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, and the mineral powder grinding aid is technically characterized by comprising the following components by weight: 40-60 parts of variable charge type modified bentonite nanosheets; 30 to 50 parts of a phosphorus-containing organic polymer chelate; 5 to 10 parts of modified amino silane; the technical effect is based on directional induction of a mineral phase structure and a variable charge regulation mechanism, selective dispersion of mineral powder is realized by accurately controlling preparation of variable charge type modified bentonite nanosheets and regulating interlayer charge density, so that the specific surface area of the mineral powder is greatly increased, and meanwhile, the modified amino silane and the phosphorus-containing organic polymer chelate have a synergistic effect, so that the specific surface area of the mineral powder is greatly increased. The mineral phase structure change is directionally induced, the mineral powder activity is obviously excited, and the hydration reaction degree and the mechanical property of the mineral powder are effectively enhanced.

Description

Technical Field

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

[0002] An ore powder grinding aid is an additive to improve the grinding efficiency of ore powder. Since the ore powder itself has poor grindability, many crystals, and high hardness, in order to improve the grinding effect of the ore powder, a grinding aid is usually added during the grinding of the ore powder to reduce the possibility of fine particles of the ore powder agglomerating, wrapping, and adhering to the inner wall of the grinding machine, improve the dispersibility among the components of the ore powder in the grinding machine, and improve the grinding effect and grinding efficiency of the ore powder.

[0003] Existing ore powder grinding aids are mostly based on alkanolamines, sugars, or simple inorganic salts. Although they improve the grinding efficiency of the ore powder to a certain extent, there are problems such as limited dispersing ability and insignificant ore powder activity excitation effect. Therefore, there is an urgent need to develop a new type of ore powder grinding aid that can enhance the selective recognition and directional action on the ore phase structure while improving the grinding efficiency, and improve the actual dispersing ability of the ore powder and the ore powder activity excitation effect. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides an ore powder grinding aid, which realizes the selective dispersion and activity excitation of the ore powder through the ore phase structure directional induction mechanism and the variable charge regulation mechanism, and significantly improves its grinding and activation performance.

[0005] To achieve the above object, the present invention provides the following technical solution: An ore powder grinding aid is 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; 5 - 10 parts of modified aminosilane.

[0006] Preferably, the variable charge type modified bentonite nanosheets are obtained through the following steps: (a) Mix sodium bentonite with MgCl₂·6H₂O and LiCl according to 100 - 120% of the cation exchange capacity, and ultrasonically disperse in a solution with an ethanol / water volume ratio of 3:1 for 30 min; (b) Stepwise temperature-rising calcination: Keep at 200°C for 1 h to fix magnesium ions between the layers, and keep at 500°C for 2 h to activate the migration of lithium ions; (c) The interlayer charge density is regulated between 0.5 - 1.2 eq / kg through the Li⁺ / Mg²⁺ molar ratio of 0.25 - 1.0.

[0007] 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.

[0008] Preferably, the modified amino silane is a Schiff base chelated silane, and its preparation steps are as follows: Mix γ-aminopropyltriethoxysilane and 2-hydroxy-1-naphthaldehyde in a molar ratio of 1:1.5, and react at 50 °C under nitrogen protection for 3 h. The reaction formula is as follows: .

[0009] Preferably, the phosphorus-containing organic polymer chelate is a block polyphosphonate, and its synthesis steps specifically include: Using 4-cyano-4-(thiobenzoyl) pentanoic acid as a chain transfer agent, conduct RAFT polymerization of 2-hydroxyethyl methacrylate and vinyl phosphonic acid in a molar ratio of 4:1, and react at 60 °C for 6 h to obtain a polymer with a molecular weight of 15000 ± 500 and a PDI ≤ 1.2.

[0010] A preparation method of a mineral powder grinding aid includes the following steps: Step 1: Premix the variable charge type modified bentonite nanosheets and the phosphorus-containing polymer chelate in an inert atmosphere at 38 - 42 °C for 30 min; Step 2: Dropwise add a 20 wt% modified amino silane ethanol solution at a rate of ≤ 5 ml / min; Step 3: Use supercritical CO2-assisted spray drying, with a pressure of 7.5 - 8.5 MPa and a temperature of 44 - 46 °C, to prepare the grinding aid powder.

