxide: Ordinary commercially available nano-cerium oxide, untreated, accounting for 0.3%.

[0127] Polyether modified polysiloxane: common product, accounting for 2%.

[0128] Carrier grafted with dimethylaminoethyl methacrylate: a carrier simply synthesized by ourselves, accounting for 8%.

[0129] Water: Ordinary tap water, accounting for 43.7%.

[0130] (2) Preparation steps

[0131] Nano-cerium oxide pretreatment S1:

[0132] At room temperature, nano-cerium oxide was mixed with 5 wt % acrylic acid / methanol solution and stirred briefly for 30 minutes.

[0133] DES-crude glycerol co-solvent system construction S2:

[0134] Dissolve ordinary DES and ordinary industrial by-product crude glycerol at 60°C with stirring and mix them evenly.

[0135] In situ synthesis of microcapsules S3:

[0136] The Gemini surfactant and PFPE were mixed in a mass ratio of 2:1, stirred briefly, and then added dropwise through an ordinary dropper to prepare microcapsules.

[0137] Multiphase system composite S4:

[0138] The pretreated nano-cerium oxide, DES-glycerol system, microcapsules and grafted DMAEMA carrier were stirred and mixed in a common stirrer.

[0139] Aqueous system stabilization S5:

[0140] Add tap water to the composite system at once, stir briefly, and adjust the pH to 9.0-9.5.

[0141] Table 4: Preparation parameters of cement raw material grinding aids using common raw materials and common steps

[0142]

[0143] Through the above four examples, different combinations were tried from two key dimensions: raw material selection and preparation steps. Example 1 used specific steps to process general raw materials, attempting to explore the potential of the process to improve the performance of conventional materials. Example 2 used specific raw materials with general steps to observe the performance of raw material properties under conventional preparation processes.

[0144] Example 3 is a combination of specific steps and specific raw materials, aiming to maximize the advantages of both. Example 4 is a combination of general raw materials and general steps, serving as a basic reference.

[0145] In practical applications, the performance of cement raw meal grinding aids directly impacts the cost, efficiency, and quality of cement production. To more intuitively and comprehensively compare the performance differences between the grinding aids in each example, as well as their differences with conventional comparative examples, key data has been summarized in the following table comparing multiple cement raw meal grinding aid solutions.

[0146] The table also covers core performance indicators such as grinding efficiency improvement ratio, 28-day compressive strength increase, foam half-life, system viscosity, and biodegradation rate;

[0147] At the same time, data from two comparative examples are also included. Through these data, we can clearly see the impact of different combinations of raw materials and preparation steps on the performance of cement raw meal grinding aids, providing a strong basis for further optimizing the grinding aid formula and process, and then on this basis, we can determine the direction of technical improvement and provide technical support for the research and development of cement raw meal grinding aids with better performance.

[0148] Table 5: Comparison of multiple solutions for cement raw meal grinding aids

[0149]

[0150]

[0151] In terms of cost control and the effect of increasing cement raw meal production per unit time, each example exhibited significant differences from the comparative example, with Example 3 exhibiting the most superior properties in both respects. Accurate calculations show that the grinding aid prepared in Example 3 can cost as little as 3.8 yuan per ton, offering a significant cost advantage over other solutions. Furthermore, the use of the cement raw meal grinding aid in Example 3 increased cement raw meal production per unit time by 20%, significantly improving production efficiency.

[0152] The first and second embodiments are at a medium level. The grinding aid cost per ton of the first embodiment is RMB 4.2, and the cement raw material output per unit time is increased by 15%. The grinding aid cost per ton of the second embodiment is RMB 4.5, and the cement raw material output per unit time is increased by 10%.

[0153] On the other hand, Example 4 and Comparative Example 2 have poor cost control and output improvement effects. The grinding aid cost per ton of Example 4 is as high as RMB 5.0, while the cement raw material output per unit time is only increased by 5%. The grinding aid cost per ton of Comparative Example 2 is RMB 5.5, and the output improvement ratio is only 3%. Comparative Example 1 is in an intermediate state in terms of cost and efficiency, with a grinding aid cost per ton of RMB 4.8 and an 8% increase in cement raw material output per unit time.

