Mineral powder grinding aid and preparation method thereof

Abstract

The invention discloses a mineral powder grinding aid and a preparation method thereof, and relates to the technical field of mineral powder grinding aids. The technical key points are composed of the following components in parts by weight: 40-60 parts of variable charge type modified bentonite nanosheets; 30-50 parts of phosphorus-containing organic polymer chelates; and 5-10 parts of modified aminosilanes. The technical effects are based on the directional induction of mineral phase structure and the variable charge regulation mechanism, and by precisely controlling the preparation of the variable charge type modified bentonite nanosheets and regulating the interlayer charge density, the selective dispersion of mineral powder is achieved, and the specific surface area of ​​the mineral powder is greatly increased. At the same time, the modified aminosilane and the phosphorus-containing organic polymer chelate act synergistically to directionally induce changes in the mineral phase structure, significantly stimulate the activity of the mineral powder, and effectively enhance the hydration reaction degree and mechanical properties of the mineral powder.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral powder grinding aids, in particular to a mineral powder grinding aid and a preparation method thereof. Background Art

[0002] Mineral powder grinding aids are additives that improve the grinding efficiency of mineral powder. Because mineral powder itself has poor grindability, is high in crystallinity, and has a high hardness, grinding aids are often added during grinding to improve the grinding effect. This reduces the possibility of fine particles agglomerating, wrapping, and adhering to the inner walls of the grinder, improves the dispersion of the various mineral powder components within the grinder, and improves the grinding effect and efficiency of the mineral powder.

[0003] Existing mineral powder grinding aids are mostly based on alcoholamines, sugars, or simple inorganic salts. While these improve grinding efficiency to a certain extent, they suffer from limited dispersion and insignificant activation of the mineral powder. Therefore, there is an urgent need to develop a new type of mineral powder grinding aid that can improve grinding efficiency while enhancing the selective recognition and directional effects of the mineral phase structure, thereby increasing the actual dispersion ability of the mineral powder and stimulating its activation. Summary of the Invention

[0004] In response to the deficiencies of the prior art, the present invention provides a mineral powder grinding aid, which achieves selective dispersion and activity stimulation of mineral powder through a mineral phase structure directional induction mechanism and a variable charge regulation mechanism, thereby significantly improving its grinding aid and activation performance.

[0005] To achieve the above object, the present invention provides the following technical solution: a mineral powder grinding aid, comprising the following components in parts by weight:

[0006] 40-60 parts of variable charge modified bentonite nanosheets;

[0007] 30-50 parts of phosphorus-containing organic polymer chelate;

[0008] 5-10 parts of modified aminosilane.

[0009] Preferably, the variable charge modified bentonite nanosheets are obtained by the following steps:

[0010] (a) Sodium bentonite was mixed with MgCl2·6H2O and LiCl at a cation exchange capacity of 100-120% and ultrasonically dispersed in an ethanol / water solution with a volume ratio of 3:1 for 30 min;

[0011] (b) Stepwise calcination: 200°C for 1 h to fix magnesium ions between layers, and 500°C for 2 h to activate lithium ion migration;

[0012] (c) The interlayer charge density is regulated between 0.5 and 1.2 eq / kg by adjusting the Li⁺ / Mg²⁺ molar ratio from 0.25 to 1.0.

[0013] Preferably, step (b) is carried out in a rotary tube furnace at a rotation speed of 20 rpm and a heating rate of 5° C. / min.

[0014] Preferably, the modified aminosilane is a Schiff base chelated silane, and its preparation steps are as follows:

[0015] γ-Aminopropyltriethoxysilane and 2-hydroxy-1-naphthaldehyde were mixed in a molar ratio of 1:1.5 and reacted at 50°C under nitrogen protection for 3 hours. The reaction formula is as follows:

[0016] .

