Modified mineral powder and preparation method thereof

Abstract

The invention relates to the technical field of modified mineral powder and preparation thereof, in particular to modified mineral powder and a preparation method thereof.The preparation method comprises the following steps that iron-making blast furnace slag serves as a raw material and is fed into a ball mill to be subjected to staged grinding, and then metal impurities are removed; the mineral powder after impurity removal is placed in hot air circulation drying equipment to be dried, the mineral powder is cooled to the room temperature and then screened, and target mineral powder is obtained; the D97 particle size of the target mineral powder is tested through a laser particle analyzer, and the total dosage and the compounding proportion of the modifier are adjusted according to the D97 particle size; the material temperature is monitored in real time; the mixed materials are naturally cooled to the temperature below the preset temperature and fed into a jet mill to be subjected to graded grinding, grinding process parameters are adjusted according to the material agglomeration degree, and the materials obtained after secondary grinding are placed in vacuum drying equipment to be subjected to deep drying; sealing and packaging the modified mineral powder; and unqualified materials are returned to corresponding procedures according to defect types for reworking treatment. The preparation stability of the modified mineral powder is improved.

Description

Technical Field

[0001] This invention relates to the field of modified mineral powder and its preparation technology, and in particular to a modified mineral powder and its preparation method. Background Technology

[0002] Blast furnace slag is a major solid waste generated during the ironmaking process. After grinding, it forms mineral powder, which is traditionally widely used in the building materials industry. However, in recent years, the sluggish market in the building materials industry has hindered the utilization of blast furnace slag mineral powder. The accumulation of large amounts of solid waste not only occupies land resources but also poses environmental pollution risks, making it urgent to explore new directions for the resource utilization of solid waste.

[0003] On the other hand, the plastics industry commonly uses natural minerals such as calcium carbonate as fillers to prepare filler masterbatches in order to reduce production costs and improve product performance. However, the large-scale mining of natural minerals damages the ecological environment and does not meet the requirements of resource conservation and sustainable development. Blast furnace slag powder, as an industrial solid waste, has a chemical composition and physical properties similar to natural minerals, and has the potential to replace calcium carbonate in the plastics industry. However, unmodified blast furnace slag powder has strong hydrophilicity and high surface energy, resulting in poor compatibility with hydrophobic plastic substrates. Direct addition will lead to uneven dispersion and severe agglomeration of filler masterbatches, thereby affecting the mechanical and processing properties of plastic products. At the same time, the high oil absorption value of the raw slag powder will consume plasticizers and other components in the plastic substrate, further reducing product quality. In addition, the small amount of residual metal impurities, incompletely ground coarse particles, and problems such as uneven dispersion and incomplete reaction of additives during the modification process may all restrict its application effect in the plastics industry. Summary of the Invention

[0004] Therefore, the present invention provides a modified mineral powder and its preparation method to overcome the problem in the prior art that the production stability of modified mineral powder is reduced due to the inaccurate determination of the stirring uniformity and material temperature fluctuation values ​​reflected by the stirring parameters.

[0005] To achieve the above objectives, the present invention provides a modified mineral powder and a method for preparing the same, comprising the following steps: Step S1: The blast furnace slag is fed into a grinding mill for staged grinding to remove metal impurities. Then, the ore powder is separated by an air classifier. The separated ore powder is placed in a hot air circulating drying equipment for drying. After cooling to room temperature, it is screened to obtain the target ore powder. Step S2: Use a laser particle size analyzer to test the D97 particle size of the target mineral powder, and adjust the total amount of modifier and the compounding ratio according to the D97 particle size. Step S3: Add the target mineral powder into a high-speed mixer, determine the initial stirring speed according to the particle size of the mineral powder, and then add the compounded modifier in batches. Adjust the addition interval dynamically according to the temperature fluctuation of the material in the mixer, keep it warm and stir for a period of time, and monitor the material temperature in real time. Step S4: The mixed material is naturally cooled to below the preset temperature and sent to an air jet mill for graded grinding. The grinding process parameters are adjusted according to the degree of material agglomeration. The material after secondary grinding is placed in a vacuum drying equipment for deep drying. Step S5: Test the dried material. If the material passes the test, remove a small amount of agglomerated particles by passing a standard sieve and seal the modified mineral powder. If the material fails the test, return it to the corresponding process for rework according to the defect type.