[0154] Among them, cement quality is one of the key indicators for measuring the performance of cement raw meal grinding aids. In terms of cement flexural strength and standard consistency water requirement, each solution performed differently. The cement prepared in Example 3 showed the most excellent quality characteristics. Its cement flexural strength reached 5.2 MPa after 3 days and 8.0 MPa after 28 days, which were the highest values ​​among all solutions. At the same time, the standard consistency water requirement of cement was reduced by 4%, which has positive significance for improving the construction performance of cement and enhancing the quality of cement products.

[0155] The quality of the cements of Example 1 and Example 2 is within a reasonable range. The 3-day flexural strength of the cement of Example 1 is 4.8 MPa, the 28-day flexural strength is 7.5 MPa, and the standard consistency water requirement is reduced by 3%. The 3-day flexural strength of the cement of Example 2 is 4.5 MPa, the 28-day flexural strength is 7.2 MPa, and the standard consistency water requirement is reduced by 2%.

[0156] The cement quality of Example 4 and Comparative Example 2 is relatively low. The 3-day flexural strength of the cement of Example 4 is 4.2 MPa, the 28-day flexural strength is 6.8 MPa, and the standard consistency water requirement is unchanged; the 3-day flexural strength of the cement of Comparative Example 2 is 4.0 MPa, the 28-day flexural strength is 6.5 MPa, and the standard consistency water requirement increases by 2%. The quality of the cement of Comparative Example 1 is average, with a 3-day flexural strength of 4.6 MPa, a 28-day flexural strength of 7.0 MPa, and a standard consistency water requirement reduced by 1%.

[0157] In addition, from the perspective of environmental protection, the heavy metal content of the grinding aid of each embodiment is at a relatively low level, meeting relevant environmental protection requirements. Specifically, the lead content of the grinding aid in Examples 1, 2, 3 and 4 is all less than 1mg / kg, and mercury content is all less than 0.1mg / kg, and cadmium content is all less than 0.5mg / kg. Although the heavy metal content of Comparative Example 1 and Comparative Example 2 is slightly higher than that of the embodiment, it is still within an acceptable range. In Comparative Example 1, lead content is less than 2mg / kg, mercury content is less than 0.2mg / kg, and cadmium content is less than 1mg / kg. In Comparative Example 2, lead content is less than 3mg / kg, mercury content is less than 0.3mg / kg, and cadmium content is less than 1.5mg / kg. By comparison, the embodiment has obvious advantages in terms of environmental performance, comprehensive cost, efficiency, cement quality and practical parameters such as environmental protection, and embodiment three is the most outstanding in the comparison of multiple schemes.

[0158] The five parameter variables in the above embodiment: grinding efficiency improvement ratio, 28-day compressive strength increase value, cement raw material unit time output improvement ratio, system viscosity and biodegradation rate, as well as the changes in the values ​​in the four embodiments and two comparative examples are obtained from the following five parameter variables. Figure 1 To the attached Figure 5 The present invention utilizes a specific hydrophobic DES system, industrial crude glycerol purified by molecular distillation, Gemini surfactants encapsulated in supercritical synthetic aerosol microcapsules, and nano-cerium oxide grafted by cryopreservation plasma. These ingredients work synergistically, providing insights and methods for improving the performance of grinding aids. The preparation process involves pre-treating the nano-cerium oxide in a low-temperature argon environment, supercritically constructing a DES-crude glycerol co-solvent system, and in-situ microcapsule synthesis. These processes control the reaction conditions to ensure the optimal performance of each ingredient, representing a breakthrough in traditional grinding aid preparation methods.