[0017] Preferably, the phosphorus-containing organic polymer chelate is a block polyphosphonate, and the synthesis steps thereof specifically include:

[0018] Hydroxyethyl methacrylate and vinylphosphonic acid were RAFT polymerized at a molar ratio of 4:1 using 4-cyano-4-(thiobenzoyl)valeric acid as a chain transfer agent at 60°C for 6 h to obtain a polymer with a molecular weight of 15000±500 and a PDI ≤ 1.2.

[0019] A method for preparing a mineral powder grinding aid comprises the following steps:

[0020] Step 1: premixing the variable charge modified bentonite nanosheets and the phosphorus-containing polymer chelate at 38-42° C. in an inert atmosphere for 30 minutes;

[0021] Step 2: adding 20 wt% modified aminosilane ethanol solution dropwise at a rate of ≤5 ml / min;

[0022] Step 3: Use supercritical CO2 assisted spray drying at a pressure of 7.5-8.5 MPa and a temperature of 44-46°C to prepare a grinding aid powder.

[0023] Preferably, in step 2, the zeta potential of the system is monitored in real time. When the potential changes by ≥5 mV, the dropwise addition of the modified aminosilane ethanol solution is stopped, and the solution is stirred for 10 min until the potential stabilizes, and then the dropwise addition is continued.

[0024] Preferably, the atomized particle size of the supercritical spray drying in step 3 is controlled at 10-20 μm, and the CO2 flow rate is 50 L / min.

[0025] Compared with the prior art, the present invention provides a mineral powder grinding aid and a preparation method thereof, which have the following beneficial effects: based on the directional induction of the mineral phase structure and the variable charge regulation mechanism, by precisely controlling the preparation of variable charge modified bentonite nanosheets, the interlayer charge density is adjusted to achieve selective dispersion of the mineral powder, thereby greatly increasing the specific surface area of ​​the mineral powder. At the same time, the modified aminosilane and the phosphorus-containing organic polymer chelate act synergistically to directionally induce changes in the mineral phase structure, significantly stimulate the activity of the mineral powder, and effectively enhance the hydration reaction degree and mechanical properties of the mineral powder.

[0026] The synergistic effect of the above two mechanisms reduces the agglomeration of mineral powder particles, optimizes the grindability of mineral powder, significantly reduces the energy consumption of grinding, greatly saves energy consumption in the production process, reduces production costs and improves production efficiency.

[0027] The precise ratio of each component and the unique preparation process are key to the performance improvement. Step-by-step calcination and charge control of variable-charge modified bentonite nanosheets, Schiff base chelation of modified aminosilanes, RAFT polymerization of phosphorus-containing organic polymer chelates, and potential monitoring and supercritical CO2-assisted spray drying during the grinding aid preparation process ensure the stability and uniformity of the grinding aid product, providing reliable support for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a SEM image of the microscopic morphology of the product prepared in Example 1 of the present invention after being added to mineral powder and ball-milled for 20 minutes;

[0029] Figure 2 This is a SEM image of the microscopic morphology of the product prepared in Example 1 of the present invention after being added to mineral powder and ball-milled for 40 minutes;

[0030] Figure 3 This is a SEM image of the microscopic morphology of the product prepared in Example 1 of the present invention after being added to mineral powder and ball-milled for 60 minutes;

[0031] Figure 4 It is a test bar chart of specific surface area of ​​Examples and Comparative Examples in the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] Specific surface area test:

[0034] Test Procedure: Measured using the Blaine air permeometer method. First, dry the prepared mineral powder sample in an oven at 105-110°C to constant weight. After cooling to room temperature, accurately weigh a certain amount of sample and place it into a permeable cylinder until the sample layer reaches the specified height and compaction level. Connect the permeable cylinder to a pressure gauge, inject an appropriate amount of water into the pressure gauge, open the stopcock to allow the water to flow out, and after the water level stabilizes, close the stopcock. Record the time it takes for the water level to drop to a certain height. Repeat the measurement multiple times and calculate the average value.