[0006] Furthermore, the method for adjusting the total amount of modifier and the compounding ratio based on the D97 particle size is as follows: When the particle size of D97 is smaller than the preset particle size, the amount of modifier is adjusted to the preset first modifier addition amount; When the particle size of D97 is greater than or equal to the preset particle size, the amount of modifier is adjusted to the preset amount of the second modifier.

[0007] Furthermore, the specific steps of step S3 include: The target mineral powder is added to a high-speed mixer with a special-structure stirring paddle equipped with temperature sensing and variable frequency speed regulation, and stirring is started. The initial stirring speed is determined based on the D97 particle size. The temperature is gradually increased to the preset preheating temperature, and the material movement is obtained to determine the range of stirring speed variation. The compounded modifier was then added in multiple batches, and the addition interval was dynamically adjusted according to the temperature fluctuation of the material in the mixer. The temperature was then raised to the preset reaction temperature, the stirring speed was adjusted to the appropriate range, and the mixture was kept warm and stirred, while the material temperature was monitored in real time.

[0008] Furthermore, the method for determining the initial stirring speed based on the D97 particle size is as follows: When the particle size of D97 is smaller than the preset particle size, the initial stirring speed is adjusted to the preset first initial speed; When the particle size of D97 is greater than or equal to the preset particle size, the initial stirring speed is adjusted to the preset second initial speed.

[0009] Furthermore, the method for determining the variation range of the stirring speed is to calculate the stirring parameters by obtaining the material splash amplitude and the proportion of agglomerate volume. If the stirring parameter is less than or equal to the preset parameter threshold, the stirring uniformity is determined to be within the allowable range, and the stirring speed is increased according to the preset adjustment coefficient. If the stirring parameter is greater than the preset parameter threshold, it is determined that the stirring uniformity is below the allowable range, and the preset adjustment coefficient is re-determined.

[0010] Furthermore, the method for redetermining the preset adjustment coefficient is to redetermine the preset adjustment coefficient based on the ratio of the stirring parameter to the preset parameter threshold.

[0011] Furthermore, the method for dynamically adjusting the addition interval based on the temperature fluctuation of the material inside the mixer involves obtaining the temperature fluctuation value of the material inside the mixer after adding the modifier. If the temperature fluctuation value is within the preset stable range, then add the modifier according to the current interval. If a single temperature fluctuation exceeds the preset stable range, the current interval duration will be redefined.

[0012] Furthermore, the interval duration is redetermined based on the absolute value of the temperature fluctuation variance.

[0013] Furthermore, the method for adjusting the grinding process parameters according to the degree of material agglomeration is to determine the grinding pressure based on the agglomeration ratio.

[0014] Furthermore, the formulation of modified mineral powder includes: 90-98 parts mineral powder, 1-3 parts silane coupling agent, 1-3 parts aluminate coupling agent, 1-3 parts titanate coupling agent, and 1-3 parts stearic acid.

[0015] Furthermore, the mineral powder has a particle size of 600-1250 mesh, and the modified mineral powder formula includes: 95-98 parts mineral powder, 0-2 parts aluminate coupling agent, and 0-5 parts stearic acid.

[0016] Furthermore, the particle size of the mineral powder is 1250-2500 mesh, and the formula of the modified mineral powder includes: 93-96 parts of mineral powder, 1-3 parts of silane coupling agent, 1-3 parts of aluminate coupling agent, and 1-3 parts of titanate coupling agent.

[0017] Furthermore, the particle size of the mineral powder is 2500-5000 mesh, and the formula of the modified mineral powder includes: 90-96 parts of mineral powder, 0-2 parts of silane coupling agent, 1-2 parts of aluminate coupling agent, 1-3 parts of titanate coupling agent, and 1-3 parts of stearic acid.

[0018] Compared with the prior art, the beneficial effects of the present invention are that the raw material pretreatment adds impurity removal, particle size distribution control and chemical composition limitation, effectively removes metal impurities and coarse particles, ensures the purity and uniformity of mineral powder, avoids the adverse effects of impurities on plastic processing equipment and product performance, and ensures that the modification reaction is carried out effectively.