[0159] And the line graph data shows that Example 3 adopts this formula and step, and is superior to other embodiments and comparative examples in performance indicators such as grinding efficiency improvement ratio, 28-day compressive strength added value, and cement raw material unit time output improvement ratio, thereby improving cement production efficiency and quality. At the same time, the system viscosity is controlled, and the biodegradation rate meets the requirements, taking into account production stability and environmental protection. In addition, the cost of Example 3 tons of grinding aid is 3.8 yuan, achieving performance and cost balance, with economic and environmental benefits, and has promotion prospects in cement production practical applications, proving that the formula and preparation steps of the present invention possess substantial characteristics and progress.

[0160] All aspects of the present invention are within the scope of protection of this patent.

[0161] The embodiments of the present invention are provided for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A cement raw meal grinding aid, characterized in that: The raw materials include the following weight percentages: 18-22% of low eutectic solvent, 20-30% of industrial by-product crude glycerol, 0.8-1.2% of Gemini surfactant, 0.1-0.5% of nano-cerium oxide, 1-3% of polyether-modified polysiloxane, 5-10% of carrier grafted with dimethylaminoethyl methacrylate, and 30-50% of water.

2. The cement raw meal grinding aid according to claim 1, characterized in that The deep eutectic solvent is a hydrophobic DES system composed of tetrabutylphosphine chloride and levulinic acid in a molar ratio of 1:3, and the contact angle is ≥110°.

3. The cement raw meal grinding aid according to claim 1, characterized in that The nano-cerium oxide is subjected to cryogenic plasma grafting treatment, and its surface is coated with an acrylic polymer shell layer, with a Zeta potential of ≤-45mV and a particle size distribution of 5±0.8nm.

4. The cement raw meal grinding aid according to claim 1, characterized in that The Gemini surfactant and perfluoropolyether are co-encapsulated in aerosol microcapsules synthesized by supercritical CO2. The microcapsule particle size is 1-3 μm and the rupture temperature is 80±5°C.

5. The method for preparing a cement raw meal grinding aid according to any one of claims 1 to 4, characterized in that: The method comprises the following preparation steps: Nano-cerium oxide pretreatment S1: In an argon environment at -50 ° C, nano-CeO2 was mixed with 5 wt% acrylic acid / methanol solution, subjected to 13.56 MHz radio frequency plasma treatment for 30 min, and then heated to -20 ° C under nitrogen protection and aged for 2 h; DES-crude glycerol co-solvent system construction S2: Tetrabutylphosphine chloride and levulinic acid were stirred and dissolved at 60°C in a molar ratio of 1:3, industrial crude glycerol purified by molecular distillation was added, and after degassing under a vacuum of 2 kPa, supercritical CO2 was injected to 15 MPa; In situ synthesis of microcapsules S3: Gemini surfactant and PFPE were mixed in a mass ratio of 2:1, turbulently stirred in a 25 MPa supercritical CO2 environment, and then rapidly depressurized through a coaxial atomizing nozzle to produce 1.2 ± 0.3 μm microcapsules; Multiphase system composite S4: pretreated nano-CeO2, DES-glycerol system, microcapsules and grafted DMAEMA carrier were added to a high-pressure homogenizer and circulated at 120°C and 50 MPa for 5 times; Aqueous system stabilization S5: Deionized water was added to the composite system in stages, and 40 kHz ultrasonic vibration was applied at intervals of 3 minutes between each stage, and the final pH was adjusted to 9.0-9.

5.

6. The method for preparing a cement raw meal grinding aid according to claim 5, wherein: In step S1 , the plasma treatment adopts a pulse mode with a duty cycle of 1:5, a pulse frequency of 10 kHz, and an acrylic acid monomer flux rate of 0.2 mL / min.

7. The method for preparing a cement raw meal grinding aid according to claim 5, wherein: The phase change rate of supercritical CO2 in step S3 is 50 MPa / s, the inner diameter of the coaxial atomizing nozzle is 0.15 mm, the outer diameter is 0.35 mm, and the gas-liquid ratio is 15:1.

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