[0035] Reference Standard: Based on the "Determination of Specific Surface Area of ​​Cement - Blaine Method" (GB / T8074-2008), this standard provides detailed regulations on instruments, equipment, operating procedures, data processing, etc. to ensure the accuracy and comparability of test results.

[0036] Grinding energy consumption test:

[0037] Test Procedure: A laboratory ball mill was used for a grinding test. A certain mass (e.g., 500 kg) of raw mineral powder was weighed, and various grinding aids (from the examples, comparative examples, and commercially available products) were added. The powder was then ground according to the specified grinding parameters (speed, grinding time, etc.). During the grinding process, the ball mill's power consumption was recorded. The power consumption per unit mass of mineral powder was calculated to determine the grinding energy consumption.

[0038] Reference standard: There is currently no national standard specifically for the energy consumption test of mineral powder grinding aids. You can refer to the industry practice of cement grinding-related energy consumption tests and conduct comparative tests under the same raw materials, grinding equipment, and grinding conditions to ensure the validity of the data.

[0039] C3S reaction rate test:

[0040] Testing Procedure: Chemical analysis methods are used. First, a mineral powder sample is mixed with an appropriate amount of water to form a slurry. The slurry is then cured under standard curing conditions for a specified period of time (e.g., 3 days, 7 days, 28 days). After curing, the slurry sample is crushed and ground into a fine powder. Unreacted C3S is then separated through chemical treatments such as selective dissolution. The unreacted C3S content is measured using X-ray fluorescence spectrometry (XRF) or other appropriate chemical analysis methods, and the C3S reaction rate is calculated.

[0041] Reference Standard: Refer to "Chemical Analysis Methods of Cement" (GB / T176-2017), which provides methods and processes for chemical analysis of cement and related materials, and is combined with the general method of C3S reaction rate testing in cement hydration-related research.

[0042] 28-day strength test:

[0043] Testing Procedure: According to the "Test Method for Cement Mortar Strength (ISO Method)" (GB / T17671-1999), mineral powder, cement, and standard sand are mixed in the specified ratio (e.g., the mineral powder to cement ratio is determined based on actual testing, cement:standard sand = 1:3). An appropriate amount of water is added to form a mortar specimen. The water-cement ratio of the mortar is determined according to test requirements. After forming the mortar specimen, it is cured in a moisture curing chamber for 24 hours, then demolded and placed in a standard curing room (temperature 20±1°C, relative humidity ≥95%) for up to 28 days. After the curing period, the specimen's flexural and compressive strengths are measured using a pressure testing machine.

[0044] Reference standard: GB / T17671-1999 has strict regulations on the preparation of mortar, maintenance of specimens, strength testing equipment and operating methods, etc. It is the authoritative standard for strength testing of cement and related cementitious materials.

[0045] RAFT polymerization, short for reversible addition-fragmentation chain transfer polymerization, is a living / controlled radical polymerization (CRP) technology based on a reversible chain transfer reaction. Its core principle is to introduce a RAFT agent (chain transfer agent) to achieve a rapid, reversible equilibrium between active species (free radicals) and dormant species (macromolecule chains) during the polymerization process, thereby effectively controlling the molecular weight, molecular weight distribution, and chain structure of the polymer.

[0046] Zeta potential measurement equipment, name: Zeta potential analyzer, model: NanoZS90 (Malvern, accuracy ±1mV), purpose: to test the surface charge density of mineral powder particles and verify the variable charge regulation mechanism.

[0047] Mineral structure analysis equipment, name: X-ray diffractometer (XRD), model: D8Advance (Bruker, Cu target, scanning range 5°~80°), purpose: to determine the crystal phase composition in mineral powder (such as changes in C3S and C2S content) and verify the directional induction effect of mineral structure.

[0048] Thermal analysis equipment, name: Differential Scanning Calorimeter (DSC), model: NETZSCHDSC204F1, purpose: to analyze the exothermic curve of the mineral powder hydration reaction and quantify the activity excitation efficiency (such as exothermic peak value and total heat release).