[0019] The modifier adopts a precise compounding system, which utilizes the synergistic effect of different coupling agents and the hydrophobic modification effect of stearic acid to significantly enhance the synergistic effect of mineral powder surface modification; at the same time, the purity and physicochemical indicators of the additives are limited to avoid modification failure caused by inferior additives.

[0020] The gradient temperature-controlled high-speed mixing process incorporates technical features such as the type of stirring paddle, segmented control of heating rate, and limitation of temperature fluctuation range. Combined with the batch addition of additives, it ensures that the modified additives are uniformly dispersed in a semi-molten state and fully bond and coat the surface of the mineral powder, solving the problems of additive agglomeration and insufficient reaction in traditional processes. The post-processing adds graded grinding and vacuum secondary drying to further optimize the particle size distribution and moisture content control of the mineral powder and improve the stability of mineral powder modification. Attached Figure Description

[0021] Figure 1 This is an overall flow chart of the preparation method of modified mineral powder according to an embodiment of the present invention; Figure 2 This is a detailed flowchart of step S3 in the preparation method of modified mineral powder according to an embodiment of the present invention; Figure 3 This is a flowchart illustrating the determination of the initial stirring speed in the preparation method of modified mineral powder according to an embodiment of the present invention. Figure 4 This is a flowchart illustrating the process of re-determining the current interval duration in the preparation method of modified mineral powder according to an embodiment of the present invention. Detailed Implementation

[0022] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0023] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0024] Please see Figure 1 , Figure 2 , Figure 3 as well as Figure 4 The diagrams shown are, respectively, an overall flowchart of the preparation method of modified mineral powder according to an embodiment of the present invention, a detailed flowchart of step S3, a detailed flowchart of determining the initial stirring speed, and a detailed flowchart of re-determining the current interval duration. The present invention provides a method for preparing modified mineral powder, characterized by comprising the following steps: Step S1: The blast furnace slag is fed into a grinding mill for staged grinding to remove metal impurities. Then, the ore powder is separated by an air classifier. The separated ore powder is placed in a hot air circulating drying equipment for drying. After cooling to room temperature, it is screened to obtain the target ore powder. Step S2: Use a laser particle size analyzer to test the D97 particle size of the target mineral powder, and adjust the total amount of modifier and the compounding ratio according to the D97 particle size. Step S3: Add the target mineral powder to a high-speed mixer with a temperature sensor and variable frequency speed control function. Determine the initial stirring speed according to the D97 particle size. Then add the compounded modifier in batches. Adjust the addition interval dynamically according to the temperature fluctuation of the material in the mixer. Keep the mixture warm and stir for a period of time, and monitor the material temperature in real time. Step S4: The mixed material is naturally cooled to below the preset temperature and sent to an air jet mill for graded grinding. The grinding process parameters are adjusted according to the degree of material agglomeration. The material after secondary grinding is placed in a vacuum drying equipment for deep drying. Step S5: Test the dried material. If the material passes the test, remove a small amount of agglomerated particles by passing a standard sieve and seal the modified mineral powder. If the material fails the test, return it to the corresponding process for rework according to the defect type.

[0025] In the specific implementation process, the D97 particle size refers to the particle size value corresponding to when the cumulative particle size distribution of a powder sample reaches 97% from small to large.

[0026] Among them, the high-speed mixer is equipped with a detection device for the amplitude of material splash and the proportion of agglomeration volume. The detection device can be a vision detection system or a non-vision detection system, both of which can realize real-time or intermittent detection of parameters, providing accurate data for the calculation of mixing parameters.

[0027] For example, a vision detector equipped with a dust-proof, high-temperature-resistant coated lens and a miniature blowing device can be used to remove mineral powder dust from the lens surface in real time, preventing dust from obscuring the image. Alternatively, a high-speed frame rate industrial camera can be selected, paired with a high-brightness infrared supplementary lighting module, to solve the image blurring problem under high-speed stirring and clearly capture the instantaneous state of material splashing and the external morphology of agglomerates. Furthermore, an automatic online sampling device can be installed at the mixer's discharge port to perform intermittent sampling at certain intervals. After sampling, the samples are quickly sieved using a miniature vibrating screen (with a screen set to the preset upper limit of single particle size), yielding sieving results within 30 seconds. The results are calculated using the formula "agglomerate volume ratio = agglomerate volume on the screen / total sampled material volume," and the detection results are directly fed back to the control system. It is understood that as long as the material splash amplitude and agglomerate volume ratio can be obtained, all optimization and substitution methods are conventional technical means in the relevant technical field and will not be elaborated upon here.