[0011] Preferably, in Step 2, the Zeta potential of the system is monitored in real time. When the potential change ≥ 5 mV, stop dropping the modified amino silane ethanol solution, stir for 10 min until the potential is stable, and then continue dropping.

[0012] Preferably, in Step 3, the atomization particle size of the supercritical spray drying is controlled at 10 - 20 μm, and the CO2 flow rate is 50 L / min.

[0013] Compared with the prior art, the present invention provides a mineral powder grinding aid and its preparation method, having the following beneficial effects: Based on the mechanism of directional induction of the mineral phase structure and variable charge regulation, by precisely controlling the preparation of the variable charge type modified bentonite nanosheets, adjusting the interlayer charge density, realizing the selective dispersion of the mineral powder, greatly increasing the specific surface area of the mineral powder. At the same time, the modified amino silane 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, effectively enhance the degree of hydration reaction and mechanical properties of the mineral powder.

[0014] The synergistic effect of the above two mechanisms reduces the agglomeration of mineral powder particles, optimizes the grindability of the mineral powder, significantly reduces the grinding energy consumption, greatly saves the energy consumption in the production process, reduces the production cost, and improves the production efficiency.

[0015] The precise proportion of each component and the unique preparation process are the keys to performance improvement. The stepwise heating calcination and charge regulation of variable charge modified bentonite nanosheets, the Schiff base chelation reaction of modified aminosilane, the RAFT polymerization of phosphorus-containing organic polymer chelates, as well as the potential monitoring and supercritical CO2-assisted spray drying during the preparation of the grinding aid ensure the stability and uniformity of the grinding aid product quality, providing a reliable guarantee for large-scale industrial production. Description of the Drawings

[0016] Figure 1 SEM image of the microscopic morphology after the product prepared in Example 1 of the present invention was added to the ore powder and milled for 20 min; Figure 2 SEM image of the microscopic morphology after the product prepared in Example 1 of the present invention was added to the ore powder and milled for 40 min; Figure 3 SEM image of the microscopic morphology after the product prepared in Example 1 of the present invention was added to the ore powder and milled for 60 min; Figure 4 Bar chart of the specific surface area test for the examples and comparative examples in the present invention. Detailed Description of the Invention

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0018] Specific surface area test: Test steps: The Blaine permeameter method was used for determination. First, the prepared ore powder sample was dried in an oven at 105 - 110 °C until constant weight. After cooling to room temperature, a certain amount of the sample was accurately weighed and loaded into the permeameter cylinder to make the sample layer reach the specified height and compaction degree. The permeameter cylinder was connected to the manometer, an appropriate amount of water was injected into the manometer, the piston was opened to let the water in the manometer flow out, and after the water level in the manometer was stable, the piston was closed and the time required for the water level to drop a certain height was recorded. The measurement was repeated multiple times and the average value was taken.

[0019] Reference standard: According to the "Determination Method for Specific Surface Area of Cement - Blaine Method" (GB / T8074 - 2008), this standard has detailed regulations on instrument equipment, operation steps, data processing, etc., ensuring the accuracy and comparability of test results.

[0020] Grinding energy consumption test: Test steps: Conduct grinding tests using a laboratory ball mill. Weigh a certain mass of raw ore powder (such as 500 kg), add different grinding aids (examples, comparative examples, and market products), and perform grinding according to the set grinding parameters (rotation speed, grinding time, etc.). During the grinding process, record the power consumption of the ball mill, and obtain the grinding energy consumption by calculating the power consumption per unit mass of ore powder.

[0021] Reference standard: Currently, there is no national standard specifically for testing the grinding energy consumption of ore powder grinding aids. The industry customary practices for relevant energy consumption tests of cement grinding can be referred to. Comparative tests are carried out under the same raw materials, grinding equipment, and grinding conditions to ensure the validity of the data.

[0022] C3S reaction rate test: Test steps: Adopt chemical analysis methods. First, mix the ore powder sample with an appropriate amount of water to make a neat paste, and cure it for a certain period of time (3 days, 7 days, 28 days, etc.) under standard curing conditions. After curing, break and grind the neat paste sample into fine powder, and separate the unreacted C3S through chemical treatment methods such as selective dissolution. Use an X-ray fluorescence spectrometer (XRF) or other suitable chemical analysis methods to measure the content of unreacted C3S, and calculate the C3S reaction rate.

[0023] Reference standard: Refer to "Methods of Chemical Analysis of Cement" (GB / T 176-2017). This standard provides methods and procedures for chemical analysis of cement and related materials, and is carried out in combination with the general methods for testing the C3S reaction rate in relevant research on cement hydration.