[0049] It should be noted that the instruments used in this application and other instruments that may be used only need to meet the corresponding usage requirements and are not specifically limited. Those skilled in the art may selectively use them according to specific circumstances.

[0050] Figure 1-Figure 3Acquired by field emission scanning electron microscope, model FEINovaNanoSEM450, sample preparation method: metal spraying (Pt or Au), fixed with conductive glue after drying, sample environment: vacuum chamber pressure of about 10⁻ 4 ~10⁻ 6 Pa, accelerating voltage: 5.0 kV, working distance (WD): 4.0 mm to 6.0 mm, detector: SE (secondary electron imaging), other information is detailed in Table 1;

[0051] Table 1

[0052]

[0053] Example 1: A mineral powder grinding aid is obtained by the following steps:

[0054] To prepare variable-charge modified bentonite nanosheets, sodium bentonite was mixed with MgCl₂・6H₂O and LiCl at 100% cation exchange capacity and ultrasonically dispersed in a 3:1 ethanol / water solution by volume for 30 minutes. The nanosheets were then calcined in a rotary tube furnace at 20 rpm and a heating rate of 5°C / min in a stepwise fashion, maintaining the temperature at 200°C for 1 hour and 500°C for 2 hours. The interlayer charge density was controlled to 0.5 eq / kg by using a Li⁺ / Mg²⁺ molar ratio of 0.25.

[0055] Preparation of modified aminosilane: γ-aminopropyltriethoxysilane and 2-hydroxy-1-naphthaldehyde were mixed in a molar ratio of 1:1.5 and reacted at 50°C under nitrogen for 3 hours to obtain Schiff base chelated silane.

[0056] Preparation of phosphorus-containing organic polymer chelate: Using 4-cyano-4-(thiobenzoyl)valeric acid as a chain transfer agent, hydroxyethyl methacrylate and vinylphosphonic acid were RAFT polymerized in a 4:1 molar ratio at 60°C for 6 h to obtain a block polyphosphonate with a molecular weight of 15,000 and a PDI of 1.2.

[0057] Preparation of a grinding aid for mineral powder: Premix 40 parts of the variable-charge modified bentonite nanosheets prepared above with 50 parts of a phosphorus-containing organic polymer chelate at 38°C under an inert atmosphere for 30 minutes. Add a 20 wt% modified aminosilane ethanol solution dropwise at a rate of 5 ml / min. Monitor the zeta potential of the system in real time. Pause addition when the potential changes by ≥5 mV. Stir for 10 minutes until the potential stabilizes, then continue. Prepare the grinding aid powder using supercritical CO₂-assisted spray drying at a pressure of 7.5 MPa, a temperature of 44°C, an atomized particle size of 10 μm, and a CO₂ flow rate of 50 L / min.

[0058] Example 2 is obtained by the following steps:

[0059] To prepare variable-charge modified bentonite nanosheets, sodium bentonite was mixed with MgCl₂・6H₂O and LiCl at a cation exchange capacity of 110%. The mixture was ultrasonically dispersed in a 3:1 ethanol / water solution by volume for 30 minutes. The nanosheets were then calcined in a rotary tube furnace at 20 rpm and a heating rate of 5°C / min in a stepwise fashion, maintaining the temperature at 200°C for 1 hour and 500°C for 2 hours. The interlayer charge density was controlled to 0.8 eq / kg by maintaining a Li⁺ / Mg²⁺ molar ratio of 0.5.

[0060] Preparation of modified aminosilane: same as Example 1.

[0061] Preparation of phosphorus-containing organic polymer chelate: Same as Example 1.