[0028] In the specific implementation process, the material dried in step S4 is subjected to comprehensive testing. The testing items include: ① Particle size characteristics (particle size distribution and D97 particle size measured by laser particle size analyzer), which must meet the requirements of 800-5000 mesh; ② Physicochemical properties (moisture content ≤0.2% by drying method, oil absorption value ≤20g / 100g by oil absorption value test method); ③ Surface properties (water contact angle ≥150° by static drop method, surface free energy ≤35mJ / m² by surface free energy tester); After passing the test, the material is sealed and packaged; the material that fails the test is returned to step S4 for re-grading and grinding or returned to step S3 for secondary modification with modifier until the quality standard is met.

[0029] Specifically, the grinding mill is a machine capable of grinding blast furnace slag into powder, such as a ball mill, which will not be described in detail here.

[0030] Specifically, the target mineral powder particle size is 800-5000 mesh.

[0031] Specifically, the method for adjusting the total amount of modifier and the compounding ratio based on the D97 particle size is as follows: When the particle size of D97 is smaller than the preset particle size, the amount of modifier is adjusted to the preset first modifier addition amount; When the particle size of D97 is greater than or equal to the preset particle size, the amount of modifier is adjusted to the preset amount of the second modifier.

[0032] In the specific implementation process, the preset particle size, the preset amount of the first modifier, and the preset amount of the second modifier are obtained through multiple experiments. Here, a preset particle size of 2500 mesh is provided, the preset amount of the first modifier is 1.5%-2.0% of the mineral powder mass, and the preset amount of the second modifier is 1.0%-1.5% of the mineral powder mass.

[0033] The specific compounding combinations are divided into the following two types: ① Binary compounding system: suitable for coarse-grained mineral powder (600-1250 mesh). Since coarser-grained mineral powder has a smaller specific surface area and is relatively less prone to agglomeration, a simple compounding system is selected, which is composed of aluminate coupling agent and stearic acid in a mass ratio of 1:1-3. The aluminate coupling agent is one of DL-411 or DL-411A; ② Ternary compounding system: suitable for fine-grained mineral powder (1250-2500 mesh). The mineral powder has a larger specific surface area and is prone to agglomeration, requiring higher interfacial bonding ability of the modifier. Therefore, the modifier is composed of aluminate coupling agent, silane coupling agent and titanate coupling agent in a mass ratio of 1-2:1-2:1. The silane coupling agent is one or two of KH-550 and KH-570, and the titanate coupling agent is one of TC-105 and TC-201. ③ Quaternary compound system: suitable for ultrafine particle size mineral powder (2500-5000 mesh). The mineral powder is very easy to agglomerate. Therefore, the modifier is composed of silane coupling agent, aluminate coupling agent, titanate coupling agent and stearic acid in a mass ratio of 0-1:1-2:1-3:1-3.

[0034] Specifically, step S3 includes the following steps: Step S31: Add the target mineral powder into a high-speed mixer with a special structure stirring paddle and temperature sensing and variable frequency speed regulation function, and start stirring; Step S32: Determine the initial stirring speed based on the D97 particle size, gradually increase the temperature to the preset preheating temperature, and obtain the material movement status to determine the range of stirring speed change; Step S33: The compounded modifier is then added in multiple batches, and the addition interval is dynamically adjusted according to the temperature fluctuation of the material in the mixer. The temperature is then raised to the preset reaction temperature, the stirring speed is adjusted to the appropriate range, and the mixture is kept warm and stirred. The material temperature is monitored in real time.