[0024] 28-day strength test: Test steps: According to "Methods of Testing Cement Mortar Strength (ISO Method)" (GB / T 17671-1999), mix the ore powder with cement and standard sand in a specified ratio (such as the ratio of ore powder to cement is set according to the actual test, cement: standard sand = 1:3), add an appropriate amount of water to make mortar specimens, and the water-cement ratio of the mortar is determined according to the test requirements. After the mortar specimens are formed, cure them in a humidity curing box for 24 h and then demold, and then place them in a standard curing room (temperature 20 ± 1 °C, relative humidity ≥ 95%) for curing until 28 days. After the curing period expires, use a compression testing machine to measure the flexural strength and compressive strength of the specimens.

[0025] Reference standard: The GB / T 17671-1999 standard has strict regulations on the preparation of mortar, specimen curing, strength testing equipment, and operation methods, etc. It is an authoritative standard for strength testing of cement and related cementitious materials.

[0026] RAFT polymerization, whose full name is Reversible Addition-Fragmentation Chain Transfer polymerization, is a living / controlled radical polymerization (CRP) technology based on reversible chain transfer reactions. Its core principle is to introduce RAFT reagents (chain transfer agents) to achieve a rapid reversible equilibrium between active species (free radicals) and dormant species (macromolecular chains) during the polymerization process, thereby effectively controlling the molecular weight, molecular weight distribution, and chain structure of the polymer.

[0027] Zeta potential measurement device, name: Zeta potential analyzer, model: NanoZS90 (Malvern, accuracy ±1 mV), use: to test the surface charge density of mineral powder particles and verify the variable charge regulation mechanism.

[0028] Mineral phase structure analysis device, name: X-ray diffractometer (XRD), model: D8 Advance (Bruker, Cu target, scanning range 5° - 80°), use: to determine the crystal phase composition in mineral powder (such as changes in the content of C3S and C2S) and verify the effect of mineral phase structure orientation induction.

[0029] Thermal analysis device, name: Differential Scanning Calorimeter (DSC), model: NETZSCH DSC204F1, use: to analyze the exothermic curve of the hydration reaction of mineral powder and quantify the activation efficiency (such as exothermic peak value, total heat release).

[0030] It should be noted that for the instruments used in this application and other instruments that need to be used, only meeting the corresponding usage requirements is sufficient, and there is no specific limitation. Those skilled in the art can make selective use according to the specific situation.

[0031] Figures 1-3 Obtained by a field emission scanning electron microscope, model: FEI Nova NanoSEM450, sample preparation method: metal spraying (Pt or Au), fixed with conductive glue after drying, sample environment: pressure in the vacuum chamber is about 10⁻ 4 ~10⁻ 6 Pa, acceleration voltage: 5.0 kV, working distance (WD): 4.0 mm - 6.0 mm, detector: SE (secondary electron imaging), other information is shown in Table 1; Table 1

[0032] Example 1: A mineral powder grinding aid is obtained through the following steps: Preparation of variable charge modified bentonite nanosheets: Take sodium bentonite, mix it with MgCl₂·6H₂O and LiCl according to 100% of the cation exchange capacity, and ultrasonically disperse it in a solution with an ethanol / water volume ratio of 3:1 for 30 min. In a rotary tube furnace, carry out stepwise temperature rising calcination at a rotation speed of 20 rpm and a heating rate of 5 °C / min, keep the temperature at 200 °C for 1 h and at 500 °C for 2 h, and regulate the interlayer charge density to 0.5 eq / kg through a Li⁺ / Mg²⁺ molar ratio of 0.25.

[0033] Preparation of modified amino silane: Mix γ-aminopropyltriethoxysilane and 2-hydroxy-1-naphthaldehyde according to a molar ratio of 1:1.5, and react under nitrogen protection at 50 °C for 3 h to obtain Schiff base chelated silane.

[0034] Preparation of phosphorus-containing organic polymer chelate: Using 4-cyano-4-(thiobenzoyl) pentanoic acid as a chain transfer agent, carry out RAFT polymerization of 2-hydroxyethyl methacrylate and vinyl phosphonic acid according to a molar ratio of 4:1, react at 60 °C for 6 h, and obtain a block polyphosphonate with a molecular weight of 15000 and a PDI of 1.2.