[0062] Preparation of a grinding aid for mineral powder: Premix 50 parts of variable-charge modified bentonite nanosheets and 40 parts of a phosphorus-containing organic polymer chelate at 40°C under an inert atmosphere for 30 minutes. Add a 20 wt% modified aminosilane ethanol solution dropwise at a rate of 4 ml / min. Monitor the zeta potential of the system in real time. Pause addition when the potential changes by ≥5 mV. Stir for 10 minutes until the potential stabilizes before continuing. Prepare the grinding aid powder using supercritical CO₂-assisted spray drying at a pressure of 8.0 MPa, a temperature of 45°C, an atomized particle size of 15 μm, and a CO₂ flow rate of 50 L / min.

[0063] Example 3 is obtained by the following steps:

[0064] To prepare variable-charge modified bentonite nanosheets, sodium bentonite was mixed with MgCl₂・6H₂O and LiCl at a cation exchange capacity of 120%. The mixture was ultrasonically dispersed in a 3:1 ethanol / water solution by volume for 30 minutes. The nanosheets were then calcined in a rotary tube furnace at 20 rpm and a heating rate of 5°C / min, with a stepwise heating period of 200°C for 1 hour and 500°C for 2 hours. The interlayer charge density was controlled to 1.2 eq / kg by maintaining a Li⁺ / Mg²⁺ molar ratio of 1.0.

[0065] Preparation of modified aminosilane: same as Example 1.

[0066] Preparation of phosphorus-containing organic polymer chelate: Same as Example 1.

[0067] Preparation of a grinding aid for mineral powder: 60 parts of variable-charge modified bentonite nanosheets and 30 parts of a phosphorus-containing organic polymer chelate were premixed at 42°C under an inert atmosphere for 30 minutes. A 20 wt% modified aminosilane ethanol solution was added dropwise at a rate of 3 ml / min. The zeta potential of the system was monitored in real time. Addition was paused when the potential changed by ≥5 mV. Stir for 10 minutes until the potential stabilized, then continue. The grinding aid powder was prepared using supercritical CO₂-assisted spray drying at a pressure of 8.5 MPa, a temperature of 46°C, an atomized particle size of 20 μm, and a CO₂ flow rate of 50 L / min.

[0068] Example 4 is obtained by the following steps:

[0069] Preparation of variable charge modified bentonite nanosheets: Same as Example 2.

[0070] Preparation of modified aminosilane: same as Example 1.

[0071] Preparation of phosphorus-containing organic polymer chelate: Same as Example 1.

[0072] Preparation of a grinding aid for mineral powder: Premix 45 parts of variable-charge modified bentonite nanosheets and 45 parts of a phosphorus-containing organic polymer chelate at 39°C under an inert atmosphere for 30 minutes. Add a 20 wt% modified aminosilane ethanol solution dropwise at a rate of 4.5 ml / min. Monitor the zeta potential of the system in real time. Pause addition when the potential changes by ≥5 mV. Stir for 10 minutes until the potential stabilizes before continuing. Prepare the grinding aid powder using supercritical CO₂-assisted spray drying at a pressure of 7.8 MPa, a temperature of 44.5°C, an atomized particle size of 12 μm, and a CO₂ flow rate of 50 L / min.

[0073] Example 5: Preparation of variable charge modified bentonite nanosheets: Same as Example 2.

[0074] Preparation of modified aminosilane: same as Example 1.

[0075] Preparation of phosphorus-containing organic polymer chelate: Same as Example 1.

[0076] Preparation of a grinding aid for mineral powder: Premix 55 parts of variable-charge modified bentonite nanosheets and 35 parts of a phosphorus-containing organic polymer chelate at 41°C under an inert atmosphere for 30 minutes. Add a 20 wt% modified aminosilane ethanol solution dropwise at a rate of 3.5 ml / min. Monitor the zeta potential of the system in real time. Pause addition when the potential changes by ≥5 mV. Stir for 10 minutes until the potential stabilizes before continuing. Prepare the grinding aid powder using supercritical CO₂-assisted spray drying at a pressure of 8.2 MPa, a temperature of 45.5°C, an atomized particle size of 18 μm, and a CO₂ flow rate of 50 L / min.