[0035] In the specific implementation process, the temperature is gradually increased to the preset preheating temperature (60-80℃) at a heating rate of 3-12℃ / min, and stirred for 5-20 minutes to ensure that the temperature uniformity error of the mineral powder is ≤2℃. Then, the compounded modifier is added in 2-3 portions, with the first addition being 40%-50% of the total amount, and the remaining amount being added in each subsequent addition in equal portions until all the modifier has been added. The temperature is then increased to the preset reaction temperature (90-130℃) at a heating rate of 2-5℃ / min. The initial stirring speed, determined according to the D97 particle size, is adjusted to 1500-2000 r / min, and stirred for 5-30 minutes. During this period, the material temperature is recorded every 5 minutes to maintain the temperature fluctuation within ±3℃, ensuring that the modifier fully chemically bonds and physically coats the surface of the mineral powder in a semi-molten state.

[0036] Specifically, the method for determining the initial stirring speed based on the D97 particle size is as follows: When the particle size of D97 is smaller than the preset particle size, the initial stirring speed is adjusted to the preset first initial speed; When the particle size of D97 is greater than or equal to the preset particle size, the initial stirring speed is adjusted to the preset second initial speed.

[0037] In the specific implementation process, the preset range of the first initial velocity is [800-1000] r / min; the preset range of the second initial velocity is [1000-1200] r / min.

[0038] For D97 mineral powder with larger particle size and coarser particle size distribution, due to its larger particle mass and relatively lower surface energy, the agglomeration phenomenon is not obvious. If the initial stirring speed is too high, the material will easily splash violently in the mixer, failing to fully contact the stirring paddle and the inner wall of the mixer, affecting the preheating uniformity. Therefore, the initial stirring speed is determined based on the principle of "being able to smoothly drive the mineral powder to flow as a whole without obvious splashing", ensuring that the mineral powder gradually absorbs heat under gentle stirring and achieves temperature uniformity. For D97 mineral powder with small particle size and fine particle size distribution, due to its large specific surface area and high surface energy, it is very easy for it to adsorb each other and form agglomerates. If the initial stirring speed is too low, it is difficult to break the agglomerate structure, resulting in uneven dispersion of mineral powder. The subsequent modifier cannot fully interact with the surface of individual mineral powder particles. Therefore, the initial stirring speed is determined based on the principle of "effectively breaking up agglomerated particles and making the mineral powder form a uniform fluidized state". With appropriate stirring intensity, the mineral powder particles are quickly mixed and fully exchanged with heat in the mixer, improving preheating efficiency and material uniformity.

[0039] Specifically, the method for determining the variation range of stirring speed is to calculate the stirring parameters by obtaining the material splash amplitude and the proportion of agglomerate volume. If the stirring parameter is less than or equal to the preset parameter threshold, the stirring uniformity is determined to be within the allowable range, and the stirring speed is increased according to the preset adjustment coefficient. If the stirring parameter is greater than the preset parameter threshold, it is determined that the stirring uniformity is below the allowable range, and the preset adjustment coefficient is re-determined.

[0040] In the specific implementation process, the calculation method for stirring parameters is as follows:

[0041] Where C is the stirring parameter, α1 is the preset material splash amplitude characterization coefficient, f is the material splash amplitude, α2 is the agglomeration volume ratio characterization coefficient, v is the agglomeration volume ratio, and α1+α2=1.

[0042] In the specific implementation process, the value range of f is 0-0.5, and the value range of v is 0-0.3. It can be understood that f and v are dimensionless numbers after normalization. The setting of the preset parameter threshold varies depending on the particle size of the mineral powder. Here, a preset parameter threshold range of 0.15-0.25 is provided.

[0043] Specifically, the method for redetermining the preset adjustment coefficient is to redetermine the preset adjustment coefficient based on the ratio of the stirring parameter to the preset parameter threshold.

[0044] In the specific implementation process, the preset adjustment coefficient is redefined as the product of the current preset adjustment coefficient and the ratio of the stirring parameter to the preset parameter threshold.

[0045] Specifically, the method for dynamically adjusting the addition interval based on the temperature fluctuation of the material inside the mixer involves obtaining the temperature fluctuation value of the material inside the mixer after adding the modifier. If the temperature fluctuation value is within the preset stable range, then add the modifier according to the current interval. If a single temperature fluctuation exceeds the preset stable range, the current interval duration will be redefined.