[0035] Preparation of mineral powder grinding aid: Take 40 parts of the variable charge modified bentonite nanosheets prepared above and 50 parts of the phosphorus-containing organic polymer chelate, and premix them in an inert atmosphere at 38 °C for 30 min. Dropwise add a 20 wt% ethanol solution of modified amino silane at a rate of 5 ml / min, and monitor the Zeta potential of the system in real time. When the potential change ≥ 5 mV, stop dropping, stir for 10 min until the potential is stable, and then continue. Use supercritical CO₂-assisted spray drying, with a pressure of 7.5 MPa, a temperature of 44 °C, control the atomization particle size at 10 μm, and a CO₂ flow rate of 50 L / min to prepare the grinding aid powder.

[0036] Example 2 is obtained through the following steps: Preparation of variable charge modified bentonite nanosheets: Take sodium bentonite, mix it with MgCl₂·6H₂O and LiCl according to 110% of the cation exchange capacity, and ultrasonically disperse it in a solution with an ethanol / water volume ratio of 3:1 for 30 min. In a rotary tube furnace, carry out stepwise temperature rising calcination at a rotation speed of 20 rpm and a heating rate of 5 °C / min, keep the temperature at 200 °C for 1 h and at 500 °C for 2 h, and regulate the interlayer charge density to 0.8 eq / kg through a Li⁺ / Mg²⁺ molar ratio of 0.5.

[0037] Preparation of modified amino silane: The same as Example 1.

[0038] Preparation of phosphorus-containing organic polymer chelate: The same as Example 1.

[0039] Preparation of grinding aid for ore powder: Take 50 parts of variable charge type modified bentonite nanosheets and 40 parts of phosphorus-containing organic polymer chelates, and premix them in an inert atmosphere at 40 °C for 30 min. Dropwise add 20 wt% modified amino silane ethanol solution at a rate of 4 ml / min, and monitor the Zeta potential of the system in real time. When the potential change ≥ 5 mV, stop dropping, stir for 10 min until the potential is stable, and then continue. Use supercritical CO2-assisted spray drying, with a pressure of 8.0 MPa, a temperature of 45 °C, the atomization particle size controlled at 15 μm, and the CO2 flow rate of 50 L / min to prepare the grinding aid powder.

[0040] Example 3 is obtained through the following steps: Preparation of variable charge type modified bentonite nanosheets: Take sodium bentonite, mix it with MgCl2·6H2O and LiCl according to 120% of the cation exchange capacity, and ultrasonically disperse it in a solution with an ethanol / water volume ratio of 3:1 for 30 min. In a rotary tube furnace, perform stepwise temperature rise calcination at a rotation speed of 20 rpm and a heating rate of 5 °C / min, keep it at 200 °C for 1 h, and keep it at 500 °C for 2 h, and regulate the interlayer charge density to 1.2 eq / kg by the Li⁺ / Mg²⁺ molar ratio of 1.0.

[0041] Preparation of modified amino silane: The same as Example 1.

[0042] Preparation of phosphorus-containing organic polymer chelates: The same as Example 1.

[0043] Preparation of grinding aid for ore powder: Take 60 parts of variable charge type modified bentonite nanosheets and 30 parts of phosphorus-containing organic polymer chelates, and premix them in an inert atmosphere at 42 °C for 30 min. Dropwise add 20 wt% modified amino silane ethanol solution at a rate of 3 ml / min, and monitor the Zeta potential of the system in real time. When the potential change ≥ 5 mV, stop dropping, stir for 10 min until the potential is stable, and then continue. Use supercritical CO2-assisted spray drying, with a pressure of 8.5 MPa, a temperature of 46 °C, the atomization particle size controlled at 20 μm, and the CO2 flow rate of 50 L / min to prepare the grinding aid powder.

[0044] Example 4 is obtained through the following steps: Preparation of variable charge type modified bentonite nanosheets: The same as Example 2.

[0045] Preparation of modified amino silane: The same as Example 1.

[0046] Preparation of phosphorus-containing organic polymer chelates: The same as Example 1.