[0077] Comparative Example 1: Preparation of variable-charge modified bentonite nanosheets: Sodium bentonite was mixed with MgCl₂・6H₂O and LiCl at 80% of its cation exchange capacity. The mixture was ultrasonically dispersed in a 3:1 ethanol / water solution by volume for 30 minutes. The nanosheets were then calcined in a rotary tube furnace at 20 rpm and a heating rate of 5°C / min in a stepwise fashion, maintaining the temperature at 200°C for 1 hour and 500°C for 2 hours. The interlayer charge density was controlled to 0.3 eq / kg by maintaining a Li⁺ / Mg²⁺ molar ratio of 0.1.

[0078] Preparation of modified aminosilane: same as Example 1.

[0079] Preparation of phosphorus-containing organic polymer chelate: Same as Example 1.

[0080] Preparation of a grinding aid for mineral powder: 40 parts of the variable-charge modified bentonite nanosheets prepared above and 50 parts of a phosphorus-containing organic polymer chelate were premixed at 38°C under an inert atmosphere for 30 minutes. A 20 wt% solution of modified aminosilane in ethanol was added dropwise at a rate of 5 ml / min. Zeta potential was not monitored. Supercritical CO₂-assisted spray drying was used at a pressure of 7.5 MPa, a temperature of 44°C, and a CO₂ flow rate of 50 L / min to prepare a grinding aid powder.

[0081] Comparative Example 2: Preparation of variable charge modified bentonite nanosheets: same as Example 2.

[0082] Preparation of modified aminosilane: γ-aminopropyltriethoxysilane and 2-hydroxy-1-naphthaldehyde were mixed in a 1:1 molar ratio and reacted at 50°C under nitrogen for 3 hours to obtain silane.

[0083] Preparation of phosphorus-containing organic polymer chelate: Same as Example 1.

[0084] Preparation of a grinding aid for mineral powder: Premix 50 parts of variable-charge modified bentonite nanosheets and 40 parts of a phosphorus-containing organic polymer chelate at 40°C under an inert atmosphere for 30 minutes. Add a 20 wt% modified aminosilane ethanol solution dropwise at a rate of 4 ml / min. Monitor the zeta potential of the system in real time. Pause addition when the potential changes by ≥5 mV. Stir for 10 minutes until the potential stabilizes before continuing. Prepare the grinding aid powder using supercritical CO₂-assisted spray drying at a pressure of 8.0 MPa, a temperature of 45°C, an atomized particle size of 15 μm, and a CO₂ flow rate of 50 L / min.

[0085] Comparative Example 3: Preparation of variable charge modified bentonite nanosheets: Same as Example 3.

[0086] Preparation of modified aminosilane: same as Example 1.

[0087] Preparation of phosphorus-containing organic polymer chelate: Using 4-cyano-4-(thiobenzoyl)valeric acid as a chain transfer agent, RAFT polymerization of hydroxyethyl methacrylate and vinylphosphonic acid in a molar ratio of 3:1 was carried out at 60°C for 6 hours to obtain a polymer with a molecular weight of 12,000 and a PDI of 1.5.

[0088] Preparation of mineral powder grinding aid: Take 60 parts of variable charge type modified bentonite nanosheets and 30 parts of phosphorus-containing organic polymer chelate, and premix them for 30 minutes under an inert atmosphere at 42°C. Add 20wt% modified aminosilane ethanol solution at a rate of 3ml / min, monitor the Zeta potential of the system in real time, and stop adding when the potential changes by ≥5mV. Stir for 10 minutes until the potential stabilizes and then continue. Use supercritical CO2 assisted spray drying, pressure 8.5MPa, temperature 46°C, atomized particle size controlled at 20μm, CO2 flow rate of 50L / min to prepare grinding aid powder.

[0089] Comparative Example 4: Preparation of variable charge modified bentonite nanosheets: same as Example 2.

[0090] Preparation of modified aminosilane: same as Example 1.

[0091] Preparation of phosphorus-containing organic polymer chelate: Same as Example 1.