[0046] Specifically, the interval duration is redetermined based on the absolute value of the temperature fluctuation variance.

[0047] In the specific implementation process, it is understood that the calculation method of temperature fluctuation variance is a commonly used technical means in the field of art, and will not be elaborated here. The interval duration is determined by the sum of the current interval duration and the absolute value of temperature fluctuation variance.

[0048] If a single temperature fluctuation value is within the preset stable range, it indicates that the reaction between the modifier and the mineral powder is mild, the heat dissipation of the material and the heat release of the reaction are in balance, the modifier can be evenly dispersed in the material, and there is no local aggregation reaction. At this time, there is no need to extend the addition interval. Just maintain the currently set basic interval time to ensure that the modifier is added gradually according to the plan and to maintain the continuity and uniformity of the reaction.

[0049] If a single temperature fluctuation exceeds the preset stable range, it indicates that after the modifier is added, the reaction in a localized area is intensely exothermic, and the heat cannot be dissipated in time. If the next batch of modifier is added at the original interval, it will lead to further heat accumulation, which may cause uneven melting of the modifier, localized overheating and decomposition, or the formation of new agglomerates due to high temperature adhesion of mineral powder particles. Therefore, the addition interval should be extended immediately. The next batch of modifier should only be added after the temperature fluctuation has stabilized.

[0050] Specifically, the method for adjusting grinding process parameters according to the degree of material agglomeration is to determine the grinding pressure based on the agglomeration ratio.

[0051] Specifically, the calculation method for the reunification rate is as follows:

[0052] Where T represents the percentage of family reunions, t i Let t0 be the weight of the aggregated mineral powder sampled in the i-th sampling, t0 be the weight of a single sampling, and n be the number of samplings, i=1,2……n.

[0053] In the specific implementation process, When the agglomeration rate is ≤5%, the grinding pressure is 0.6-0.7MPa and the grinding time is 10-15min; When the agglomeration rate is greater than 5%, the grinding pressure is 0.7-0.8 MPa and the grinding time is 15-20 min.

[0054] In the specific implementation process, if the agglomerate ratio is >15%, it is considered severe agglomeration. It is first treated with a low-speed stirring pre-dispersion device for 10 minutes, and then a staged grinding process of "low-pressure coarse grinding + high-pressure fine grinding" is adopted. The first stage is grinding at 0.6-0.7MPa for 8-10 minutes, and the second stage is grinding at 0.7-0.8MPa for 10-12 minutes.

[0055] The material after secondary grinding is placed in a vacuum drying equipment and dried for 30-60 minutes at a temperature of 70-80℃ and a vacuum of -0.08MPa to further remove residual moisture from the material and ensure that the final mineral powder moisture content is ≤0.2%.

[0056] Specifically, the formulation of modified mineral powder includes: 90-98 parts mineral powder, 1-3 parts silane coupling agent, 1-3 parts aluminate coupling agent, 1-3 parts titanate coupling agent, and 1-3 parts stearic acid.

[0057] Specifically, the mineral powder has a particle size of 600-1250 mesh, and the modified mineral powder formula includes: 95-98 parts mineral powder, 0-2 parts aluminate coupling agent, and 0-5 parts stearic acid.

[0058] Specifically, the mineral powder has a particle size of 1250-2500 mesh, and the modified mineral powder formula includes: 93-96 parts mineral powder, 1-3 parts silane coupling agent, 1-3 parts aluminate coupling agent, and 1-3 parts titanate coupling agent.

[0059] Specifically, the mineral powder has a particle size of 2500-5000 mesh, and the modified mineral powder formula includes: 90-96 parts mineral powder, 0-2 parts silane coupling agent, 1-2 parts aluminate coupling agent, 1-3 parts titanate coupling agent, and 1-3 parts stearic acid. Example

[0060] The intermediate ore powder is obtained by coarse grinding of blast furnace slag in a ball mill and air classification. A combination of magnetic separation and air separation is used to remove metallic impurities and large-diameter non-metallic particles. After hot air circulation drying and high-precision standard sieve screening, the target ore powder with a D97 particle size of 4500 mesh is obtained.