[0047] Preparation of grinding aid for mineral powder: Take 45 parts of variable charge type modified bentonite nanosheets and 45 parts of phosphorus-containing organic polymer chelate, and premix them in an inert atmosphere at 39 °C for 30 min. Dropwise add 20 wt% modified amino silane ethanol solution at a rate of 4.5 ml / min, and monitor the Zeta potential of the system in real time. When the potential change ≥ 5 mV, stop dropwise addition, stir for 10 min until the potential is stable, and then continue. Use supercritical CO2-assisted spray drying, with a pressure of 7.8 MPa, a temperature of 44.5 °C, the atomization particle size controlled at 12 μm, and the CO2 flow rate of 50 L / min to prepare the grinding aid powder.

[0048] Example 5. Preparation of variable charge type modified bentonite nanosheets: The same as Example 2.

[0049] Preparation of modified amino silane: The same as Example 1.

[0050] Preparation of phosphorus-containing organic polymer chelate: The same as Example 1.

[0051] Preparation of grinding aid for mineral powder: Take 55 parts of variable charge type modified bentonite nanosheets and 35 parts of phosphorus-containing organic polymer chelate, and premix them in an inert atmosphere at 41 °C for 30 min. Dropwise add 20 wt% modified amino silane ethanol solution at a rate of 3.5 ml / min, and monitor the Zeta potential of the system in real time. When the potential change ≥ 5 mV, stop dropwise addition, stir for 10 min until the potential is stable, and then continue. Use supercritical CO2-assisted spray drying, with a pressure of 8.2 MPa, a temperature of 45.5 °C, the atomization particle size controlled at 18 μm, and the CO2 flow rate of 50 L / min to prepare the grinding aid powder.

[0052] Comparative Example 1. Preparation of variable charge type modified bentonite nanosheets: Take sodium bentonite, mix it with MgCl2・6H2O and LiCl according to 80% of the cation exchange capacity, and ultrasonically disperse it in a solution with an ethanol / water volume ratio of 3:1 for 30 min. In a rotary tube furnace, carry out stepwise temperature rise calcination at a rotation speed of 20 rpm and a heating rate of 5 °C / min, keep it at 200 °C for 1 h and at 500 °C for 2 h, and regulate the interlayer charge density to 0.3 eq / kg by the Li⁺ / Mg²⁺ molar ratio of 0.1.

[0053] Preparation of modified amino silane: The same as Example 1.

[0054] Preparation of phosphorus-containing organic polymer chelate: The same as Example 1.

[0055] Preparation of grinding aid for ore powder: Take 40 parts of the variable-charge modified bentonite nanosheets prepared above and 50 parts of phosphorus-containing organic polymer chelate, and premix them for 30 min under an inert atmosphere at 38 °C. Dropwise add a 20 wt% modified amino silane ethanol solution at a rate of 5 ml / min without monitoring the Zeta potential. Use supercritical CO2-assisted spray drying at a pressure of 7.5 MPa, a temperature of 44 °C, control the atomization particle size at 10 μm, and a CO2 flow rate of 50 L / min to prepare the grinding aid powder.

[0056] Comparative Example 2: Preparation of variable-charge modified bentonite nanosheets: The same as in Example 2.

[0057] Preparation of modified amino silane: Mix γ-aminopropyltriethoxysilane and 2-hydroxy-1-naphthaldehyde in a molar ratio of 1:1, and react for 3 h under nitrogen protection at 50 °C to obtain the silane.

[0058] Preparation of phosphorus-containing organic polymer chelate: The same as in Example 1.

[0059] Preparation of grinding aid for ore powder: Take 50 parts of variable-charge modified bentonite nanosheets and 40 parts of phosphorus-containing organic polymer chelate, and premix them for 30 min under an inert atmosphere at 40 °C. Dropwise add a 20 wt% modified amino silane ethanol solution at a rate of 4 ml / min, and monitor the Zeta potential of the system in real time. When the potential change ≥ 5 mV, stop dropwise addition, stir for 10 min until the potential is stable, and then continue. Use supercritical CO2-assisted spray drying at a pressure of 8.0 MPa, a temperature of 45 °C, control the atomization particle size at 15 μm, and a CO2 flow rate of 50 L / min to prepare the grinding aid powder.

[0060] Comparative Example 3: Preparation of variable-charge modified bentonite nanosheets: The same as in Example 3.

[0061] Preparation of modified amino silane: The same as in Example 1.

[0062] Preparation of phosphorus-containing organic polymer chelate: Using 4-cyano-4-(thiobenzoyl) pentanoic acid as a chain transfer agent, carry out RAFT polymerization of 2-hydroxyethyl methacrylate and vinylphosphonic acid in a molar ratio of 3:1, and react at 60 °C for 6 h to obtain a polymer with a molecular weight of 12000 and a PDI of 1.5.