[0092] Preparation of a grinding aid for mineral powder: Premix 45 parts of variable-charge modified bentonite nanosheets and 45 parts of a phosphorus-containing organic polymer chelate at 39°C under an inert atmosphere for 30 minutes. Add a 20 wt% modified aminosilane ethanol solution dropwise at a rate of 4.5 ml / min. Monitor the zeta potential of the system in real time, and continue adding the solution until the potential changes by 5 mV or more. Prepare the grinding aid powder using supercritical CO₂-assisted spray drying at a pressure of 7.8 MPa, a temperature of 44.5°C, and a CO₂ flow rate of 50 L / min. Atomized particle size of 12 μm was maintained.

[0093] Comparative Example 5: Preparation of variable charge modified bentonite nanosheets: same as Example 2.

[0094] Preparation of modified aminosilane: same as Example 1.

[0095] Preparation of phosphorus-containing organic polymer chelate: Same as Example 1.

[0096] Preparation of a grinding aid for mineral powder: 55 parts of variable-charge modified bentonite nanosheets and 35 parts of a phosphorus-containing organic polymer chelate were premixed at 41°C under an inert atmosphere for 30 minutes. A 20 wt% modified aminosilane ethanol solution was added dropwise at a rate of 3.5 ml / min. The zeta potential of the system was monitored in real time. Addition was paused when the potential changed by ≥5 mV. Stir for 10 minutes until the potential stabilized, then continue. The grinding aid powder was prepared using conventional spray drying (not supercritical CO2-assisted) at 45.5°C with an atomized particle size of 18 μm.

[0097] Comparative Example 6: Purchase commercially available triethanolamine grinding aid, the manufacturer is Jinan Juxing Chemical Co., Ltd., the main component contains polymerized polyols, the effective ingredient accounts for 85%-90%, and also contains glycerol, glycerol esters, polyglycerol esters, other ternary organic substances, and water.

[0098] The mineral powder grinding aids obtained in Examples 1, 2, 3, 4, 5 and Comparative Examples 1, 2, 3, 4, 5 and 6 were grouped and numbered, respectively, as ZMJ25-01, ZMJ25-02, ZMJ25-03, ZMJ25-04, ZMJ25-05, ZMJ25-06, ZMJ25-07, ZMJ25-08, ZMJ25-09, ZMJ25-010 and ZMJ25-011. The physical properties of the products of the Examples and Comparative Examples were tested, including specific surface area (m² / kg), grinding energy consumption (kWh / t), C3S reaction rate (%) and 28-day strength (MPa). The specific test results are shown in Tables 2 and 3.

[0099] Table 2 shows the test results of specific surface area and grinding energy consumption

[0100]

[0101] Table 3 shows the test results of C3S reaction rate and 28-day strength

[0102]

[0103] Variable charge regulation mechanism improves selective dispersion effect: In the embodiment, by precisely controlling the preparation of variable charge modified bentonite nanosheets and adjusting the Li⁺ / Mg²⁺ molar ratio, the interlayer charge density is controlled at 0.5-1.2eq / kg. This enables the grinding aid to achieve selective dispersion based on the surface charge characteristics of the mineral powder particles. Compared with commercially available grinding aids and comparative examples, the mineral powder specific surface area of ​​the embodiment is significantly higher, up to 500m² / kg, while the commercially available grinding aid is only 410m² / kg. A higher specific surface area means that the mineral powder particles are more evenly dispersed, indicating that the variable charge regulation mechanism significantly enhances the dispersibility of the grinding aid.

[0104] The directional induction mechanism of mineral phase structure stimulates the activity of mineral powder: The modified aminosilane and phosphorus-containing organic polymer chelate of the present invention work synergistically to achieve directional induction of mineral phase structure. The Schiff base chelated silane formed by the modified aminosilane and the specifically synthesized block polyphosphonate can react with the active ingredients in the mineral powder to induce changes in the mineral phase structure. From the test data, the C3S reaction rate of the embodiment reached as high as 88%, and the maximum 28-day strength was 60MPa, far exceeding the 73% and 51.5MPa of the commercial grinding aids, as well as the performance indicators of the comparative examples, fully demonstrated that this mechanism effectively stimulated the activity of the mineral powder and improved the degree of hydration reaction and strength of the mineral powder.