[0061] The mineral powder was confirmed to be of ultrafine particle size by a laser particle size analyzer. A quaternary compound modifier consisting of silane coupling agent, aluminate coupling agent, titanate coupling agent, and stearic acid was selected, with each part accounting for 1.2% of the mineral powder mass.

[0062] The target mineral powder was added to a high-speed mixer. Based on the tendency of ultrafine particles to agglomerate, the initial stirring speed was determined to be 1100 rpm. After heating to the preset preheating temperature, the mixture was kept at this temperature and stirred to initially fluidize the mineral powder. The modifier was added in three portions. After the first addition of 40%, the material temperature suddenly rose beyond the stable range, so the addition interval was extended to 8 minutes. After the temperature stabilized, the remaining modifier was added in two more portions. The temperature was raised to the preset reaction temperature, and the stirring speed was adjusted to 1900 rpm. The mixture was kept at this temperature and stirred to ensure that the modifier fully bonds and coats the mineral powder particles.

[0063] The mixture was cooled to below 40°C and first fed into a low-speed stirring and pre-dispersing device for 10 minutes to initially break up hard agglomerates. Then, it was fed into an air jet mill for staged grinding: for agglomerates of 12% and >5%, the first stage used a grinding pressure of 0.7 MPa for 8 minutes, after which a sample was taken and tested, and the agglomerate content decreased to 8%. In the second stage, the grinding pressure was increased to 0.8 MPa, and grinding continued for 12 minutes. After grinding, the mixture was thoroughly dried in a vacuum drying machine to control the moisture content to ≤0.2%.

[0064] The oil absorption value was 14g / 100g, the contact angle was 150°, and the particle size distribution range met the preset standards. After sieving, it was sealed and packaged as qualified modified mineral powder.

[0065] Blast furnace slag is a major industrial solid waste generated by the ironmaking industry. Traditional stockpiling methods occupy a large amount of land resources and may lead to heavy metal ion leakage due to rainwater runoff, polluting the soil and groundwater. Grinding blast furnace slag into mineral powder and modifying it for use in plastic filler masterbatches can significantly increase the amount of solid waste disposed of, turning waste into treasure, reducing the environmental pollution risks from solid waste accumulation at the source, and lowering the solid waste disposal costs for enterprises. Traditional fillers in the plastics industry are mostly natural minerals such as calcium carbonate and talc. Their mining process damages mountain vegetation, causes soil erosion, and exacerbates ecological degradation. Modified blast furnace slag mineral powder has similar physicochemical properties to natural mineral fillers and can directly or partially replace natural minerals, reducing dependence on non-renewable mineral resources, protecting ecological landscapes, achieving the resource substitution goal of "replacing minerals with waste," and promoting sustainable resource utilization. The raw material for blast furnace slag mineral powder is industrial waste residue, and the energy consumption for grinding and modification is far lower than the energy consumption for mining and processing natural minerals. The high proportion of modified mineral powder used in plastics can reduce the consumption of fossil resources in plastic product production, indirectly reduce carbon emissions during fossil energy extraction and processing, and help the industrial chain achieve green and low-carbon transformation.

[0066] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A modified mineral powder, characterized in that, The formulation of modified mineral powder includes: 90-98 parts mineral powder, 1-3 parts silane coupling agent, 1-3 parts aluminate coupling agent, 1-3 parts titanate coupling agent, and 1-3 parts stearic acid.

2. The modified mineral powder according to claim 1, characterized in that, The mineral powder has a particle size of 600-1250 mesh, and the modified mineral powder formula includes: 95-98 parts mineral powder, 0-2 parts aluminate coupling agent, and 0-5 parts stearic acid.

3. The modified mineral powder according to claim 1, characterized in that, The mineral powder has a particle size of 1250-2500 mesh, and the modified mineral powder formula includes: 93-96 parts mineral powder, 1-3 parts silane coupling agent, 1-3 parts aluminate coupling agent, and 1-3 parts titanate coupling agent.

4. The modified mineral powder according to claim 1, characterized in that, The mineral powder has a particle size of 2500-5000 mesh, and the modified mineral powder formula includes: 90-96 parts mineral powder, 0-2 parts silane coupling agent, 1-2 parts aluminate coupling agent, 1-3 parts titanate coupling agent, and 1-3 parts stearic acid.