[0063] Preparation of grinding aid for mineral powder: Take 60 parts of variable-charge modified bentonite nanosheets and 30 parts of phosphorus-containing organic polymer chelates, and premix them in an inert atmosphere at 42 °C for 30 min. Dropwise add a 20 wt% modified amino silane ethanol solution at a rate of 3 ml / min, and monitor the Zeta potential of the system in real time. When the potential change ≥ 5 mV, stop dropping, stir for 10 min until the potential is stable, and then continue. Use supercritical CO2-assisted spray drying, with a pressure of 8.5 MPa, a temperature of 46 °C, the atomization particle size controlled at 20 μm, and the CO2 flow rate of 50 L / min to prepare the grinding aid powder. Comparative Example 4, Preparation of variable-charge modified bentonite nanosheets: The same as in Example 2.

[0064] Preparation of modified amino silane: The same as in Example 1.

[0065] Preparation of phosphorus-containing organic polymer chelates: The same as in Example 1.

[0066] Preparation of grinding aid for mineral powder: Take 45 parts of variable-charge modified bentonite nanosheets and 45 parts of phosphorus-containing organic polymer chelates, and premix them in an inert atmosphere at 39 °C for 30 min. Dropwise add a 20 wt% modified amino silane ethanol solution at a rate of 4.5 ml / min, and monitor the Zeta potential of the system in real time. When the potential change ≥ 5 mV, do not stop dropping. Use supercritical CO2-assisted spray drying, with a pressure of 7.8 MPa, a temperature of 44.5 °C, the atomization particle size controlled at 12 μm, and the CO2 flow rate of 50 L / min to prepare the grinding aid powder.

[0067] Comparative Example 5, Preparation of variable-charge modified bentonite nanosheets: The same as in Example 2.

[0068] Preparation of modified amino silane: The same as in Example 1.

[0069] Preparation of phosphorus-containing organic polymer chelates: The same as in Example 1.

[0070] Preparation of grinding aid for mineral powder: Take 55 parts of variable-charge modified bentonite nanosheets and 35 parts of phosphorus-containing organic polymer chelates, and premix them in an inert atmosphere at 41 °C for 30 min. Dropwise add a 20 wt% modified amino silane ethanol solution at a rate of 3.5 ml / min, and monitor the Zeta potential of the system in real time. When the potential change ≥ 5 mV, stop dropping, stir for 10 min until the potential is stable, and then continue. Use ordinary spray drying (not supercritical CO2-assisted), with a temperature of 45.5 °C, the atomization particle size controlled at 18 μm to prepare the grinding aid powder.

[0071] Comparative Example 6, Purchase a commercially available triethanolamine grinding aid from Jinan Juxing Chemical Co., Ltd. The main components include polyhydric alcohols, the effective component accounts for 85% - 90%, and it also contains glycerol, glycerol esters, polyglycerol esters, other ternary organic substances, and water.

[0072] The mineral powder grinding aids obtained from Examples 1, 2, 3, 4, 5 and Comparative Examples 1, 2, 3, 4, 5, 6 were grouped and numbered in sequence as ZMJ25-01, ZMJ25-02, ZMJ25-03, ZMJ25-04, ZMJ25-05, ZMJ25-06, ZMJ25-07, ZMJ25-08, ZMJ25-09, ZMJ25-010, ZMJ25-011. Physical property tests were carried out on the products of the examples and comparative examples, specifically including specific surface area (m² / kg), grinding energy consumption (kWh / t), C3S reaction rate (%), 28-day strength (MPa). The specific test results are shown in Tables 2 and 3.

[0073] Table 2 shows the test results of specific surface area and grinding energy consumption

[0074] Table 3 shows the test results of C3S reaction rate and 28-day strength

[0075] The variable charge regulation mechanism improves the selective dispersion effect: In the examples, by precisely controlling the preparation of variable charge type modified bentonite nanosheets and adjusting the Li⁺ / Mg²⁺ molar ratio, the interlayer charge density was controlled at 0.5-1.2 eq / kg. This enables the grinding aid to achieve selective dispersion according to the surface charge characteristics of mineral powder particles. Comparing with the commercially purchased grinding aid and comparative examples, the specific surface area of the mineral powder in the examples is significantly higher, up to 500 m² / kg at most, while the commercially available grinding aid is only 410 m² / 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 dispersion ability of the grinding aid.