[0105] Synergistic Effect Reduces Grinding Energy Consumption: The synergistic effect of the variable charge regulation mechanism and the oriented mineral structure induction mechanism not only improves dispersion and activation performance, but also significantly reduces grinding energy consumption. The grinding energy consumption of the embodiment is as low as 25 kWh / t, lower than the 30.5 kWh / t of commercially available grinding aids. This is because the excellent dispersibility reduces particle agglomeration, facilitating grinding, while the optimized mineral structure makes the mineral powder easier to grind, thereby reducing overall grinding energy consumption.

[0106] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications based on the present invention to solve substantially the same technical problems and achieve substantially the same technical effects are all included in the scope of protection of the present invention.

Claims

1. A mineral powder grinding aid, characterized in that: It is composed of the following components in parts by weight: 40-60 parts of variable charge modified bentonite nanosheets; The variable charge type modified bentonite nanosheets are obtained by the following steps: (a) Sodium bentonite was mixed with MgCl2·6H2O and LiCl at a cation exchange capacity of 100-120% and ultrasonically dispersed in an ethanol / water solution with a volume ratio of 3:1 for 30 min; (b) Stepwise calcination: 200°C for 1 h to fix magnesium ions between layers, and 500°C for 2 h to activate lithium ion migration; (c) The interlayer charge density is regulated between 0.5 and 1.2 eq / kg by adjusting the Li⁺ / Mg²⁺ molar ratio from 0.25 to 1.0; 30-50 parts of phosphorus-containing organic polymer chelate; The phosphorus-containing organic polymer chelate is a block polyphosphonate, and its synthesis steps specifically include: Hydroxyethyl methacrylate and vinylphosphonic acid were RAFT-polymerized at a molar ratio of 4:1 using 4-cyano-4-(thiobenzoyl)valeric acid as a chain transfer agent at 60°C for 6 h to obtain a polymer with a molecular weight of 15,000 ± 500 and a PDI of ≤ 1.

2. 5-10 parts of modified aminosilane; The modified aminosilane is a Schiff base chelated silane, and its preparation steps are as follows: γ-Aminopropyltriethoxysilane and 2-hydroxy-1-naphthaldehyde were mixed in a molar ratio of 1:1.5 and reacted at 50°C under nitrogen protection for 3 hours. The reaction formula is as follows: 。 2. A mineral powder grinding aid according to claim 1, characterized in that: Step (b) is carried out in a rotary tube furnace at a rotation speed of 20 rpm and a heating rate of 5° C. / min.

3. A method for preparing the mineral powder grinding aid according to any one of claims 1 to 2, characterized in that: The following steps are involved: Step 1: premixing the variable charge modified bentonite nanosheets and the phosphorus-containing polymer chelate at 38-42° C. in an inert atmosphere for 30 minutes; Step 2: adding 20 wt% modified aminosilane ethanol solution dropwise at a rate of ≤5 ml / min; Step 3: Use supercritical CO2 assisted spray drying at a pressure of 7.5-8.5 MPa and a temperature of 44-46°C to prepare a grinding aid powder.

4. The method for preparing the mineral powder grinding aid according to claim 3, wherein: In step 2, the zeta potential of the system was monitored in real time. When the potential changed by ≥5 mV, the addition of the modified aminosilane ethanol solution was stopped and stirred for 10 min until the potential stabilized before continuing.

5. The method for preparing the mineral powder grinding aid according to claim 3, wherein: In step 3, the atomized particle size of the supercritical spray drying is controlled at 10-20 μm, and the CO2 flow rate is 50 L / min.

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