5. A method for preparing the modified mineral powder according to any one of claims 1-4, characterized in that, Includes the following steps: Step S1: The blast furnace slag is fed into a grinding mill for staged grinding to remove metal impurities. Then, the ore powder is separated by an air classifier. The separated ore powder is placed in a hot air circulating drying equipment for drying. After cooling to room temperature, it is screened to obtain the target ore powder. Step S2: Use a laser particle size analyzer to test the D97 particle size of the target mineral powder, and adjust the total amount of modifier and the compounding ratio according to the D97 particle size. Step S3: Add the target mineral powder into a high-speed mixer, determine the initial stirring speed according to the D97 particle size, then add the compounded modifier in batches, dynamically adjust the addition interval according to the temperature fluctuation of the material in the mixer, keep it warm and stir for a period of time, and monitor the material temperature in real time. Step S4: The mixed material is naturally cooled to below the preset temperature and sent to an air jet mill for graded grinding. The grinding process parameters are adjusted according to the degree of material agglomeration. The material after secondary grinding is placed in a vacuum drying equipment for deep drying. Step S5: Test the dried material. If the material passes the test, remove a small amount of agglomerated particles by passing a standard sieve and seal the modified mineral powder. If the material fails the test, return it to the corresponding process for rework according to the defect type.

6. The method for preparing modified mineral powder according to claim 5, characterized in that, The method for adjusting the total amount of modifier and the compounding ratio based on the particle size of D97 is as follows: When the particle size of D97 is smaller than the preset particle size, the amount of modifier is adjusted to the preset first modifier addition amount; When the particle size of D97 is greater than or equal to the preset particle size, the amount of modifier is adjusted to the preset amount of the second modifier.

7. The method for preparing modified mineral powder according to claim 5, characterized in that, The specific steps of step S3 include: The target mineral powder is added to a high-speed mixer with a special-structure stirring paddle equipped with temperature sensing and variable frequency speed regulation, and stirring is started. The initial stirring speed is determined based on the D97 particle size. The temperature is gradually increased to the preset preheating temperature, and the material movement is obtained to determine the range of stirring speed variation. The compounded modifier is added in multiple batches, and the addition interval is dynamically adjusted according to the temperature fluctuation of the material in the mixer. The temperature is then raised to the preset reaction temperature, the stirring speed is adjusted to the appropriate range, and the mixture is kept warm while stirring. The material temperature is monitored in real time.

8. The method for preparing modified mineral powder according to claim 7, characterized in that, The method for determining the initial stirring speed based on the D97 particle size is as follows: When the particle size of D97 is smaller than the preset particle size, the initial stirring speed is adjusted to the preset first initial speed; When the particle size of D97 is greater than or equal to the preset particle size, the initial stirring speed is adjusted to the preset second initial speed; The method for determining the variation range of stirring speed is to calculate the stirring parameters by obtaining the material splash amplitude and the proportion of agglomerate volume. If the stirring parameter is less than or equal to the preset parameter threshold, the stirring uniformity is determined to be within the allowable range, and the stirring speed is increased according to the preset adjustment coefficient. If the stirring parameter is greater than the preset parameter threshold, it is determined that the stirring uniformity is below the allowable range, and the preset adjustment coefficient is re-determined. The method for redetermining the preset adjustment coefficient is to redetermine the preset adjustment coefficient based on the ratio of the stirring parameter to the preset parameter threshold.

9. The method for preparing modified mineral powder according to claim 7, characterized in that, The method for dynamically adjusting the addition interval based on the temperature fluctuation of the material inside the mixer involves obtaining the temperature fluctuation value of the material inside the mixer after adding the modifier. If the temperature fluctuation value is within the preset stable range, then add the modifier according to the current interval. If a single temperature fluctuation exceeds the preset stable range, the current interval duration will be redefined. The interval duration is redetermined based on the absolute value of the temperature fluctuation variance.

10. The method for preparing modified mineral powder according to claim 5, characterized in that, The method for adjusting grinding process parameters according to the degree of material agglomeration is to determine the grinding pressure based on the agglomeration ratio.

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