[0076] The ore phase structure directional induction mechanism stimulates the activity of mineral powder: The modified amino silane and the phosphorus-containing organic polymer chelate of the present invention act synergistically to achieve the directional induction of the ore phase structure. The Schiff base chelated silane formed by the modified amino silane and the specifically synthesized block polyphosphonate can act with the active components in the mineral powder to directionally induce changes in the ore phase structure. Judging from the test data, the C3S reaction rate in the examples reaches up to 88% at most, and the 28-day strength is up to 60 MPa at most, far exceeding 73% and 51.5 MPa of the commercially available grinding aid and the performance indicators of each comparative example, fully proving that this mechanism effectively stimulates the activity of the mineral powder and improves the degree of hydration reaction and strength of the mineral powder.

[0077] Synergistic effect in reducing grinding energy consumption: The synergistic effect of the variable charge regulation mechanism and the ore phase structure orientation induction mechanism not only improves the dispersion and activation performance but also significantly reduces the grinding energy consumption. The lowest grinding energy consumption in the examples is 25 kWh / t, lower than 30.5 kWh / t of the grinding aids on the market. This is because good dispersion reduces particle agglomeration, facilitating grinding, and the optimization of the ore phase structure makes the ore powder easier to grind fine, thus reducing the overall grinding energy consumption.

[0078] 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 made based on the present invention to solve substantially the same technical problems and achieve substantially the same technical effects are all covered by the protection scope of the present invention.

Claims

1. A grinding aid for ore powder, characterized in that, It consists 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; 5 - 10 parts of modified aminosilane.

2. The grinding aid for ore powder according to claim 1, characterized in that, The variable charge type modified bentonite nanosheets are obtained through the following steps: (a) Mix sodium - based bentonite with MgCl₂·6H₂O and LiCl according to 100 - 120% of the cation exchange capacity, and ultrasonically disperse in a solution with an ethanol / water volume ratio of 3:1 for 30 min; (b) Step - wise temperature - rising calcination: Keep at 200 °C for 1 h to fix magnesium ions between layers, and keep at 500 °C for 2 h to activate the migration of lithium ions; (c) The interlayer charge density is regulated to 0.5 - 1.2 eq / kg by the Li⁺ / Mg²⁺ molar ratio of 0.25 - 1.

0.

3. A grinding aid for ore powder according to claim 2, characterized in that: Step (b) is carried out in a rotary tube furnace with a rotation speed of 20 rpm and a heating rate of 5 °C / min.

4. The grinding aid for ore powder according to claim 1, wherein The modified aminosilane is a Schiff - base chelated silane, and its preparation steps are as follows: Mix γ - aminopropyltriethoxysilane and 2 - hydroxy - 1 - naphthaldehyde according to a molar ratio of 1:1.5, and react under nitrogen protection at 50 °C for 3 h. The reaction formula is as follows: 。 5. A mineral powder grinding aid according to claim 1, characterized in that, The phosphorus - containing organic polymer chelate is a block - type polyphosphonate, and its synthesis steps specifically include: Using 4 - cyano - 4 - (thiobenzoyl) pentanoic acid as a chain transfer agent, carry out RAFT polymerization of 2 - hydroxyethyl methacrylate and vinylphosphonic acid according to a molar ratio of 4:1, and react at 60 °C for 6 h to obtain a polymer with a molecular weight of 15000 ± 500 and a PDI ≤ 1.

2.

6. A preparation method of the ore powder grinding aid according to any one of claims 1-5, characterized in that, It includes the following steps: Step 1: Premix the variable charge type modified bentonite nanosheets and the phosphorus - containing polymer chelate in an inert atmosphere at 38 - 42 °C for 30 min; Step 2: Dropwise add a 20 wt% ethanol solution of modified aminosilane 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 the grinding aid powder.

7. The preparation method of the ore powder grinding aid according to claim 6, characterized in that: In Step 2, the Zeta potential of the system is monitored in real - time. When the potential change ≥ 5 mV, stop dropping the ethanol solution of modified aminosilane, stir for 10 min until the potential is stable, and then continue.

8. The preparation method of the ore powder grinding aid according to claim 6, characterized in that: In Step 3, the atomization particle size of supercritical spray drying is controlled at 10 - 20 μm, and the CO₂ flow rate is 50 L / min.

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